Upgradation Control system of Double Column Vertical Boring and

Turning Mill-01

using

Variable Frequency Drive

Author

Sajid IRan Khan

16F-MS-EE-15

Focal Person

Mr. Habib Ur Rehman Habib

DEPARTMENT OF ELECTRICAL ENGINEERING

FACULTY OF ELECTRICAL ENGINEERING

UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA

JAN-2017

i

Upgradation Control system of Double Column Vertical Boring

and Turning Mill-01

using

Variable Frequency Drive

Author

Sajid IRan Khan

16F-MS-EE-15

A Report submitted in partial fulfillment of the requirement for the visit of

Heavy Mechanical Complex Taxila

Focal Person Mr. Habib Ur Rehman Habib

Lab Engineer, Electrical Engineering

Chairman’s Signature: _____________________________________________

Focal Person’s Signature: ______________________________________________

DEPARTMENT OF ELECTRICAL ENGINEERING

FACULTY OF ELECTRICAL ENGINEERING

UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA

JAN-2017

ii

ABSTRACT

Double Column Vertical Boring and Turning Mill-01 is a universal heavy duty boring

and turning mill, used for machining parts made of steel, cast iron and non-ferrous metals.

For Double Column Vertical Boring and Turning Mill-01, A DC Motor drive is used to

rotate a rounding table for turning and boring of a given job e.g. wheel gear. To Control

the speed of DC motor drive a Ward Leonard control system is used which a lot of

disadvantages such as system is very costly because two extra machines (motor-generator

set) are required and overall efficiency of the system is not sufficient especially if it is

lightly loaded. To provide a best control system for Double Column Vertical Boring and

Turning Mill-01, we referred Variable frequency drive to replace the Ward Leonard

control system. So for that purpose we will replace DC motor with 75KW AC Spindle

Servo Motor and Control its speed and torque through Variable frequency drive.

Keywords: Double Column Vertical Boring and Turning Mill, Variable Frequency Drive

iii

UNDERTAKING

Use the following undertaking as it is.

I certify that research work titled “Upgradation Control system of Double Column

Vertical Boring and Turning Mill-01 using Variable Frequency Drive” is my own work.

The work has not been presented elsewhere for assessment. Where material has been

used from other sources it has been properly acknowledged / referred.

Signature of Student

16F-MS-EE-15

Engr SI Khan

iv

ACKNOWLEDGEMENTS

I humbly thank Allah Almighty, the Merciful and the Beneficent, who gave me health,

thoughts, co-operative people, and enabled me to achieve this goal.

I am highly thankful to focal person Mr. Habib Ur Rehman Habib, Lab Engineer,

Electrical Engineering Department, University of Engineering and Technology Taxila,

for his kind and continuous help, guidance and encouraging attitude during the

preparation of this report, from the start to the completion, he has been generous to spare

his precious time for discussion and doing away with difficulties arising at various stages.

It can safely be assumed that working under his guidance is nothing short than an asset

which will remain a light tower throughout my life.

I am also grateful to Mr. Khalid Mehmood Shah, Manager at Heavy Mechanical

Complex Taxila for giving me access to all relevant Machine and provide all relevant

information about my project.

At the end especially thanks to staff of Electrical Department of Machine Assy. &

Auxiliary Shop for their co-ordination and meaning full guidance during that period.

v

TABLE OF CONTENTS

Abstract ............................................................................................... ………...ii

Acknowledgement .............................................................................................. iii

List of Figures ..................................................................................................... vi

List of Tables ...................................................................................................... vii

Abbreviations ....................................................................................................viii

Chapter I: Introduction ................................................................................... 8

1.1: Double Column Vertical Boring and Turning Mill-01 ........... 8

1.2: Working Operation perform by VBT-01 ................................ 9

Chapter II: Existing Control System for VBT………………………...…..10

2.1: Existing Control System ........................................................ 10

