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REDESIGN OF SINGLE PHASE INDUCTION MOTOR (SINGLE PHASE TO THREE PHASE CONVERSION)

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Submitted bbyy

A.Rakesh (09245A0203) A.Sai Satyaveer (08241A0249) B.RajendraPrasad (08241A0234)

J.Kapil Bharadwaj (08241A0215) S.Rahul (08241A0232)

Under the Guidance of

KK..VVIINNAAYY KKUUMMAARR AASSSSTT.. PPRROOFFEESSSSOORR

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING GOKARAJU RANGARAJU COLLEGE OF ENGINEERING AND

TECHNOLOGY ( Affiliated to Jawaharlal Nehru Technological University)

HYDERABAD, ANDHRA PRADESH 2012

Department of Electrical and Electronics Engineering GOKARAJU RANGARAJU INSTITUTE OF ENGINEERING & TECH.

(Affiliated to Jawaharlal Nehru Technological University) Hyderabad.

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DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING GOKARAJU RANGARAJU COLLEGE OF ENGINEERING AND

TECHNOLOGY HYDERABAD, ANDHRA PRADESH

CHAPTER 1

INTRODUCTION

The characteristics of single phase induction motors are identical to 3-phase induction motors except that single phase induction motor has no inherent starting torque and some special arrangements have to be made for making itself starting. Though single

phase induction motor is not self-starting we are using it because the 3-phase supply is not present at everywhere.

Especially in domestic purposes single phase induction motors are widely used. In

many electrical appliances namely ceiling fan, refrigerator, washing machines etc . We are

using this type of motor. The main reason behind using it is availability of single phase supply and one more is economical i.e., less costlier in price.

In our project, we are going to redesign an Induction motor. It is converted from single phase to three phase but we are giving three phase supply to it.

Later, the module is connect to DAQ and obtaining the voltages and the phase angles on labview.

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CHAPTER 2 INDUCTION MOTOR BASIC PRINCIPLES

2.1 INTRODUCTION: The characteristics of single phase induction motors are identical to 3-phase

induction motors except that single phase induction motor has no inherent starting torque and some special arrangements have to be made for making it self starting. It follows that

during starting period the single phase induction motor must be converted to a type which is not a single phase induction motor in the sense in which the term is ordinarily used and it becomes a true single phase induction motor when it is running and after the speed and torque have been raised to a point beyond which the additional device may be dispensed with. For these reasons, it is necessary to distinguish clearly between the starting period when the motor is not a single phase induction motor and the normal running condition when it is a single phase induction motor. The starting device adds to the cost of the motor and also requires more space. For the same output a 1-phase motor is about 30% larger than

a corresponding 3-phase motor.

The single phase induction motor in its simplest form is structurally the same as a poly-phase induction motor having a squirrel cage rotor, the only difference is that the

single phase induction motor has single winding on the stator which produces mmf stationary in space but alternating in time, a polyphase stator winding carrying balanced currents produces mmf rotat- ing in space around the air gap and constant in time with respect to an observer moving with the mmf. The stator winding of the single phase motor is disposed in slots around the inner periphery of a laminated ring similar to the 3-phase motor.

2.2 MOTOR PRINCIPLE:

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An electric motor is the one, which converts electrical energy into mechanical

energy. The action is based on the principle that when a current carrying conductor is placed in a magnetic field, it experiences a mechanical force. The magnitude of the mechanical force is dependent on the magnetic field strength and current through the conductor. The direction of the mechanical force is also determined by Flemings left hand rule. Thus, when a current carrying conductor is placed in the magnetic field it experiences the mechanical force, and this force rotates the wire. which states that the direction of

induced emf is always opposite to the cause producing it. Suppose the rotor is at rest and 1-phase supply is given to stator winding. The current flowing in the stator winding gives rise to an mmf whose axis is along the winding and it is a pulsating mmf, stationary in space and varying in magnitude, as a function of time,

varying from positive maximum to zero to negative maximum and this pulsating mmf induces currents in the short circuited rotor of the motor which gives rise to an mmf. The currents in the rotor are induced due to transformer action and the direction of the currents is such that the mmf so developed opposes the stator mmf. The axis of the rotor mmf is same as that of the stator mmf. Since the torque developed is proportional to sine of the angle between the two mmf and since the angle is zero, thea net torque acting on the rotor is zero and hence the rotor remains stationary. For analytical purposes a pulsating field can be resolved into two revolving fields of constant magnitude and rotating in opposite

directions as shown in Fig.2.2 and each field has a magnitude equal to half the maximum length of the original pulsating phasor.

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Fig. 2.1 Elementary single phase induction motor

2.3 TYPES OF INDUCTION MOTORS 2.3.1 Single Phase Induction Motor:

There are probably more single-phase ac induction motors in use today than the total of all the other types put together. It is logical that the least expensive, lowest

maintenance type of ac motor should be used most often. The single-phase ac induction motor fits that description. Unlike polyphase induction motors, the stator field in the single-phase motor does not rotate. Instead it simply alternates polarity between poles as the ac voltage changes polarity.

