Machinery health monitoring system for vertical turbine pump

'Machinery Health Monitoring System for Vertical Turbine Pump

by

THUYETLE

Submitted to the MECHANICAL ENGINEERING TECHNOLOGY DEPARTMENT

In Partial Fulfillment of the Requirements for the

Degree of

Bachelor of Science m

MECHANICAL ENGINEERING TECHNOLOGY

at the

OMI College of Applied Science University of Cincinnati

May 2008

© ...... ThuyetLe

The author hereby grants to the Mechanical Engineering Technology Department permission to reproduce and distribute copies of this thesis document in whole or in part.

Accepted by 1 Muthar Al- ba1d1, PhD, Department Head

Mechanical Engineering Technology

MACHINERY HEALTH MONITORING SYSTEM

FOR VERTICAL TURBINE PUMP

By

THUYET LE

Advised by

Dr. JANAK DAVE

Submitted to the Mechanical Engineering Technology Department

OMI College of Applied Science University of Cincinnati

May 2008

I

ABSTRACT In an effort to provide better reliability services to customers, Vibration Technology

US Group (VTU) has researched for a means to provide a reliable machinery health condition monitoring system. A survey was conducted at VTU’s client sites in September 2007 to identify the customers’ requirements. The following list presents those results:

• Timely alerts to critical fault signals (weighted 19%) • Continuous equipment monitoring (weighted 15%) • Failure prediction (weighted 15%) • Increased reliability of operations (weighted 15%). • Competitive cost (weighted 14%) • Reduction of data acquisition time (weighted 11%)

The machinery health monitoring system was implemented on a vertical turbine pump (VTP) which is widely used in oil producing and power generating industries to assist in transporting fluid from underground to a required elevation. To satisfy the customer requirements, the monitoring system was designed to provide the following characteristics:

• Competitive cost in comparison with unscheduled downtime costs • Centralize monitoring tasks in a center • Continuous equipment monitoring • Increase reliability of operations by properly detecting equipment faults • Reduction of vibration data acquisition time by 70% in comparison with

traditional methods • Timely alarm notification at critical fault signals • Baseline prediction capability

The project started on January, 7th 2008 with three concepts, which were Offline, Online-standalone, and Online-networking systems. The Online-networking system was selected because of its highest rate (based on the weighted decision matrix) in comparison with the other proposals. The design phase began on Jan, 28th and solidified on Feb, 6th 2008 with three addressed critical issues: measurement points, vibration severity criteria and data acquisition board. The location of the measurement points was based on ISO 5348:1998 (Mechanical vibration and shock), vibration severity standard was based on ISO 10816-3 (Vibration severity criteria), and data acquisition board was based on the 9901 model of Icon ®.

The field test was fulfilled from Apr 7th to Apr 13th to verify the capability of the design system to perform continuous data acquisition, fault trending, and fault alerting functions. The system proved its ability to the advisor on May 2nd and was brought to the Tech Expo on May 22nd. The project was orally presented to the faculty on Jun, 6th, and the final report was submitted on Jun, 9th.

The proposed budget of the project was $16,000, consisting of $15,500 for the monitoring system and $500 for travel expenses. However, the actual expenses totaled $500 because the major monitoring system components were donated by VTU ®.

II

TABLE OF CONTENTS

Table of Contents ABSTRACT ............................................................................................................................... I

TABLE OF CONTENTS .......................................................................................................... II

LIST OF ILLUSTRATIONS ................................................................................................... IV

INTRODUCTION .................................................................................................................... 5

BACKGROUND .................................................................................................................................................... 5PROBLEM ............................................................................................................................................................ 5

RESEARCH .............................................................................................................................. 6

MAINTENANCE METHODS .................................................................................................................................. 6MONITORING METHODS ..................................................................................................................................... 7VERTICAL TURBINE PUMP SYSTEM .................................................................................................................... 8

PRODUCT OBJECTIVES ....................................................................................................... 9

IDENTIFICATION OF VOICE OF CUSTOMER .......................................................................................................... 9IDENTIFICATION OF ENGINEERING CHARACTERISTICS ....................................................................................... 9MEASURABLE OBJECTIVES ............................................................................................................................... 10

SYSTEM DESIGN ................................................................................................................. 11

DESIGN ALTERNATIVES AND SELECTION .......................................................................................................... 11Offline system .............................................................................................................................. 11

Online-standalone system ............................................................................................................. 12

Online-networking system ............................................................................................................ 13

Selection ....................................................................................................................................... 14

VTP SYSTEM ANALYSIS ................................................................................................................................... 15Overview of the typical failure modes of the VTP ....................................................................... 15

Typical faults of an induction motor ............................................................................................ 16

Typical faults of a vertical turbine pump ...................................................................................... 18

MONITORING SYSTEM ANALYSIS ..................................................................................................................... 21Measurement points ...................................................................................................................... 21

Vibration severity standard ........................................................................................................... 22

Data acquisition system ................................................................................................................ 23

Component selection .................................................................................................................... 24

ASSEMBLY AND IMPLEMENTATION ............................................................................. 26

TESTING AND PROOF OF DESIGN .................................................................................. 28

TESTING AND RESULTS ..................................................................................................................................... 28PROOF OF DESIGN ............................................................................................................................................. 29

PROJECT MANAGEMENT .................................................................................................. 32

SCHEDULE ........................................................................................................................................................ 32BUDGET ............................................................................................................................................................ 33

III

CONCLUSION ....................................................................................................................... 34

REFERENCES ....................................................................................................................... 35

APPENDICES ........................................................................................................................ 36

APPENDIX A RESEARCH DOCUMENTS ........................................................................................................... 36APPENDIX B CUSTOMER SURVEY WITH RESULTS ......................................................................................... 43APPENDIX C PARETO ANALYSIS OF THE CUSTOMER SURVEY ...................................................................... 44APPENDIX D QUALITY FUNCTIONAL DEPLOYMENT MATRIX ........................................................................ 45APPENDIX E PROPOSED SCHEDULE ............................................................................................................... 46APPENDIX F BUDGET .................................................................................................................................... 47APPENDIX G SUPPORT LETTER ...................................................................................................................... 48APPENDIX H PROOF OF DESIGN STATEMENT ................................................................................................ 49APPENDIX I PRODUCT OBJECTIVES ............................................................................................................... 50APPENDIX J CONCEPT WEIGHT DECISION MATRIX ....................................................................................... 51APPENDIX K DATA ACQUISITION NODE SELECTION MATRIX ....................................................................... 52APPENDIX L BILL OF MATERIAL (BOM) ....................................................................................................... 53APPENDIX M MOTOR PARAMETERS .............................................................................................................. 54APPENDIX N PUMP PARAMETERS .................................................................................................................. 55APPENDIX O SAMPLE OF THE WORK ORDER RECORDS ................................................................................. 56APPENDIX P TERMINOLOGY .......................................................................................................................... 57