2.2: Block Diagram of Existing Control system .......................... 12

2.3: Other AC Motors using in VBT-01 ...................................... 12

2.4: Block Diagram For Different Motors in VBT ...................... 13

Chapter III: Proposed Control System……………………………….…...14

3.1: Problem Identification ........................................................... 14

3.2: Proposed Solution .................................................................. 14

3.3: Comparison AC Spindle Servo Motor over DC Motor ........ 16

3.4: Variable Frequency Drive ..................................................... 17

3.5: Variable Frequency Drive Operating Principle .................... 17

Chapter IV: Conclusions & Recommendations……………………...…...19

Chapter V: References……………………….…………………..……...20

vi

LIST OF FIGURES

Number Page

Fig 1.1 View of Vertical Boring and Turning Mill-01……………....…..9

Fig 1.2 Different parts of Vertical Boring and Turning Mill-01 ..............10

Fig 2.1 Generator Motor Set ....................................................................11

Fig 2.2 Control Panel of DC Motor Drive ...............................................12

Fig 2.3 View of DC Compound Motor. ...................................................12

Fig 3.1 75KW AC Spindle Servo Motor. ................................................15

Fig 3.2 Small variable-frequency drive. ..................................................17

vii

LIST OF TABLES

Number Page

Table 2.1 Specifications of MG-Set ……………....………….………...11

Table 2.2 Rating DC Compound Motor …… .........................................12

Table 3.1 Specifications of 75KW AC Spindle Servo Motor .............….15

8

CHAPTER 1

Introduction

1.1 Double Column Vertical Boring and Turning Mill-01

Double Column Vertical Boring and Turning Mill-01 is a universal heavy duty boring and

turning mill, used for machining parts made of steel, cast iron and non-ferrous metals. It is

used for tuning cylinders, cones and plane surfaces by means of high speed steel tool or

carbide tool, and is serviceable both for roughing and finishing. Complete view of Double

Column Vertical Boring and Turning Mill-01 is given below in fig 01.

Fig 1.1: View of Double Column Vertical Boring and Turning Mill-01

Type: C5240

Shop: Machine Assy. & Auxiliary Shop

Serial No: 22

Manufactured By: Wuhan Machine Tool Works

9

1.2 Working Operation perform of Vertical Boring and Turning Mill-01

Vertical boring machine is use for large, heavy work parts through large diameters;

frequently the work part diameter is more than its length. The Part is clamp to workable that

rotates relative to machine base. Worktables able to 40 it in diameter are accessible. Typical

boring machine can place and feed several cutting tools at the same time. Tools are mounted

on toll heads that can be fed horizontally and vertically relative to worktable. One or two

heads are mounting on horizontal cross-rail assemble to machine tool housing over the

worktable. Cutting tools mount over the work can be used for lacing and boring. In adding to

tools on cross-rail, one or two extra tool heads can mount on side columns of housing to

enable revolving on outside diameter of work.

Fig 1.2: Different parts of Double Column Vertical Boring and Turning Mill-01

10

CHAPTER 2

Existing Control System for Vertical Boring and Turning Mill

2.1 Existing Control System

The electrical equipment of this machine consists of control desk, three electrical control

cabinets, M-G set etc.

Power Supply 360V, 50Hz

The Drive of the table is realized by means of a generator-motor automobile speed

adjustment system controlled by SCR with the speed of 200-750-1500 r.p.m. The drives of

left & right tool heads are realized by means of AC electrical shaft. The servo speed is 35-618

r.p.m. sufficient protecting interlocks and signal indicating devices are provided for all the

electrical equipment so as to ensure the safety and reliability of the operation.

Ward Leonard control system is introduced by Henry Ward Leonard in 1891.

For DC drive speed control, variable-voltage DC supply needed for speed control of an

industrial DC motor was to generate it with a DC generator. The generator was driven at

fixed speed by an induction motor, and the field of the generator was varied in order to vary

the generated voltage. So for that purpose pulse transformer provide pulse signal to SCR

where SCR will provide required dc voltage to field of generator.