Voltage is induced in the rotor as a result of magnetic induction, and a magnetic field is produced around the rotor. This field will always be in opposition to the stator field (Lenz's law applies). The interaction between the rotor and stator fields will not produce rotation, however. The interaction I shown by the double-ended arrow in figure 2.2, view A. Because this force is across the rotor and through the pole pieces, there is no rotary motion, just a push and/or pull along this line.

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Fig. 2.2 Rotor currents in a single-phase ac induction motor

2.3.4 Three Phase Induction Motor:

Three-phase AC induction motors are widely used in industrial and commercial applications. They are classified either as squirrel cage or wound-rotor motors.

These motors are self-starting and use no capacitor, start winding, centrifugal switch or other starting device. They produce medium to high degrees of starting torque. The power capabilities and efficiency in these motors range from medium to high compared to their single-phase counterparts. Popular applications include grinders, lathes, drill presses, pumps, compressors, conveyors, also printing equipment, farm equipment, electronic

cooling and other mechanical duty applications

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Fig.2.3 Squirrel-cage induction motor

Fig. 2.4 Three phase Space vectors

2.4 SINGLE PHASE INDUCTION STARTING METHODS

The single-phase IM has no starting torque, but has resultant torque, when it rotates at any other speed, except synchronous speed. It is also known that, in a balanced two-phase IM having two windings, each having equal number of turns and placed at a space angle of (electrical), and are fed from a balanced two-phase supply, with two voltages equal in magnitude, at an angle of , the rotating magnetic fields are produced, as in a three-phase IM. The torque-speed characteristic is same as that of a three-phase one, having both starting and also running torque as shown earlier. So, in a single-phase IM, if an auxiliary

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winding is introduced in the stator, in addition to the main winding, but placed at a space angle of (electrical), starting torque is produced. The currents in the two (main and auxiliary) stator windings also must be at an angle of , to produce maximum starting torque, as shown in a balanced two-phase stator. Thus, rotating magnetic field is produced in such motor, giving rise to starting torque. The various starting methods used in a single-phase IM are described here.

Fig.2.5 Windings in an Induction motor

2.4.1 Split Phase Motor

The split-phase motor is also known as an induction start induction run motor. It

has two windings: a start and a main winding. The start winding is made with smaller gauge wire and fewer turns, relative to the main winding to create more resistance, thus putting the start windings field at a different angle than that of the main winding which causes the motor to start rotating. The main winding, which is of a heavier wire, keeps the

motor running the rest of the time.

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FIG.2.6 TYPICAL SPLIT-PHASE AC INDUCTION MOTOR

The starting torque is low, typically 100% to 175% of the rated torque. The motor draws high starting current, approximately 700% to 1,000% of the rated current. The maximum generated torque ranges from 250% to 350% of the rated torque.

Good applications for split-phase motors include small grinders, small fans and blowers

and other low starting torque applications with power needs from 1/20 to 1/3 hp. Avoid using this type of motor in any applications requiring high on/off cycle rates or high torque.

2.4.2 Capacitor Start Motor

This is a modified split-phase motor with a capacitor in series with the start winding to provide a start boost. Like the split-phase motor, the capacitor start motor also has a centrifugal switch which disconnects the start winding and the capacitor when the motor reaches about 75% of the rated speed. Since the capacitor is in series with the start circuit, it creates more starting torque, typically 200% to 400% of the rated torque. And the starting current, usually 450% to 575% of the rated current, is much lower than the split-phase due to the larger wire in the start circuit.

A modified version of the capacitor start motor is the resistance start motor. In this motor

type, the starting capacitor is replaced by a resistor. The resistance start motor is used in applications where the starting torque requirement is less than that provided by the capacitor start motor. Apart from the cost, this motor does not offer any major advantage over the capacitor start motor.

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FIG.2.7 TYPICAL CAPACITOR START INDUCTION MOTOR

They are used in a wide range of belt-drive applications like small conveyors, large blowers and pumps, as well as many direct-drive or geared applications.

2.4.3 Permanent Split Capacitor Motor

A permanent split capacitor (PSC) motor has a run type capacitor permanently connected in series with the start winding. This makes the start winding an auxiliary winding once the motor reaches the running speed. Since the run capacitor must be designed for continuous

use, it cannot provide the starting boost of a starting capacitor. The typical starting torque of the PSC motor is low, from 30% to 150% of the rated torque. PSC motors have low starting current, usually less than 200% of the rated current, making them excellent for applications with high on/off cycle rates. Refer to Fig.2.5 for torque-speed curve.

The PSC motors have several advantages. The motor design can easily be altered for use with speed controllers. They can also be designed for optimum efficiency and High-Power Factor (PF) at the rated load. Theyre considered to be the most reliable of the single-phase motors, mainly because no centrifugal starting switch is required.