IV

LIST OF ILLUSTRATIONS Figure 1 - Manual Vibration Data Collecting Method ............................................................................ 5Figure 2 - Example of Vibration Pattern ................................................................................................. 6Figure 3 - An Example of the Offline Method ........................................................................................ 7Figure 4 - An Example of the Online Method ......................................................................................... 7Figure 5 - Typical Vertical Turbine Pump Installation ............................................................................. 8Figure 6 - Typical VTP Components ....................................................................................................... 8Figure 7 - Offline System ...................................................................................................................... 11Figure 8 - Online-standalone System ................................................................................................... 12Figure 9 - Online-networking System ................................................................................................... 13Figure 10 - Cause-Effect Diagram of the Typical VTP Failure Modes ................................................... 15Figure 11 - Typical Induction Motor Model .......................................................................................... 16Figure 12 - An Example of Rotor Bar Defect Signals ............................................................................. 17Figure 13 - Typical Vertical Turbine Pump (Courtesy of Sulzer Pump) ................................................. 18Figure 14 - An Example of the Impeller Defect Signals ........................................................................ 20Figure 15 - Recommended Vibration Measurement Points ................................................................. 21Figure 16 - Vibration Severity Criteria .................................................................................................. 22Figure 17 - Data Acquisition System Diagram ...................................................................................... 23Figure 18 - Monitoring System Layout ................................................................................................. 25Figure 19 - Designed Monitoring System Layout ................................................................................. 26Figure 20 - Monitoring System in the Field .......................................................................................... 27Figure 21 - Impeller Defect Spectrum .................................................................................................. 30Figure 22 - Sample Plots of Fault Trending Capability .......................................................................... 31

Table 1 - Data Acquisition Boards on Market ........................................................................................ 7Table 2 - Relative Weights of System Features ..................................................................................... 9Table 3 - Relative Importance Level of Engineering Characteristic .................................................... 10Table 4 - Typical Dominant Fault Frequencies of an Induction Motor ................................................ 17Table 5 - Typical Failure Modes of a Vertical Turbine Pump ............................................................. 19Table 6 - Found Faults of the Tested VTP ........................................................................................... 28Table 7 - Cost Comparison ................................................................................................................... 29

Machinery Health Monitoring System for Vertical Turbine Pump Thuyet Le

5

INTRODUCTION

Background Any mechanical device has characteristic vibration

patterns which help to identify its health condition. The patterns are dependent on the conditions of the operations and processes. By recognizing the changes of the vibration patterns, the failures that happen inside the equipment can be detected.

The common method to collect vibration data uses portable data acquisition devices with single or dual channels, such as the CSI 2120 as shown in Figure 1. It requires the vibration technician to walk for hours in the field to gather all needed data. Furthermore, to correctly gather the relevant data, the locations of vibration acquiring points (the positions where vibration transducers could be mounted on) must be properly spotted. This proper placement requires vibration data collectors to be well-trained and experienced; meanwhile, there are only a few mechanical engineers that possess those skills.

Additionally, in order to obtain operation reliability, the equipment must be monitored continuously. The manual method does not allow this task. Subsequently, demand for an online monitoring system has been rising. With the advent of Ethernet-based data acquisition devices (such as Daqbook or DI730… details in Research and Appendix A), a machinery condition online monitoring system can be achieved.

Problem Vibration Technology US Group (VTU) is a machinery consultant service group of

companies headquartered in Middletown, Ohio. VTU provides reliability services in many industrial fields, such as petroleum producing, chemical processing, and paper mills, around the world. During years spent investigating the problems of their customers’ equipment, VTU has realized that many of their customers have not had machinery health monitoring systems, or even if they have, the systems have not adequately reflected the equipments’ faults. Moreover, the various locations of the customers’ facilities require VTU’s staff to travel regularly and extensively. Realizing those issues, VTU is searching for a reliable online machinery health monitoring system to assist it and its customers in maintenance tasks.

The purpose of this project was to design a Machinery Health Condition Monitoring System (MHCMS) and implement it on a vertical turbine pump (VTP) system, so as to detect and predict its most frequent failures.

Figure 1 - Manual Vibration Data Collecting Method


6

RESEARCH

Maintenance Methods

Maintenance methods can be generally divided into four main categories:

• Reactive: equipment is operated until failures occur before taking any corrective actions.

• Preventive: equipment is inspected routinely and is rebuilt or replaced based on its time in service.

• Predictive: measure condition of equipment routinely and systematically. Corrective actions are planned only when necessary.

• Proactive: eliminate failures by systematically selecting reliable equipment, ensuring correct installation, removing the root cause of problems and taking timely corrective action based on the condition of the equipment.

Selecting an appropriate maintenance method depends on many factors, such as production rates, required precision level of products, required equipment reliability, and the availability of maintenance techniques. The mainly used techniques in industry are ultrasound analysis, thermograph analysis, and vibration analysis. Among them, vibration analysis (VA) has been known as the most powerful tool because it relates directly to equipment condition.

Any type of machinery (rotating, reciprocating or structure) has its own characteristic vibration pattern. This pattern reflects the machinery health condition of the equipment. Any damage or failure causes the pattern to change. The amount of change depends strongly upon the degrees of damage or the severity of failures. By monitoring the vibration patterns continuously and systematically, a whole picture of the equipment’s health condition is understood. Figure 2 shows an example of a vibration pattern measured at a turbine outboard bearing. Those signals express that the turbine was misaligned and that some looseness occurred at the outboard bearing housing.

Predictive or condition-based and proactive maintenance methods mainly rely on analyzed information from vibration data to determine the maintenance schedule, to control the maintenance budget, or to analyze the root cause of equipment failures; hence, vibration analysis is one of the key tools to a successful maintenance program.

Figure 2 - Example of Vibration Pattern


7

Monitoring Methods

Current monitoring methods are classified as offline or online according to the way data acquisition devices collect and organize data. They are grouped as offline if data is acquired manually and routinely, and is stored in network-independent analyzing devices. Figure 3 is an example of this type. An advantage of this method is in its portability. Vibration analysts use it to collect and analyze vibration signals of every single piece of equipment right at the field. However, for a maintenance program, it has revealed its inefficiency, especially as monitoring tasks must be performed on large numbers of equipment.