Fig 2.1: Generator Motor Set

11

Table 2.1: Specifications of MG-Set

DC Generator Induction Motor

Type: Z2-101

90 KW

230V, 392A

1450 r.p.m

Separately excited:

110/220 V

Type: J0-94-4

100KW

660/380 V

1450 r.p.m

180 A

Fig 2.2: Control Panel view using SCR to control Speed of DC Motor Drive

Fig 2.3: View of DC Compound Motor

12

Table 2.2: Rating DC Compound Motor

2.2 Block Diagram of Existing Control system

2.3 Other AC Motors using in Vertical Boring and turning Mill-01

Air Pump Motor

Type: JO2-21-2 (3M)

1.5 KW

2850 r.p.m

380 V 3.22A

Lubricating Oil Pump Motor

Type: JO2-41-4 (D2/T2) (4M)

4.0 KW

1440 r.p.m

380 V 8.40 A

Speed Change Box Oil Pump Motor

Type: JO2-22-6 (D2/T2) (5M)

1.1 KW

930 r.p.m

380 V 3.01 A

Cross Rail Travel Motor

Type: JQO2-52-4 (D2) (6M)

10 KW

1450 r.p.m

380 V 20.35

Cross Rail Left Clamping Motor

Type: JO2-22-6 (D2) (7M)

1.1 KW

930 r.p.m

380 V 3.01 A

Cross Rail Right Clamping Motor

Type: JO2-22-6 (D2) (8M)

1.1KW

930 r.p.m

380 V 3.01 A

DC Compound Motor

Type: Z2-111

75 KW

220 V, 387 A

750/1500 r.p.m

Induction

Motor

Dc

Generator

DC Motor

Drive

Control System

(SCR + Pulse Transformer)

13

2.4 Block Diagram of Control Circuit for Different Motors in VBT

ZD Automatic Switch

Dz1-600/330

Compound Trip

Current 250 A

G-1M

A.C Contactor

CJ1-300A/3

Coil Voltage 380 V

ZD 3M Automatic

Switch Dz4-25/330

Compound Trip

Current 25 A

G-3M

A.C Contactor

CJO-20

Coil Voltage 110 V

ZD 4M Automatic

Switch Dz4-25/330

Compound Trip

Current 10 A

G-4M

A.C Contactor

CJ0-20

Coil Voltage 110 V

G-5M

A.C Contactor

CJ0-10

Coil Voltage 110 V

G-6M

A.C Contactor

CJ0-40

Coil Voltage 110 V

G-7M

A.C Contactor

CJ0-10

Coil Voltage 380 V

G-8M

A.C Contactor

CJ1-300A/3

Coil Voltage 380 V

ZD 5M Automatic

Switch Dz4-25/330

Compound Trip

Current 4 A

ZD 6M Automatic

Switch Dz4-25/330

Compound Trip

Current 25 A

ZD 7M Automatic

Switch Dz4-25/330

Compound Trip

Current 4 A

ZD 8M Automatic

Switch Dz4-25/330

Compound Trip

Current 4 A

3M

380V A.C

Circuit Breaker Magnetic Contactor

380/110V

380/110V

380/110V

380/110 380/110

V V

380/110V

380/110V

1M

4M

5M

6M

7M

8M

Motor

14

CHAPTER 3

Proposed Control System

3.1 Problem Identification

For Double Column Vertical Boring and Turning Mill-01, A DC Motor drive is used to rotate

a rounding table for turning and boring of a given job e.g. wheel gear. To Control the speed

of DC motor drive a Ward Leonard control system is used which has following

disadvantages: 1. The system is very costly because two extra machines (motor-generator set) are

required.

2. Overall efficiency of the system is not sufficient especially if it is lightly loaded.

3. Larger size and weight. Requires more floor area.

4. Frequent maintenance.

5. The drive produces more noise.

6. Signal interrupted in case of pulse transformer burn or fault in SCR.

3.2 Proposed Solution

To provide a best control system for Double Column Vertical Boring and Turning Mill-01,

we referred Variable frequency drive to replace the Ward Leonard control system. So for that

purpose we will replace DC motor with 75KW AC Spindle Servo Motor and Control its

speed and torque through Variable frequency drive.