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FIG.2.8 TYPICAL PERMANENT SPLIT CAPACITOR MOTOR

Permanent split-capacitor motors have a wide variety of applications depending on the design. These include fans, blowers with low starting torque needs and intermittent cycling uses, such as adjusting mechanisms, gate operators and garage door openers.

2.4.4 Capacitor Start and Run Motor

This motor has a start type capacitor in series with the auxiliary winding like the capacitor start motor for high starting torque. Like a PSC motor, it also has a run type capacitor that is in series with the auxiliary winding after the start capacitor is switched out

of the circuit. This allows high overload torque.

FIG.2.9 TYPICAL CAPACITOR START/RUN INDUCTION MOTOR

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This type of motor can be designed for lower full-load currents and higher efficiency.This motor is costly due to start and run capacitors and centrifugal switch.

It is able to handle applications too demanding for any other kind of single-phase motor. These include wood-working machinery, air compressors, high-pressure water pumps,

vacuum pumps and other high torque applications requiring 1 to 10 hp.

2.5 LAP WINDING:

The calculations are done as per the formulae given below:

The slots/pole/phase=No. of slots/No. of poles/No. of phases.

Pole pitch or coil span=No. of slots/No. of poles.

The angle between 2 consecutive slots=180 electrical degrees/pole pitch or coil span.

Spacing between the 3 phases=120 degrees/Angle between 2 consecutive slots.

Total winding pitch Yr = Yb+Yf = No:of conductors/(No: ofPoles/2). Yr will be an even integer.

Average pitch=(No: of conductors + 2)/No: of poles From this, Yb and Yf are calculated.

Now the winding sequence can be written.

Starting end of coil side of R is placed in slot 1, starting end of coil side Y in slot 3 and

that of B in slot 5.

Complete the winding using front pitch and back pitch.

The fig.2.10 shows the distributed 3-phase winding below.

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fig 2.10 distributed 3 phase winding

CHAPTER 3

COMPONENTS

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3.1 INTRODUCTION: There are several important basic electrical components that are commonly found in the circuits These devices are the fundamental building blocks of electrical and electronic circuits. They can be used and combined with each other and dozens of other devices, in so many different ways. In our projects, we are using different basic components to increase the capacitance, inductance and resistance in the circuit. Some of the basic components are explained in our circuit as follows.

3.2 CAPACITORS: A capacitor is a passive element designed to store energy in its electric field.

Besides resistors, capacitors are the most common electrical components. In electromagnetism and electronics, capacitance is the ability of a body to store charge in an electric field. Capacitance is also a measure of the amount of electric potential

energy stored (or separated) for a given electric potential. A common form of energy storage device is a parallel-plate capacitor. In a parallel plate capacitor, capacitance is directly proportional to the surface area of the conductor plates and inversely proportional to the separation distance between the plates. If the charges on the plates are +q and q, and V gives the voltage between the plates, then the capacitance is given by

The SI unit of capacitance is the farad; 1 farad is 1 coulomb per volt.

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Fig. 3.1 Capacitor

3.3 INDUCTORS:

In electromagnetism and electronics, inductance is that property of an electrical circuit measuring the induced electric voltage compared to the rate of change of the electric current in the circuit. This property also is called self-inductance to discriminate it from mutual inductance, describing the voltage induced in one electrical circuit by the rate of change of the electric current in another circuit. Inductance is caused by the magnetic field generated by electric currents according to Ampere's law. The coefficients of inductance also occur in the expression for the magnetic field energy in terms of the electric currents.

The quantitative definition of the self inductance L of an electrical circuit in SI units (webers per ampere, known as henries) is

where v denotes the voltage in volts and i the current in amperes. The simplest solutions of this equation are a constant current with no voltage or a current changing linearly in time

with a constant voltage.

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The fig. 3.2 shows the inductor.

Fig.3.2 Inductor

3.4 RESISTORS A resistor is a device found in circuits that has a certain amount of resistance.

The most common reason is that we need to be able to adjust the current flowing through a particular part of the circuit.

If voltage is constant, then we can change the resistor to change the current.

I=V/R

If V is constant and we change R, I will be different.

The 2-watt resistors are shown in the fig.3.3.

Fig.3.3 2-Watt Resistors

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The following table 3.4.a shows the resistance values , color of the resistor and tolerance level.

Table 3.4 a Colour coding of resistors and tolerance level values

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3.5 AUTO TRANSFORMER

An autotransformer is an electrical transformer with only one winding. The auto prefix refers to the single coil acting on itself rather than any automatic mechanism. In an

autotransformer portions of the same winding act as both the primary and secondary. The winding has at least three taps where electrical connections are made. An autotransformer can be smaller, lighter and cheaper than a standard dual-winding transformer however the autotransformer does not provide electrical isolation.