The monitoring systems are classified as online when their data acquisition devices support networking. Vibration data is collected continuously and stored in a central database which is systematically organized for later analyzing tasks. Figure 4 is an example of this type. The major advantages of this type are manageability, time saving, and trendability. The disadvantage of this system is, of course, high cost. Table 1 shows three data acquisition boards on the market. The DI730 has an advantage in price; however, 9901 shows its advantage by combining with the other features such as real-time, fault trending and fault alerting. (Refer to Appendix J for the Weight Decision Matrix chart)

Table 1 - Data Acquisition Boards on Market

Features DI730/Dataq 9901/Icon Daqbook/IOTech Real-time No Yes No Fault trending Yes Yes Yes Fault alerting Yes Yes Yes Trigger channels Yes Yes No Number of channels 16 16 16 Cost $3400 $4000 $5000

Figure 3 - An Example of the Offline

Figure 4 - An Example of the Online


8

Vertical Turbine Pump System

The designed machinery health monitoring system was deployed on the vertical turbine pump (VTP) system. VTPs have been widely using in the oil producing industry and power plants to assist in bringing fluid from the ground to the surface. Figure 5 shows a typical installation of a VTP system.

The foundation and frame structures are constructed to support the entire system load. The dynamic behavior of vertical rotating equipment requires that the support structure must be sufficiently rigid; if not, vibration of inside components will be amplified leading to VTP system failures. This issue needs to be considered carefully in the design phase prior to taking any further monitoring steps.

Appendix A shows some typical vertical

turbine pumps in the market. Most of them have similar main components as shown in Figure 6. The major components are a vertical AC motor, a mechanical seal, bearings, line shaft, and bowls with an impeller inside. The motor shaft is coupled with the line shaft. The total head of pumping application will determine the number of bowls attached to the line shaft.

Mr. Davis (interviewing note in Appendix A), principal consultant of VTU, revealed that mode shapes of the line shaft need to be studied to make sure that the system is not operated synchronously at its natural frequency.

It was also disclosed that motor and mechanical seal failures happen frequently. These problems were taken into consideration in the testing phase so as to figure out their root cause.

Figure 5 - Typical Vertical Turbine Pump Installation

Figure 6 - Typical VTP Components


9

PRODUCT OBJECTIVES

Identification of Voice of Customer The customer survey was conducted in fall quarter 2008 with VTU’s customers to identify the customer needs, requirements, and expectations. 30 samples were taken by three major methods: personal interviews, telephone, and e-questionnaires. The results (shown in Appendix B) show the level of importance that VTU and its customers would like to have in the designed monitoring system. Their expectations of the designed monitoring system were summarized as a list below (ratings are on a scale of 1 to 5):

• Timely alerting critical fault signals (rated 4.33), • Predicting the failures (rated 4.20), • Increasing reliability of operation (rated 4.20). • Competitive cost (rated 4.13), • Continuously monitoring the equipment (rated 3.93), • Reducing data collecting time (rated 3.5).

Note that, only the features, which had average ratings of about or greater than 3.5, were taken into account (this is the result of the Pareto’s analysis in Appendix C)

Only 10 out of 30 questionnaires had answers for satisfaction level. Based on those responses, the customers’ satisfaction levels with their current systems (or the systems they knew) were rated below (on a scale of 1 to 5):

• Timely alerting critical failures (rated 2.30). • Reducing data collecting time (rated 2.6), • Continuously monitoring equipment (rated 2.60), • Predicting the failures (rated 2.80), • Competitive cost (rated 2.80), • Increasing reliability of operation (rated 2.90).

Identification of Engineering Characteristics Table 2 shows the relative weights of the measureable customer features. Alerting feature was weighted the highest value, 19%; data collecting time feature had the lowest weight, 11% (refer to Appendix C for the Quality Functional Deployment matrix)

Table 2 - Relative Weights of System Features Feature Weight Timely alerting critical events 19% Continuously online monitoring 15% Baseline prediction 15% Increasing reliability of operation 15% Competitive cost 14% Centralize monitoring tasks 12% Reducing data collecting time 11%


10

The features from Table 2 were also analyzed with respect to the engineering characteristics to determine which engineering characteristics should be concentrated on to achieve the customer requirements. Table 3 summarizes the relative importance of the monitoring system characteristics. Real-time data acquisition is the most important one because it affects on the system capability to timely and correctly detect the fault signals.

Table 3 - Relative Importance Level of Engineering Characteristic

Engineering Characteristic Relative Importance Real-time data acquisition 19%

Fault trending 18% Fault alerting 18% Networking 15%

Event triggering 14% Dynamic range 9%

Number of channels 9%

Measurable Objectives

The following is the list of the objectives that were proven in May of 2008 as the project accomplishment (refer to appendix I for description):

• Competitive cost o Low cost in comparison with unscheduled downtime cost

• Centralize monitoring tasks o Stored and monitored vibration signals at one central location

• Continuously monitor equipment o 24/7 monitored the VTP system

• Increase reliability of operation o Detected one typical problem of the underground component of the

pump • Reduce vibration data collecting time

o Reduced 70% of vibration data collecting time in comparison with manual methods

• Timely alarm as fault signals raise to critical level o Alerted personnel as fault signals exceeded the allowable levels

• Support to predict failures based on the baselines (allowable range) o Setup baseline for typical motor components and predicted the

failure of one typical found signal


11

SYSTEM DESIGN

Design alternatives and selection To acquire vibration data from the VTP, a set of transducers is needed. Transducers

are the devices that convert physical phenomena such as vibration, temperature, and pressure into electric signals which can be processed by a signal analyzer. Based on the techniques of processing, organizing, and interpreting raw data, three concepts were generated: Offline (OF), Online-standalone (OS), and Online-networking (ON) systems.

Offline system The OF system operates similarly to a portable signal analyzer such as CSI 2120

as shown in Figure 1. Vibration data is acquired, displayed and analyzed at a single instrument. Figure 7 illustrates the basic phases of the offline system. Vibration signals (such as bearing defect, flow turbulent, loose iron from stator, etc.) from the vertical turbine pump system are censored by a set of transducers; those signals are then processed in the offline system so as to display the vibration patterns or fault frequencies to the operator (refer to Appendix M for the terminology)

Figure 7 - Offline System

The advantages of the OF system are flexibility, ease of setup and relatively low cost in comparison to the other concepts. The Offline system can be interchangeably utilized as a portable signal analyzer or as a fixed monitoring station; setup for the OF system could be carried out in approximately three hours (based on experiences), and the price of the OF system was estimated at about $5,000.

However, the OF system is limited in the number of channels (usually less than four channels per device), its inability to monitor instantaneous events (events that occur non-periodically), and its inability to monitor a large number of pumps.

Vibration Temperature Pressure

Electrical signals


12

Online-standalone system The OS system separates vibration data acquiring tasks from storing, displaying

and analyzing tasks into two different components. Vibration data acquiring tasks rely on a data acquisition device with Ethernet support (Ethernet support is the ability of the device to connect to the computer network); the acquired data is then concentrated in a database server. Displaying and analyzing tasks are performed in the computer. Figure 8 illustrates the general configuration of the OS system.