Fig 3.1: 75KW AC Spindle Servo Motor

15

Table 3.1: Specifications of 75KW AC Spindle Servo Motor

3.3 Comparison AC Spindle Servo Motor over DC Motor

AC Spindle Servo Motor

1. Low power output of about 0.5 W to 100 W

2. Efficiency is less about 5 to 20 %

3. Due to absence of commentator maintenance is less

4. Stability problems are less

5. No radio frequency noise

6. Compare to DC servo motor it is relatively stable and smooth operation

7. AC amplifier used have no drift

DC Compound Motor

1. Deliver high power output

2. High efficiency

3. Frequent maintenance required due to commentator.

4. More problems of stability

5 Brushes produce radio frequency noise.

6. It is noisy operation

7. DC amplifier used have a drift

16

3.4 Variable Frequency Drive

A variable-frequency drive (VFD) (also termed adjustable-frequency drive, variable speed

drive, AC drive, micro drive or inverter drive) is a type of adjustable-speed drive used in

electro-mechanical drive systems to control AC motor speed and torque by varying motor

input frequency and voltage. VFDs are used in applications ranging from small appliances to

the largest of mine mill drives and compressors.

However, around 25% of the world's electrical energy is consumed by electric motors in

industrial applications, which are especially conducive for energy savings using VFDs in

centrifugal load service, and VFDs' global market penetration for all applications is still

relatively small. That lack of penetration highlights significant energy efficiency

improvement opportunities for retrofitted and new VFD installations. Over the last four decades, power electronics technology has reduced VFD cost and size and

has improved performance through advances in semiconductor switching devices, drive

topologies, simulation and control techniques, and control hardware and software.

Small variable-frequency drive is shown in fig 07.

Fig 3.2: Small variable-frequency drive

3.5 Variable Frequency Drive Operating Principle

Whilst there are a number of variations in variable frequency drive design; they all offer the

same basic functionality which is to convert the incoming electrical supply of fixed frequency

and voltage into a variable frequency and variable voltage that is output to the motor with a

corresponding change in the motor speed and torque. The motor speed can be varied from

zero rpm through to typically 100-120% of its full rated speed whilst up to 150% rated torque

can be achieved at reduced speed. The motor may be operated in either direction.

Variable frequency drives applied to AC motors are by far the most common. Their basic

design consists of four elements:

Rectifier: the working principle of rectifier is changing the incoming alternating

current (AC) supply to direct current (DC). Different designs are available and these

are selected according to the performance required of the variable frequency drive.

The rectifier design will influence the extent to which electrical harmonics are

induced on the incoming supply. It can also control the direction of power flow.

17

Intermediate circuit: the rectified DC supply is then conditioned in the intermediate

circuit, normally by a combination of inductors and capacitors. The majority of VFDs

currently in the marketplace use a fixed-voltage DC link.

Inverter: the inverter converts the rectified and conditioned DC back into an AC

supply of variable frequency and voltage. This is normally achieved by generating a

high frequency pulse width modulated signal of variable frequency and effective

voltage. Semiconductor switches are used to create the output; different types are

available, the most common being the Insulated Gate Bipolar Transistor (IGBT).

Control unit: the control unit controls the whole operation of the variable frequency

drive; it monitors and controls the rectifier, the intermediate circuit and the inverter to

deliver the correct output in response to an external control signal.

Variable frequency drives are typically 92-98% efficient with 2-8% losses being due to

additional heat dissipation caused by the high-frequency electrical switching and the

additional power required by the electronic components. Equally motors connected to

variable frequency drives experience some additional losses due to heating caused by the

high frequency electrical switching.

18

CONCLUSIONS & RECOMMENDATIONS

For Vertical Boring and Turning Mill-01, A DC Motor drive is used to rotate a rounding table

for turning and boring of a given job e.g. wheel gear. To Control the speed of DC motor drive

a Ward Leonard control system is used which has a lot of disadvantages. To provide a best

control system for Double Column Vertical Boring and Turning Mill-01, we referred

Variable frequency drive to replace the Ward Leonard control system. So for that purpose we

will replace DC motor with 75KW AC Spindle Servo Motor and Control its speed and torque

through Variable frequency drive.