Autotransformers are often used to step up or down between voltages in the 110-117-120

volt range and voltages in the 220-230-240 volt range, e.g., to output either 110 or 120V (with taps) from 230V input, allowing equipment from a 100 or 120V region to be used in a 230V region.

The Auto-transformer is shown in the fig.3.4.

Fig.3.4 Auto-transformer

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3.6 FAN STATOR CORE

Singlephase motor has 2 parts. a stator and rotor. the supply is fed to the stator windings.as a result of that,a magnetic field is developed on the stator windings which runs at synchronous speed. this magnetic field is induced on the rotor's windings which produces a torque on it and it starts rotating.this is how a single phase motor rotates. that is partially right but the ac supply has two half cycles +ve and ve

due to which there is magnetic field developed which is alternating in nature due to which the net torque developed in the rotor becomes zero and there is no rotation so to avoid this there is an arrangement of capacitor in the stator to make the rotating magnetic field unidirectional and with a constant magnetic field

Fig.3.5 stator core

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CHAPTER 4 DESIGN OF INDUCTION MOTOR WINDINGS

4.1 Assumptions: Our project is to redesign the single phase induction motor. It is nothing but

converting the single phase motor to three phase motor by maintaining the same size of stator and rotor.

Here, we used a ceiling fan (Capacitor Run Motor) with fixed bearings with Auto-transformer , speed and voltage control system.

There are two phases existing in a single phase winding. One is resistive winding and the other is capacitive winding.

Due to the currents present in the motor, nearly 90 degrees phase shift is created between them. The following fig.4.1 shows the phase shift between the two currents.

Ic 2

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Fig.4.1. 90 degrees phase shift between currents

Due to the phase shift, resultant RMF is created by those currents and the magnitude is generally give by 2. Due to the flux in the rotor, same number of poles are created.

Based on the density, the torque is produced on the rotor. In a three phase motor , there is some difference in winding system. It is of distributed type

winding.

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Physically 120 degrees phase shift and currents also have 120 degrees time phase shift. Due to this, 1.5 RMF is produced in the air gap. It is more than the single phase RMF value.

So, the torque production is comparatively more in three phase motor. It is a high starting torque device when compared with single phase motor. Hence we want to produce the single phase supply to the three phase running induction motor.

The concept is achieved by placing basic components like Inductor, capacitor and resistors.

We have taken a fan stator core which had 2-phase winding. There were 28 slots in within the stator.

By using 3-phase distributed winding , arrangement of 24 slots for 3-phase winding is done.

Total 24 slots , 8-poles. Slot/ pole =24/8 = 3 Slot/pole/phase = 3/3=1 We arranged the winding in 24 slots and similarly a 3-phase winding.

Poles 1 2 3 4 5 6 7 8

Phases

R 1 4 7 10 13 16 19 22

Y 2 5 8 11 14 17 20 23

B 3 6 9 12 15 18 21 24

Table 4.1 Number of poles per phase.

By considering three windings as highly capacitive, highly resistive and highly inductive , there was some difference to the circuit.

The first winding is high capacitive winding and it is 88 degrees of lead current. The second winding is high inductive winding and it is 60-70 degrees of lag current. The third winding is highly resistive and is nearly 16 degrees lag.

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capacitive

80 Voltage

50 16 Resistive

Inductive

Fig.4.2 phasor diagram of normal windings

Ic I l Ir

Ic Il Ir Fig.4.3 Genard Pole Fig.4.4 Phase Shifted pole

N N

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z

Ir

90 0 V 130 0 16 o 140o

Fig.4.5 Phase Angles after changing the direction

The RMF is similar to 3-phase RMF but not exact. By changing the direction of current of the resistive winding in one pole, it will get 180 degrees phase shift . The 3-phase RMF is produced. Hence, we used 8-pole double layer copper winding and it has total 24 coils . Each phase has 8-coils.

The fig. 4.6 shows the actual copper winding.

Fig.4.6 Actual copper windings

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4.2 Requirements and Calculations

Our Requirements Preference 1.100V-0.5amp/phase 1 2.200V-0.5amp/phase 2 3.200V-0.8amp/phase 5 4.100V-0.25amp/phase 3 5.200V-0.25amp/phase 4

Practical Parameters: i. Capacitive Winding:

Capacitive Resistive Inductive V I V I V I

1V 0.13 5 0.04 10 0.13 3V 0.33 10V 0.1 20 0.26 5V 0.33 20 0.19 30 0.4

8.3V 0.84 30 0.28 40 0.52 10V 0.96 40 0.68 50 0.64

50 0.46

Table.4.1 Capacitive winding parameters

Resistive Winding Induced EMF:

E=4.44*60*200* [per pole] ET=E*8

Z=70+j20.42 I = (V-E)/Z Capacitive Winding:

E=4.44*50**55 [per pole] ET=E*8 Z=6.417+j2.60 = 6.923

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Inductive Winding:

E=4.44*50**55 [per pole] Z=28.04+j12.45 I = (V-E)/Z Resistive Coil:

1.100V-0.5amp Design:

0.46 = (50-E)/72.91

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Capacitive Coil:

100V-0.5amp:

0.52 = (5-E)/6.923

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100V-2amp design:

2 = (100 (1*8))/Z ZT = 46 (XC XL) = 45.5 XC = 48.15 C = 66 F 70 F

200V-2amp design:

C = 33 F 35 F

Second order equation for calculating No. of turns:

S = l/A = (0.13/(1.68 * 10-3 * 1.28 * r)) L = N2 o r A/l = (N2 /l) (o r) A 18.7 = (0.1) (o r) A K = 18.7 * 10-12 L = 18.7 * 10-12 (N2 /l) Eb = 4.44 * f * B *A* N

Eb = 0.29 * M 0.3 * M L = 1870 * 10-12 (N2) XL = (587.47) * 10-9 (N2) R = N * (18.7) 0.5 = (100 (0.3) N) / N (18.7m) * (587.42 * 10-9 ) N2 (9.35m) N+ j (293.73 * 10-9) N2 = 100-0.3N (309.35m)N + (293.73 * 10-9) N2 = 100

N=323

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CHAPTER 5 DATA ACQUISITION (DAQ USB-6009)

5.1 EASE OF OPERATION Data acquisition (DAQ) is the process of measuring an electrical or physical phenomenon such as voltage, current, temperature, pressure, or sound. PC-based data acquisition uses a combination of modular hardware and flexible software to transform your standard laptop

or desktop computer into a user- defined measurement or control system. Learn more about each of these components in the sections below.

While each data acquisition system has unique functionality to serve application- specific

requirements, all systems share common components that include signals, sensors, signal conditioning, DAQ hardware, and a computer with software. Data acquisition is the process of sampling signals that measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems (abbreviated with the acronym DAS or DAQ) typically convert analog waveforms into digital values for processing. The components of data acquisition systems include:

Sensors that convert physical parameters to electrical signals. Signal conditioning circuitry to convert sensor signals into a form that can be converted to digital values. Analog-to-digital converters, which convert conditioned sensor signals to digital values.

Data acquisition applications are controlled by software programs developed using various general purpose programming languages such as BASIC, C, Fortran, Java, Lisp, Pascal. COMEDI is an open source API (application program Interface) used by applications to access and control the data acquisition hardware. Using COMEDI allows the same programs to run on different operating systems, like Linux and Windows. Specialized software tools used for building large-scale data acquisition systems include EPICS. Graphical programming environments include ladder logic, Visual C++, Visual

Basic,MATLAB and LabVIEW. We here, have designated to use LabVIEW to write the required program to obtain control

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Source Data acquisition begins with the physical phenomenon or physical property to be measured. Examples of this include temperature, light intensity, gas pressure, fluid flow, and force. Regardless of the type of physical property to be measured, the physical state that is to be

measured must first be transformed into a unified form that can be sampled by a data acquisition system. The task of performing such transformations falls on devices called sensors.

A sensor, which is a type of transducer, is a device that converts a physical property into a

corresponding electrical signal (e.g., a voltage or current) or, in many cases, into a corresponding electrical characteristic (e.g., resistance or capacitance) that can easily be converted to electrical signal.

The ability of a data acquisition system to measure differing properties depends on having sensors that are suited to detect the various properties to be measured. There are specific sensors for many different applications. DAQ systems also employ various signal conditioning techniques to adequately modify various different electrical signals into voltage that can then

be digitized using an Analog-to-digital converter (ADC).

DAQ Hardware

. DAQ hardware is what usually interfaces between the signal and a PC. It could be in the form of modules that can be connected to the computer's ports (parallel, serial, USB, etc.) or cards connected to slots in the mother board. Usually the space on the back of a PCI card is too small for all the connections needed, so an external breakout box is required. The cable between this box and the PC can be expensive due to the many wires, and the required shieldingDAQ cards often contain multiple components (multiplexer, ADC, DAC, TTL-IO, high speed timers, RAM). These are accessible via a bus by a microcontroller, which can run small programs. A controller is more flexible than a hard wired logic, yet cheaper than a CPU so that it is permissible to block it with simple polling loops. For example: Waiting for a trigger, starting the ADC, looking up the time,

waiting for the ADC to finish, move value to RAM,switch multiplexer, get TTL input, let DAC proceed with voltage ramp. Many times reconfigurable logic is used to achieve high

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speed for specific tasks and digital signal processors are used after the data has been acquired to obtain some results. The fixed connection with the PC allows for comfortable compilation and debugging. Using an external housing a modular design with slots in a bus can grow with the needs of the user Not all DAQ hardware has to run permanently connected to a PC, for example intelligent stand-alone loggers and oscilloscopes, which can be operated from a PC, yet they can operatecompletely independent of the PC.