Figure 8 - Online-standalone System

The advantage of this system is that it allows the displaying and analyzing center, which is the computer, to locate anywhere within the field. In addition, it expands the capability of the monitoring system to tracking and trending the fault signals at the different phases; this is helpful to the maintenance department to observe the developing of the faults and determine the proper maintenance schedule.

The disadvantage of the system is its limitation of the number of users at a single station. At a monitoring center, only one vibration analyst can use the system; it leads to a shortage of human resource in case the plant has many machines that need to be monitored.


13

Online-networking system The ON system is like the previous OS system except that it divides the data

storage and the monitoring center into two different places. Vibration data from data acquisition devices is concentrated in a database server which can be anywhere in the company’s network. The monitoring center then contacts the database server to extract the vibration data and display it on the computer screen. Figure 9 illustrates the general configuration of the ON system.

Figure 9 - Online-networking System

The advantage of the ON system is expandability; it can be applied to any size plant, from small to large facilities. Furthermore, because the monitoring center and the database server are separated from each other, a plant can have as many monitoring centers as it needs; this ability leads to the optimization of expert skills because vibration experts can work on different monitoring centers to analyze for different sets of pumps.

It is obvious that the disadvantage of this type of system is the high cost compared to the cost of the previous concepts. The cost for the system was estimated to be about $20,000 per pump. The actual price depends on the number of pumps that need to be monitored.


14

Selection Among the three generated concepts, the ON system was chosen. The criteria for

the selection were based on the engineering characteristics in Table 3 (also refer to Appendix J for the Weighted Decision Matrix). According to the Weighted Decision Matrix, the ON system was rated at 7.65 while the OS and OF systems were rated at 6.36 and 2.88 respectively. The huge gap between the ON system and the others can be attributed to its ability to acquire real-time signals (4 points greater than the OF system), trend fault signals (2 points greater than OS system), alert as the fault signals exceed the allowable limit (4 points greater than OF system), and network in a large size plant (5 points greater than the OS system).


15

VTP System Analysis

Overview of the typical failure modes of the VTP

Typical failure modes of the Vertical Turbine Pump (VTP) can be divided into three categories: motor problems, pump problems, and support structure problems. Figure 10 shows the Cause-Effect or Fishbone diagram of typical VTP system failure modes. The motor problems, shown in the top half of the diagram, often relate to the stator, the rotor, or the bearings. The pump problems, shown in the right bottom half of the diagram, often relates to the line shaft, the flow, the journal bearings, the mechanical seal, or the impellers.

Figure 10 - Cause-Effect Diagram of the Typical VTP Failure Modes


16

Typical faults of an induction motor

To properly detect the faults that happen inside the induction motor, it is essential to understand the motor components. Figure 11 shows a schematic of a typical induction motor. It primarily consists of the following:

• Stator: constructed with multi-laminated layers • Rotor: packed with the laminated layers and closed by the end rings • Bearings: two anti-friction bearings to support the rotor • Motor shaft: transfers the rotating motion • Ventilating fan: reduces heat of the motor • Winding (or iron): coil for electric current running through

Any fault that occurs in the motor generates signals that directionally dominate in a specific range of frequencies. Table 4 shows typical faults related to the induction motor. The dominant fault frequencies as well as dominant directions are addressed. Mounting of transducers to acquire vibration data for the motor and vibration severity levels for each type of fault will be discussed later in the Monitoring System Analysis section.

The blue row in the Table 4 dictates the defective rotor bar fault. The dominant frequency of this type of fault happens at rotor bar pass frequency, which equals to the number of the rotor bars multiplies by the turning speed, and associates with twice of the line frequency (60 Hz in US).

Figure 11 - Typical Induction Motor Model


17

Table 4 - Typical Dominant Fault Frequencies of an Induction Motor

Figure 12 illustrates an example of rotor bar defect signals. As the rotor bar defected, it generates the signal at the frequency equal to the number of rotor bar time the turning speed, called Rotor Bar Pass Frequency (RBPF), and surrounded by 120 Hz sideband (refer to Appendix M for the motor parameters)

Figure 12 - An Example of Rotor Bar Defect Signals


18

Typical faults of a vertical turbine pump

Figure 13 illustrates the major components of a typical vertical turbine pump. It primarily consists of the following:

• Column assembly: path of the flowing fluid • Mechanical seal: protect fluid from leaking • Line-shaft: connect motor shaft and pump shaft • Pump shaft: transfer torque to impellers • Bowl assembly: consists of the impeller that impart the fluid to generate

desired pressure • Sleeve bearings: support for the shafts • Coupling: connecting device between shafts

Figure 13 - Typical Vertical Turbine Pump (Courtesy of Sulzer Pump)


19

The fault that occurs in the pump component generates signals in a specific range of frequencies. Table 5 shows the typical failure modes that occur in a vertical turbine pump, which include imbalance, misalignment, looseness, rubbing, cavitations and turbulence.

The blue row shows the defective impeller fault. As the impeller defected, it creates the high level signal at the blade pass frequency, which equals to the number of the blades multiplied by the turning speed, and associates with the turning speed sideband (refer to Figure 14 for the illustration)

Table 5 - Typical Failure Modes of a Vertical Turbine Pump


20

Figure 14 illustrates an example of the impeller defect signals. The rotation of the defected eight-blade impeller generates the signal at the frequency equal to the number of blades times the turning speed, called Blade Pass Frequency (BPF), and surrounded by the turning speed sideband. In this case, the BPF is 158 Hz, associated with the turning speed (TS) sideband, which is 178 Hz (refer to Appendix N for the pump parameters).

Figure 14 - An Example of the Impeller Defect Signals


21

Monitoring System Analysis

To properly acquire and interpret data, a monitoring system has to address three things: collecting data at the proper locations, establishing alarm levels based on the industry standard and/or field experiences, and having a sufficient data acquisition device. The following sections discuss those issues.

Measurement points

According to ISO 5348:1998 (Mechanical vibration and shock – Mechanical mounting of accelerometers), vibration measurement points should be located so that they are significantly responsive to dynamic forces and characterize the overall vibration of the machine. Based on the guideline of ISO 5348, four measurement points should be located at these positions (as shown in figure 15):

• Motor outboard bearing (MOB) (far-end point from the base)

• Motor inboard bearing (MIB) (close-end point from the base)

• Mechanical seal (SEA) • Pipe discharge (DCH).

MOB and MIB points are responsible for monitoring the condition of the motor, whilst SEA and DCH points are used to observe the condition of pump components and flow.

Each point is measured in three Cartesian directions (vertical, horizontal, and axial), except that there are only two directions needed at the discharge and outboard bearing (horizontal and axial). Therefore, the designed monitoring system needs at least 10 channels.