Proposed Control system will provide following advantages:

This will Energy savings.

Elimination of expensive mechanical drive components.

Increased motor longevity.

Reduced power line disturbances.

Reduced risk of motor damage during start up and stop.

19

REFERENCES

Citations 1) Kulkarni, A.B. (Oct 2000). "Energy consumption analysis for geared elevator modernization:

upgrade from DC Ward Leonard system to AC vector controlled drive". Conference Record

of the 2000 IEEE Industry Applications Conference. 4. Institute of Electrical and Electronics

Engineers. pp. 2066–2070.

2) "Electrically propelled Vehicle", H.W. Leonard, US Patent 1121382, originally filed March,

1903

3) Shinners, Stanley M (1998). Modern Control System Theory. Wiley and Sons. p. 202.

ISBN 978-0471249061.

4) Rajput, R.K. (2005). Basic Electrical Engineering. Laxmi Publications Pvt Limited. p. 571.

ISBN 9788170081203. Retrieved 2014-06-14.

5) Datta, A.K. (1973). "Computerless optimal control of Ward Leonard drive system".

International Journal of Systems Science. 4 (4): 671–678. doi:10.1080/00207727308920047.

General references 1) The Editors (Nov 1989). "Technology for Electrical Components". Power Transmission

Design: 25–27.

2) Ward Leonard, H. (1896). "Volts versus ohms - the speed regulation of electric motors". AIEE

Trans. 13: 375–384.

3) Gottlieb, I.M. (1994). "Electric Motors & Control Techniques 2nd Edition". TAB Books.

4) Malcolm Barnes (2003). Practical Variable Speed Drives and Power Electronics. Oxford:

Newnes. pp. 20–21. ISBN 978-0-7506-5808-9.

5) Campbell, Sylvester J. (1987). Solid-State AC Motor Controls. New York: Marcel Dekker, Inc.

pp. 79–189. ISBN 0-8247-7728-X.

6) Jaeschke, Ralph L. (1978). Controlling Power Transmission Systems. Cleveland, OH:

Penton/IPC. pp. 210–215.

7) Siskind, Charles S. (1963). Electrical Control Systems in Industry. New York: McGraw-Hill,

Inc. p. 224. ISBN 0-07-057746-3.

8) NEMA Standards Publication (2007). Application Guide for AC Adjustable Speed Drive

Systems. Rosslyn, VA USA: National Electrical Manufacturers Association (now The

Association of Electrical Equipment and Medical Imaging Manufacturers). p. 4. Retrieved

Mar 27, 2008.

9) Bose, Bimal K. (2006). Power Electronics and Motor Drives : Advances and Trends.

Amsterdam: Academic. p. 22. ISBN 978-0-12-088405-6.

10) Bartos, Frank J. (Sep 1, 2004). "AC Drives Stay Vital for the 21st Century". Control

Engineering. Reed Business Information.

11) Eisenbrown, Robert E. (May 18, 2008). "AC Drives, Historical and Future Perspective of

Innovation and Growth". Keynote Presentation for the 25th Anniversary of The Wisconsin

Electric Machines and Power Electronics Consortium (WEMPEC). University of Wisconsin,

Madison, WI, USA: WEMPEC. pp. 6–10.

12) Jahn, Thomas M.; Owen, Edward L. (Jan 2001). "AC Adjustable-Speed Drives at the

Millennium: How Did We Get Here?". IEEE Transactions on Power Electronics. IEEE. 16

(1): 17–25. doi:10.1109/63.903985

viii

ABBREVIATIONS

HMC: Heavy Mechanical Complex Taxila

VBT: Vertical Boring and Turning Mill

VFD: Variable Frequency Drive

A.C: Alternating Current

D.C: Direct Current

R.P.M: Revolutions per minute