Signals

Signals may be digital (also called logic signals sometimes) or analog depending on the transducer used. Signal conditioning may be necessary if the signal from the transducer is

not suitable for the DAQ hardware being used. The signal may need to be amplified, filtered or demodulated. Various other examples of signal conditioning might be bridge completion, providing current or voltage excitation to the sensor, isolation, and linearization. For transmission purposes, single ended analog signals, which are more susceptible to noise, can be converted to differential signals. Once digitized, the signal can be encoded to reduce and correct transmission errors. A sensor (or transducer) is a device that converts a physical phenomenon into a measurable electrical signal, such as voltage or current. The following table shows a short list of some

common phenomena and the transducers used to measure them. Transducers convert physical phenomena into measurable signals; however, different signals need to be measured in different ways. For this reason, it is important to understand the different types of signals and their corresponding attributes. Signals can be categorized into two groups: analog and digital.

Signal Conditioning

Sometimes transducers generate signals too difficult or too dangerous to measure directly with a data acquisition device. For instance, when dealing with high voltages, noisy

environments, extreme high and low signals, or simultaneous signal measurement, signal conditioning isessential for an effective data acquisition system. It maximizes the accuracy of a system,allows sensors to operate properly, and guarantees safety. Amplification Amplifiers increase voltage level to better match the analog-to-digital converter (ADC) range, thus increasing the measurement resolution and sensitivity.

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In addition, using external signal conditioners located closer to the signal source, or transducer, improves the measurement signal-to-noise ratio by magnifying the voltage level before it is affected by environmental noise.

Attenuation

Attenuation, the opposite of amplification, is necessary when voltages to be digitized are beyond the ADC range. This form of signal conditioning decreases the input signal amplitude so that the conditioned signal is within ADC range. Attenuation is typically necessary when measuring voltages that are more than 10 V.

Isolation

Isolated signal conditioning devices pass the signal from its source to the measurement

device without a physical connection by using transformer, optical, or capacitive coupling techniques.

In addition to breaking ground loops, isolation blocks high-voltage surges and rejects high common-mode voltage and thus protects both the operators and expensive measurement equipment.

Filtering

Filters reject unwanted noise within a certain frequency range. Oftentimes, lowpass filters are used to block out high-frequency noise in electrical measurements, such as 60 Hz power.

Another common use for filtering is to prevent aliasing from high-frequency signals. This

can be done by using an antialiasing filter to attenuate signals above the Nyquist frequency.

Excitation

Excitation is required for many types of transducers. For example, strain gages, accelerometers thermistors, and resistance temperature detectors (RTDs) require external voltage or current excitation. RTD and thermistor measurements are usually made with a

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current source that converts the variation in resistance to a measurable voltage. Accelerometers often have an integrated amplifier, which requires a current excitation provided by the measurement device.

Strain gages, which are very-low-resistance devices, typically are used in a Wheatstone bridge configuration with a voltage excitation source.

Linearization

Linearization is necessary when sensors produce voltage signals that are not linearly related

to the physical measurement. Linearization is the process of interpreting the signal from the

sensor and can be done either with signal conditioning or through software. Thermocouples are the classic example of a sensor that requires linearization.

Cold-Junction Compensation

Cold-junction compensation (CJC) is a technology required for accurate thermocouple measurements. Thermocouples measure temperature as the difference in voltage between

two dissimilar metals. Based on this concept, another voltage is generated at the connection between the thermocouple and terminal of your data acquisition device. CJC improves your measurement accuracy by providing the temperature at this junction and applying the

appropriate correction.

Bridge Completion

Bridge completion is required for quarter- and half-bridge sensors to comprise a four

resistor Wheatstone bridge. Strain gage signal conditioners typically provide half-bridge completion networks consisting of high-precision reference resistors. The completion

resistors provide a fixed reference for detecting small voltage changes across the active resistor(s).

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Hardware aspects of DAQ

Data acquisition hardware acts as the interface between a computer and signals from the

outside world. It primarily functions as a device that digitizes incoming analog signals so that the computer can interpret them. Data acquisitions devices typically consist of one or more of the following functions for measuring different types of signals:

Analog inputs measure analog signals

Analog outputs generate analog signals

Digital inputs/outputs measure and generate digital signals Counter/timers count events or generate pulses Multifunction data acquisition boards combine analog, digital, and counter operations on a single device. Data acquisition hardware is offered on several different PC busses. Each bus offers different levels of ease-of-use and performance and are better suited for different applications.

Computer/Software

Unlike traditional instruments, a computer is a required component in a data acquisition

system. Because of this, a user can take advantage of the ever-increasing performance of the computers processor, hard drive, and display for taking measurements, visualizing data, performing analysis, and storing data.

Software

Software is what transforms the PC and the data acquisition hardware into a complete data acquisition, analysis, and presentation tool. Without software to control or drive the hardware, the data acquisition device does not work properly.