Figure 15 - Recommended Vibration Measurement Points


22

Vibration severity standard

Figure 16 shows a vibration severity criteria chart that was created based on ISO 10816-3, released in 2000. ISO 10816-3 provides the general guideline for determining overall vibration levels for industrial machines with nominal power greater than 15 kW (20 HP) and nominal speeds between 120 RPM and 15000 RPM (2 Hz and 250 Hz). There are four noticeable zones on the chart:

• Green (good) : machine is in perfect condition • Yellow (satisfactory) : machine is in acceptable condition • Orange (unsatisfactory) : machine needs to be service at the next

maintenance routine • Red (unacceptable) : damages have occurred

VTP application is rated at class III with rigid foundation; therefore, the acceptable level ranges from 0.09 to 0.18 ips (in/s). These were used to set up the alarm/alert bands.

Figure 16 - Vibration Severity Criteria


23

Data acquisition system

Figure 17 illustrates the diagram of the data acquisition system. The data acquisition device is the heart of the monitoring system. The actual physical quantities such as vibration, temperature, pressure, sound, etc. are converted into digital data by the transducers so that they can be processed, analyzed, stored and displayed in the computer.

Signal conditioning is the process of conditioning the raw signals into usable signals. Signals from the transducers vary depending on the type of transducer and usually have levels lower than those required for Analog-Digital converter (ADC) input; hence, they need to be amplified. The amplified signals then flow to a set of filters (low pass/high pass/band pass) to eliminate any frequency which is out of the frequency range of interest. The choice of the filter type depends on the application and is commonly fulfilled by setting the jumpers on the data acquisition board.

Data acquisition node is an electronic circuitry to acquire raw data from transducers. The conditioned analog signals from the signal conditioning process are then brought into the acquisition node which typically consists of Analog-to-Digital converter (ADC) and Digital-to-Analog converter (DAC) chips. The ADC is used to convert analog signals into digital signals which could be processed by the computer; the digitized data is stored in the computer. The DAC chip works inversely with the ADC chip; it converts the control signals from the computer into the analog signals so as to trigger the electromechanical relay or the programmable logic control (PLC) system to actuate the actuator (physical actions).

Figure 17 - Data Acquisition System Diagram


24

Component selection

Figure 18 illustrates the detailed component diagram of the monitoring system (refer to Appendix H for the Bill of Materials); it consists of the following items:

• A set of transducers: 10 industrial standard accelerometers, 100 mV/g sensitivity, were located at four measurement points, as shown in figure 15.

• Data acquisition node: 9901 acquisition circuit board, with 16 channels, 4 triggering channels, RJ45 port, was chosen. Compared to the other popular acquisition devices on the market, 9901 was weighted at 14.5; whilst DI730 and Daqbook2000 were 12.5 and 10.1 respectively (refer to Appendix K for the weight decision matrix)

• Networking: Linksys wireless router, WRT100, was employed to model for the network infrastructure of the monitoring system.

• Data storage and management: SQL server 2000 was used to centrally store the acquired data. SQL server 2000 could be implemented in a wide range depending on the scope of the entrepreneur. SQL server was installed on a server operating system; in this project, Microsoft 2003 server was chosen.

• Monitoring center: dynamic signal analyzing software was customized to display and analyze the condition of the VTP system.


25

Figure 18 - Monitoring System Layout


26

ASSEMBLY AND IMPLEMENTATION The designed monitoring system was implemented as shown in Figure 19. The data

acquisition device (placed in the black box) acquired the vibration data that generated by the VTP, processed and delivered to the data concentration center which was the SQL 2000 database server in Figure 18. The monitoring center (the laptop on the left) was equipped with the monitoring software to extract the vibration data from the data concentration center and display it to the operator. Interconnectivity was carried out by the Linksys network router (the little black box with antenna on the right).

Figure 20 illustrates the implementation of the monitoring system in the field. The picture on the right is the vertical pump which has four transducer mounting points encircled by the white dash-line ovals. The left picture includes the data acquisition device, network router and data concentration center, which is similar to Figure 19.

Figure 19 - Designed Monitoring System Layout

Data acquisition device

Data concentration center

Monitoring center

Network router


27

Figure 20 - Monitoring System in the Field


28

TESTING AND PROOF OF DESIGN

Testing and results

The field test was fulfilled during the week of Apr, 7th to Apr, 13th

1. Collected the vibration data from the good VTP

2008. Following was the major course of the actions:

2. Setup the baseline based on the data of the good VTP 3. Established the alarm levels for the typical faults 4. Collected the vibration data from the bad VTP 5. Checked the alarm functions 6. Checked the trending functions 7. Analyzed the root cause of one found fault 8. Predicted the failure based on the trend line and vibration severity standard

Table 6 shows the faults that were found in the field test. The baseline of each type of fault, used to identify the deviation of the current level of the monitored VTP from the ordinary condition, was established based on the normal VTP. There are four colors used to express a current level: green is normal condition, yellow is alert condition (need attention), orange is critical condition (the fault needs to be fixed), red is failure condition (the component has already failed)

Table 6 - Found Faults of the Tested VTP


29

Proof of Design Cost Effectiveness: Table 7 shows the comparison between the cost of the designed

monitoring system and the total cost caused by the premature failures of the VTPs. The total cost of the project was $16,000 for a single unit of VTP; the estimated cost of ten units is $160,000. According to the Water Flood System Predictive Maintenance Program (WFSPMP) review at the VTU’s client site during years 2000 to 2002, the cost related to the field production craft maintenance, which account for the premature failures of the components and the labor hours, was about $830,000 for the same number of units. This amount came from the Work Order records (refer to Appendix O for the sample of the work order records). The cost of the designed monitoring system only equals to 20% of the cost of the premature failures of the pump and motor components.

Table 7 - Cost Comparison

Cost of project Cost of VTPs’ failures Relative difference

$/10 units ($) %

160,000 830,000 80

Centralize monitoring tasks: As shown in Figure 19, the vibration data was acquired by the data acquisition device, and was transferred to the database server through the network router. This configuration enables the monitoring tasks to be performed in the single monitoring center.

Reduce data collecting time: For a vertical turbine pump, the total time for a good skill vibration analyst using a portable instrument to collect the same amount of vibration data was approximately thirty minutes, while it only required the designed monitoring system 45 seconds. The difference between the two methods was 96%; the project goal to reduce the data collection time by 70% was achieved.

Monitor continuously the VTP: The monitoring system continuously acquired vibration data from the VTP every 45 seconds. The designed monitoring system has the ability to monitor any equipment 24/7. However, due to time constraint during the field test, the tested VTP was only monitored continuously for one hour per each visit (total 4 visits).


30

Increase the reliability of the VTP operation: The monitoring system demonstrated its ability to detect faults that occur at unreachable locations, as it did by detecting an impeller defect. Figure 21 illustrates the signal of the defected impeller. This plot shows that the vibration level of the impeller reached the critical level, about 0.35 inches per second (ips) (the baseline for this type of defect signal is 0.07 ips), the second line from the bottom of the Table 6 shows the current levels of impeller defect signal in three directions). The root cause of this fault was insufficient pump shaft support that led to severe misalignment. Finding the root cause of the problem resulted in corrective action that put in extra spiders to support the long pump shaft.

Figure 21 - Impeller Defect Spectrum


31

Alert as fault signals reach critical level: As shown in Figure 22, the middle plot expresses the spectrum of the misaligned pump shaft, the left plot illustrates the misalignment signal that was developing over time, and the right plot shows the trend line of the signal of the misaligned pump shaft. This trending ability enables an operator to track the development of the fault and predict the failure.

Figure 22 - Sample Plots of Fault Trending Capability


32

PROJECT MANAGEMENT

Schedule

The design phase started in January, 08 with the concept generation and selection. Appendix E shows a Gantt chart of the proposed schedule. Following was the course of major tasks in the winter quarter:

• Generated and selected the concept in week 1 (Jan 07st to Jan 12th

• Investigated the actual VTP system at the field in week 2 (Jan 14 )

th to Jan 17th

• Proof of Design agreement on Jan 18)

th

• Analyzed typical failure modes of a VTP system in week 3( Jan 21

st to Jan 26th

• Designed monitoring system in weeks 4 and 5 ( Jan 28)

th to Feb 8th

• Design freeze on Feb 6)

• Purchased the monitoring system components in weeks 6,7 (Feb 8

th th to Feb

23rd

• Deployed the monitoring system in week 8 (Feb 22)

nd to Feb 29th

• Worked on the winter report in weeks 9,10 (Mar 1)

st to March 14th

• Worked on the oral presentation win week 9 (Mar 7)

th to Mar 11th

Failure modes and baseline prediction database was setup in spring quarter, from March 31

)

st to June 6th

• Setup dominant frequency bands in week 1 (Mar 31

. Major tasks during spring are listed below: st to Apr 6th

• Field test the entire system in week 2 (Apr 7 to Apr 13rd) )

• Analyzed the root cause of a chosen failure mode in week 3 (Apr 14th

• Week 4 was the free week for contingency (Apr 21

to Apr 20th)

st to Apr 27th

• Worked on proof of design in week 5 (Apr 28)

th to May 2nd

• Proved the design agreement to advisor on May 2)

• Worked on preliminary for Spring report during weeks 6,7,8 (May 5

nd th to May

22nd

• Prepared for Tech Expo on May 22)

nd , in weeks 7,8 (May 12th to May 22nd

• Worked on oral presentation in weeks 9,10 (May 30)

th to Jun 6th

• Revised final report, due on Jun 9)

th, in weeks 9,10 (May 24th to Jun 4th

)


33

Budget

The total budget was estimated at about $16,000; however, the actual expense was $525 (refer to Appendix F for the budget). This decreased cost was primarily because MachineXL and Vibratechnica donated the four major components, as listed:

• Data acquisition board: $3,900 by MachineXL • Signal analyzing software: $9,000 by MachineXL • Vibration transducers: $1,850 by Vibratechnica • Magnetic mounting blocks: $360 by Vibratechnica

The remaining expense was for the BNC connector and cable ($85), the acquisition box ($60), the network router ($80) and travelling ($300).

Computer equipment was utilized from Vibratechnica’s facility; therefore, all of the costs related to computer system, such as Windows server, SQL server, computers were waived.


34

CONCLUSION The machinery health monitoring system was designed with the needs of oil

producing and power generating industries to enhance the reliability of vertical turbine pumps in mind. It reduces the data acquiring time by providing the continuous online monitoring function, supports maintenance team to detect and predict its equipment faults by offering the fault tracking and trending functions, and prevents the machinery component failures from happening by presenting the alert function.

The project has not just ended at the VTP monitoring system; it is aiming to the level of machinery expert system. By integrating the advanced database storage technology (Microsoft SQL server) into the system, it enables the faults of many types of machinery to be systematically stored in a single location. As the result, these various fault types from the diverse machines can be then categorized into the groups that have the similar characteristics and formed a machinery expert database.

This designed monitoring system is powerful, potential, and practical because it helps personnel from various levels of machinery expertise in the plants to know their equipment. Not only could it help to answer the “How is our machinery?” question from management board, but it also gives the answers about the “Which components are going to fail?” and “How long will they last?” questions to maintenance team. Timely and correctly responding to those kinds of questions will help the production, operation, and maintenance departments to effectively schedule for their tasks; it results in increasing the reliability of their equipment, reducing the unscheduled downtime, and boosting the productivity.


35

REFERENCES 1. Data Acqusition Instrument, DaqBook/2000 Series [Online] [Cited: Oct 01, 2007.] http://www.iotech.com/vibe.html

2. DI-730 Series Data Acquisition Systems [Online] [Cited: Oct, 2007.] http://www.dataq.com/products/hardware/di730.htm.

3. Agile-Link™ Wireless Data Acquisition System

[Online] [Cited: Sept. 29, 2007.] http://www.microstrain.com/pdf/Shortform%20Wireless%20Ad.pdf

4. Vertical Turbine Pump [Online] [Cited: Sept. 27, 2007.] http://www.seepex.com/cps/rde/xchg/en/hs.xsl/products_e-semi-submersible_pump_range_be_807.html.

5. Sulzer Vertical Pump [Online] [Cited: Sept. 29, 2007.] http://www.sulzerpumps.com/Portaldata/9/Resources/brochures/power/vertical/VerticalPumps.pdf

6. Bellgosset Vertical Turbine Pump [Online] [Cited: Sept. 29, 2007.] http://www.bellgossett.com/productPages/Parts-Vertical-Turbine-Pumps.asp

7. Vertical Pump System, Mr. Davis Lee –Principal Consultant of VTUG [In-person Interview] [Nov 2, 2007]

8. Monitoring System, Dr. Roger Kershaw – Director of MachineXL [Telephone Interview] [Nov 10, 2007]

9. Machine Vibration Simulator, Goosman [MET Senior Project - 2000]

10. Data Acquisition System for a Heat Transfer Experiment, Kumo Jason[MET Senior Project - 2001]

11. ISO 5348: 1998 Mechanical vibration and shock – Mechanical mounting of accelerometers

12. ISO 10816-3: 2000 Mechanical vibration – Evaluation of machine vibration by measurements on non-rotating parts

Appendix A

APPENDICES

Appendix A Research Documents

All DaqBooks include documentation on CDROM, quick start guide, DaqView

software; comprehensive drivers for DASYLab, MATLAB, LabVIEW, Visual Studio, and Visual Studio .NET; and DaqCal software application.