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Driver Software

Driver software is the layer of software for easily communicating with the hardware. It forms the middle layer between the application software and the hardware. Driver software also prevents a programmer from having to do register-level programming or complicated

commands to access the hardware functions.

Application Software

The application layer can be either a development environment in which you build a

custom application that meets specific criteria, or it can be a configuration-based program with preset functionality. Application software adds analysis and presentation capabilities to driver software. To choose the right application software, evaluate the complexity of the application, the availability of configuration-based software that fits the application, and the amount of time available to develop the application. If the application is complex or there is

no existing program, use a development environment.

The complete process of the Data Acquisition is as per the following block diagram:

Fig. 5.1a Block diagram showing the entire process of data acquisition

Improved Productivity through Software

One of the biggest benefits of using a PC-based data acquisition device is that you can use software to customize the functionality and visualization of your measurement system to

meet your application needs. When examining the cost of building a data acquisition system, software development often accounts for 25 percent of total system cost. Obtaining easy-to-use driver software with an intuitive application programming interface makes a big impact on completing a project on time and under budget. National Instruments

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provides a wide array of software tools that make you more productive at accomplishing your measurement or

automation tasks.

NI-DAQmx Driver Software NI LabVIEW Graphical Programming

NI-DAQmx Driver Software

NI-DAQmx driver software goes far beyond a basic DAQ driver to deliver increased productivity and performance and is one of the main reasons National Instruments continues to be the leader in virtual instrumentation and PC-based data acquisition. One Interface, Many Programming Languages

NI-DAQmx provides the same interface for many popular programming languages including NI LabVIEW, Visual Studio .NET languages, C, and C++. The functions and properties, as

well as the order of the functions you use, are the same across all languages.

One Interface, Hundreds of Data Acquisition Devices Whether you are developing with a PCI, PCI Express, PXI, PXI Express, USB, Ethernet, or Wireless data acquisition device, the basic NI-DAQmx code is the same across all devices. With a single programming interface, you can easily upgrade or switch hardware without changing your code.

Easy and Powerful Data Acquisition Software NI-DAQmx includes intuitive features to make taking measurements easier, as well as powerful features to give you higher performance and more flexibility.

Fig. 5.2 Ease of Access of NI DAQ

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5.2 ADVANTAGES OVER OTHER CONTROL INTERFACES Advantages of NI DAQ

NI data acquisition devices designed for performance by providing high-performance I/O, industry-leading technologies, and software-driven productivity gains for your application. With patented hardware and software technologies, National Instruments offers a widespectrum of PC-based measurement and control solutions that deliver the flexibility

and performance that your application demands. For more than 25 years, National Instruments has served as more than just an instrument vendor, but as a trusted advisor to engineers and scientists around the world.

High-Performance I/O

Measurement accuracy is arguably one of the most important considerations in designing any data acquisition application. Yet equally important is the overall performance of the system, including I/O sampling rates, throughput, and latency. For most engineers and

scientists, sacrificing accuracy for throughput performance or sampling rate for resolution is not an option. National Instruments wide selection of PC-based data acquisition devices have set the standard for accuracy, performance, and ease-of-use from PCI to PXI and USB to wireless.

High-Accuracy Designs

Many scientists and engineers mistakenly evaluate DAQ device error by just considering thebit resolution of the DAQ device. However, the error dictated by the device resolution, or

quantization error, might account for only a very small amount of the total error in your

measurement result. Other types of errors, such as temperature drift, offset, gain, and nonlinearity

can vary drastically by hardware design. Through years of experience, NI has developed several key technologies to minimize these errors and maximize the absolute accuracy of your measurements.

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Easy Sensor Connectivity with Integrated Signal Conditioning

Traditionally, measuring sensors required separate front-end signal conditioning systems cabled to a data acquisition system. New technologies and miniaturization have enabled the integration of sensor-specific signal conditioning and analog to digital conversion on the

same device. NI DAQ devices with integrated signal conditioning deliver higher-accuracy measurements by eliminating error-prone cabling and connectors and reduce the number of components in a measurement system.

I/O for Any Sensor, Any Bus

The breadth and depth of National Instruments product offering is not available from any other vendor. NI DAQ devices are offered on a variety of common PC-busses including USB, PCI, PCI Express, PXI, PXI Express, Wi-Fi (IEEE 802.11), and Ethernet, with a wide spectrum of measurement types. NIs modular form factors provide interchangeability to meet your specific applications needs and the flexibility for future expansion.

5.3 INTERFACING DAQ WITH LABVIEW NI LabVIEW Graphical Programming

NI LabVIEW is a graphical programming environment that makes it easy to take any measurement from any sensor on any bus. You can automate measurements from several devices, analyze data in parallel with acquisition, and create custom reports all in a matter of minutes with this industry-standard tool. From acquiring one simple measurement to capturing data from a complex 10,000-channel system, LabVIEW can help you acquire, analyze, and log data in less time.