• Analog input, analog output, frequency input, timer output, and digital I/O; all in one compact and portable enclosure

• Built-in Ethernet connection provides continuous streaming to the PC with no data loss

• 16-bit, 200-kHz A/D converter • Operates from -30° to +70°C • Powerable from 10 to 30 VDC, or with included AC adapter • Synchronous analog, digital, and frequency measurements • Trigger modes include analog, digital, frequency, and

software • Virtually infinite pre-trigger buffer • 4 channels of 16-bit, 100-kHz analog output (models /2001

and /2020) • DaqBook/2020 offers convenient front panel connectors for

thermocouple, voltage and frequency measurements all in one box

(1)

High price, $13000 Ethernet connection Only four channels Good Expandability Easy to develop soft wares

http://www.iotech.com/catalog/daq/catdk1.html 10/01/07 DaqBook/2000 Series

http://www.iotech.com/catalog/daq/catdk1.html�

http://www.iotech.com/catalog/daq/catdk1.html�

Appendix A

• NEW Synchronous and Distributed Data Acquisition

• Measurement range of ±10mV to ±1000VDC (or peak AC) over six ranges

• 1000V input-to-output and channel-to-channel isolation

• Perfect for troubleshooting AC or DC motor drive systems. Measure field voltages and currents, control signals, RPM, and more. (Click here to learn more)

• Also for electric motor/generator maintenance and troubleshooting in mills and locomotion

• DI-730s easily replace bulky chart recorders • Replace entire racks of isolation amps, high &

low voltage amps, and data acquisition subsystems with one, portable, lightweight, 9 × 7 × 1½ inch instrument

• 14-bit resolution • Printer Port interface is standard, USB or

Ethernet interfaces are optional • Ethernet Option supports synchronous and

distributed data acquisition

(2)

Acceptable Price, $3400 + $2000 Software Ethernet connection 16 channels Low expandability Low resolution chart

http://www.dataq.com/products/hardware/di730.htm 9/26/05 DI-730 Series Data

http://www.dataq.com/distributed-synchronous-data-acquisition/distributed-synchronous-data-acquisition.html�

http://www.dataq.com/distributed-synchronous-data-acquisition/distributed-synchronous-data-acquisition.html�

http://www.dataq.com/products/hardware/di730_varspeed.htm�

http://www.dataq.com/c_cr/index.htm�

http://www.dataq.com/products/hardware/di730.htm�



Appendix A

+ 4 full differential, 350 Ω or higher (optional bridge completion), 3 single ended inputs (0-3 volts) and internal temperature sensor

+ Transmit real time data from node to PC - rate depends on number of active channels1 channel - 4 KHz, 2 channels - 2 KHz, 3 channels - 1.33 KHz, 4 channels - 1 KHz, 5 channels - 800 Hz, 6 channels - 666 Hz, 7 channels - 570 Hz, 8 channels - 500 Hz

+ Software programmable on differential input channels programmable from40 to 3000 (can be reduced with hardware resistor change)

+ Log up to 1,000,000 data points (from 100 to 65,500 samples or continuous) at 32 Hz to 2048 Hz (8 minutes)

(3)

Wireless censoring Not so difficult to deploy Unavailable pricing info

http://www.microstrain.com/pdf/Shortform%20Wireless%20Ad.pdf 09/29/07 Agile-Link™ Wireless Data

http://www.sulzerpumps.com/Portaldata/9/Resources/brochures/power/vertical/VerticalPumps.pdf�




Appendix A

Seepex semi-submersible pumps of the BE range available in the semi-submersible variants crane suspension, wall-mounting, circular mounting plate with pressure branch on top or on the bottom are suited for draining clarifiers, sumps, tanks, pits and containers of all types. Using gas-tight circular mounting plates, the pumps can be installed in closed systems and thus facilitate complying with the strict environmental protection regulations.

4 semi-submersible variants Submersible depth adapted to the respective

application conditions Convenient to service due to plug-in connection

between rotating unit and drive Conveying capacities: 30 l/h – 300 m³/h | 0.132

USGPM - 1,320 USGPM Pressures: up to 12 bar | 180 PSI (4)

No cost information Widely used in industry Able to handle corrosive and abrasive materials Able to handle fluctuating viscosities and flow rates Submersible depth of 8.5 ft. (2.6 m) No valves to clog or foul

http://www.seepex.com/cps/rde/xchg/en/hs.xsl/products_e-semi-submersible_pump_range_be_807.html, 9/26/07

Vertical Pump, seebex.com

http://www.seepex.com/cps/rde/xchg/en/hs.xsl/products_e-semi-submersible_pump_range_be_807.html�





Appendix A

Performance Range The overall performance range provides for discharge rates of 500 to 70’000 m3/h (2200 U.S. gpm to 308’200 U.S. gpm) and delivery heads of 4 up to 20 m (in 2 stage design up to 40 m). Pressure Range The pumps are designed for pressures up to 10 bar. Temperature Range The pumps are suitable for temperatures ranging from – 40°C to + 85°C. Principal Fields of Application • Water supply systems • Water treatment plants • River and sea water intakes • Cooling pumps in thermal power stations. • Sea water desalination plants • Irrigation and drainage schemes • Booster pumps in storage plants • Dock impounding duties • Petrochemical installations (5)

Both oil and water application Easy to access inside Unlike typical desired model

http://www.sulzerpumps.com/Portaldata/9/Resources/brochures/power/vertical/VerticalPumps.pdf 09/29/07 Sulzer Vertical Pump





Appendix A

Multi-stage Vertical Turbine Pumps with bronze impellers and cast iron bowls. The lineshaft turbine pumps have above-ground discharge with water-lubricated lineshaft bearings. The column pipe coupling has bronze centering spiders with fluted-rubber lineshaft bearings. The bowls are vitra-glass coated in the waterways for improvedefficiencies. Capacities up to 10,000 GPM with heads to 150 feet per stage. Discharge Pipe Properly sized for optimum watervelocities to insure peak hydraulic performance. 2 Discharge Bowl Several discharge sizes available for NPT or flanged pipe. 3 Discharge Bearing Extra long top protected bronze bearing insures positive shaft alignment and stabilization for extended life. 4 Intermediate Bowl Close grained Class 30 cast iron. Water passage glassed for maximum efficiency and abrasion resistance. 5 Impellers Designed for maximum efficiency with wide range hydraulic coverage. Precision balanced for smooth operation. 6 Intermediate Bowl Bearings Reliable long life bronze or rubber bearing. 7 Pump Shaft 100,000 PSI high tensile stainless steel provides strength and excellent corrosion resistance. (6)

Wide range applications Similar to desired model Can be scale down Cost information currently unavailable Clear pump curve

http://www.bellgossett.com/productPages/Parts-Vertical-Turbine-Pumps.asp 09/29/07 Bellgosset Vertical Turbine Pump




Appendix A

(7)

(8)

Appendix B

Appendix B Customer Survey with Results

Appendix C

Appendix C Pareto Analysis of the Customer Survey

20% Vital

Appendix D

Appendix D Quality Functional Deployment Matrix

Note: following table explains the meaning of the items in Engineering Characteristics room of the QFD house

Engineering characteristics

Description

Dynamic range (dB) The ability of the system to distinguish between the highest and the lowest amplitude signals. This feature affects on the ability of the system to acquire high frequency signals (which created by, for an instance, bearing defect or cracking rotor bars)

Number of channels One vibration node may need to be measured in three directions, each direction requires a channel.

Fault trending Ability to trend the fault signal as it occur. This helps to diagnose the early symptoms of the failure as well as to predict the failures

Fault alerting Ability to alert as the fault signal as it occur Event triggering Ability to capture the fault signals and then trigger the data acquiring

process. Real-time data acquiring

Most of current system employs multiplexing technique to acquire data; this won’t allow us to capture the transient signals like cavitations in pipe or EDM in motor. Real-time system will empower us to do these tasks

Networking Allow to organize monitoring system centrally, continuously and independently with physical location of the pump system

Appendix E

Appendix E Proposed Schedule

Appendix F

Appendix F Budget

Appendix G

Appendix G Support Letter

Appendix H

Appendix H Proof of Design Statement

In order to be approved as fully achieved, the following statements will be proved:

1. The system will continuously monitor the vertical turbine pump system (500 HP, 1185 RPM AC induction motor; 2 stages, 1170 RPM vertical turbine pump)

2. All the acquired vibration data will be stored in one central location 3. The data collection time will be reduced by at least 50% compared to the existing

manual data collection methods 4. The system will have an alert in case of fault signals exceeding the norm (ISO 10816) 5. At least one typical failure will be predicted based on ISO standard (10816) and

experiences 6. Total cost of ownership will be less than the existing system and one average

unscheduled downtime cost

Advisor’s signature Date

Student’s signature Date

Appendix I

Appendix I Product Objectives

Customer Features Description Objectives

Competitive cost • Analyze total cost of ownership, depreciation

• Breakeven analysis

Low cost comparing with unscheduled downtime cost

Centralize monitoring tasks

• Store and administer vibration data in an organized database management system (like SQL or Oracle)

• Interact with users at a monitoring center

Store and monitor vibration signals at one location

Continuously monitor equipment

• 24/7 monitor the VTP system Monitor the VTP system at least a day

Increase reliability of operation

• Detect fault signals of the underground components of the VTP such as bowl assembly

• Analyze the root causes of the detected fault signals

Detect one typical problem of the underground component of the pump and analyze the root cause of it

Reduce vibration data collecting time

• Reduce vibration data collecting time comparing with manual methods

Reduce 70% of data collecting time

Timely alert as fault signals exceed critical levels

• Alert responsible personnel to the exceeding levels of the fault signals

Alert at least one critical event

Support to predict failures

• Establish the baselines for each type of possible failures based on ISO 10816

• Track the severity of the fault signals • Predict the possible failures based on

the historical data of the similar VTP system

Setup baseline for typical motor components and predict the failure of one typical found signal

Appendix J

Appendix J Concept Weight Decision Matrix

Appendix K

Appendix K Data Acquisition Node Selection Matrix

Appendix L

Appendix L Bill of Material (BOM)

Appendix M

Appendix M Motor Parameters

Westinghouse, 500 HP, 6 poles, 3 phases, 60 Hz, 4000V,60 Amps

Turning speed, TS = 1185 RPM or 19.75 Hz

Line frequency, LF = 60 Hz (US)

Synchronous speed, Ns = 2xLF / #p = 120/6 = 20 Hz (1200 RPM)

Slip frequency, Fs = Ns – TS = 20 – 19.75 = 0.25 Hz (15 RPM)

Pole Pass Frequency, Fp = #p x Fs = 6 x 0.25 = 1.5 Hz (90 RPM)

Roto Bar Pass Frequency, RBPF = # Rotobar x TS = 106 x 19.75 = 2100 Hz

Motor Outboard Bearing (MOB): SKF 6226

Motor Inboard Bearing (MIB): SKF 29430 E

Fundamental Fault Frequencies of the Motor Bearings

FTF = Fundamental Train Frequency

BPFI = Ball Pass Frequency of the inner race

BPFO = Ball Pass Frequency of the outer race

BSF = Ball Spin Frequency

Pd = Pitch Diameter

Bd = Ball Diameter

Nb = Number of Balls

Θ = Contact Angle

Appendix N

Appendix N Pump Parameters

BHP = 599

Head = 190.4 psig

Capacity = 8500 GPM

Stages = 2

Discharge = 26 psig

Water head = 134 psig

Impeller = 8 blades

Blade Pass Frequency = 158 Hz

Appendix O

Appendix O Sample of the Work Order Records Note: This is one of the twelve pages of the work order records. The total cost at the bottom line is $830,000.

Appendix P

Appendix P Terminology

Signal Conditioner: Outputs from transducer are often very low, thus they must be conditioned to provide signals at the appropriate levels for the analog-to-digital converter. Typically, the signal conditioner must have these functions: amplification, isolation, filtering and excitation.

Amplification: Low-level signals should be weighted to a suitable level to increase the resolution and reduce the noise. This task is performed in the amplification circuit.

Isolation: Signals from the transducers and signals from the other electronic devices, such as computers or data acquisition board itself, must be isolated to protect these devices from damage caused by the high-voltage transient surge of the monitored system.

Filtering: Signals that are out of the range of interest must be eliminated to avoid the noise that can reduce the accuracy of the measurement. Filtering circuit perform this function.

Excitation: Some types of transducers, like vibration transducer…, need power from external source to generate the signals. The signal conditioner performs this function by a set of jumpers.

Analog-to-Digital Converter (ADC): Signals from transducers are analog; they have to be converted into digital form so that the digital processing device could understand. This is the function of ADC chip

Sampling rate: This parameter reflects how fast the conversion is performed. The faster the sampling rate, the more the points are acquired and therefore the better the representation of the original signal.

ADC resolution: The number of bits used to represent the analog signal.

Digital-to-Analog Converter (DAC): DAC chip works in inverse with ADC chip, which is convert digital signals into analog signals. The DAC chip is utilized to send the control signal to actuate the physical devices such as actuators.

FFT: Fast Fourier Transform, the computational method to convert a signal’s time waveform into a frequency spectrum

Windowing: Process of applying a weighting to a waveform signal before computing the FFT in order to minimize leakage which give misleading spectrum levels

Averaging: Process of summing a number of time waveforms, sample by sample, or a number of spectra, frequency by frequency, to obtain a better estimate of the mean properties of a signal in the presence of noise or other interfering signals

Machinery health monitoring system for vertical turbine pump

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