Fig. 5.3 Interfacing with LabVIEW

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Work Faster with a Graphical Approach

With LabVIEW, you develop data acquisition applications using drag-and-drop graphical icons instead of writing lines of text. You can complete programs that take weeks to write with traditional programming languages in hours using LabVIEW, even if you have no

programming experience. An intuitive flowchart representation displays your code in a manner that is easy to develop, maintain, and understand.

Get Started Immediately with Open-and-Run Examples

There is no need to create your entire data acquisition system from scratch. LabVIEW includes several shipping examples for every common measurement task. Hit the ground running with open-and-run programs for virtually any setup, ranging from a simple single-

channel measurement to a high-performance multichannel system featuring advanced timing, triggering, and synchronization across multiple devices.

Create a Professional User Interface in Seconds

LabVIEW helps you quickly create a graphical user interface using hundreds of drag-and-drop controls, graphs, and 3D visualization tools. You can customize the position, size, alignment, scale, and color of these built-in controls in a matter of seconds from a right-

click menu.

LabVIEW also helps you create your own controls or incorporate custom imagery and logos.

5.4 LABVIEW PROGRAMMING Using Configuration-Based Programming

LabVIEW distinguishes Express VIs with large blue icons. When you place an Express VI on the block diagram, a dialog appears so you can configure how the function executes.

After completing the configuration, the LabVIEW development environment writes the necessary code (represented by the Express VI) for you. You can view and modify this code, and you can change the Express VI configuration by simply double-clicking the Express VI icon.

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Fig. 5.4a Input module menu for programming

Consider the task of reading real-world signals into software for analysis. LabVIEW is designed to make integration with hardware for I/O simple and easy thanks to native drivers and support for thousands of instruments. However, even a task that would otherwise take a handful of VIs to execute can be simplified to a single Express VI. The DAQ Assistance

Fig.5.4b DAQ Assistant Initial Analysis

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Express VI prompts you to select the channels you want to send and receive I/O to and

from, and configure parameters such as sample rate, terminal configuration, scales, triggering, and synchronization. You also can preview the data within the interface before saving the configuration.

Express VIs do not offer the same low-level control as VIs, which is why you may prefer to write the code entirely using VIs. New users interested in learning low-level constructs can easily convert an Express VI to the underlying G code by right-clicking the Express VI and selecting Open Front Panel. Normal VIs can do everything an Express VI can do. The

LabVIEW Professional Development System also includes a utility for creating custom Express VIs.

Taking Advantage of Flexible Programming

The combination of multiple programming approaches in a single development environment offers the advantage of reusing existing code and algorithms developed in other languages. It also makes it possible to combine simple, high-level abstractions with

lower-level code that gives you more visibility and control of your application. These abstraction layers represent highly complex operations in simple, easy-to-read representations, but can be coupled with functions that give low-level control over application behavior and hardware interfaces.

Thanks to tight integration with I/O, you can combine these approaches with real-world signals to take advantage of the most recent hardware technology such as multi-core CPUs, FPGAs, and embedded processors.

Signal processing applications developed in LabVIEW make frequent use of basic constructs that are common to all high-level programming languages: for-loops, while-

loops, and case structures. A For Loop repeats a block of code a fixed number of times, a While Loop repeats a block of code as long as a particular condition is true, and a Case

Structure executes one of several blocks of code depending on some selection criterion. After completing this module you will be able to use these three essential structures in your own LabVIEW VIs.

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CHAPTER 6 FINAL HARDWARE IMPLEMENTATION

6.1 INTERFACING THE INDUCTION MOTOR CIRCUIT WITH DAQ The NI DAQ USB-6009 is designated with 8 analog inputs and 2 analog outputs. Although, this DAQ consists of digital input-output ports, analog ports are most desired as of now, as they are the required ports to access the voltage coming in from the temperature sensor. The distribution of the signal ports and their arrangement is as shown below:

Fig. 6.1a Analog Terminal Assignments of USB-60094

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Fig. 6.2 Digital Terminal Assignments

After successfully initializing the DAQ assistant, following control panel can be observed, where all the required control logic can be given-in and also, respective indicators can be allotted, so as to view their working status.

The following figure 6.1d shows the block diagram of the after connecting three phases.

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Fig.6.3 Block diagram of three phases.

6.2 Final Hardware

The following screen shots show the hardware made and the final output on Labview.

Fig.6.4 Hardware to which a Single phase Induction Motor is fixed.

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Fig.6.5 DAQ connected to the Circuit.

Fig.6.6. 3-phase waveform obtained on Labview.

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CHAPTER 7

RESULTS AND CONCLUSIONS

7.1 WORK DONE IN THIS PROJECT: Winding, equal magnitude of current in each phase and phase shift creation are the main criteria of our project. We winded the 3 phase winding in the stator with different format. The first winding is capacitive winding with four layer, the second winding is Inductive two layer winding and the third winding is resistive single layer winding. for get proper resistance. The above windings are used to get proper resistance and inductance values. By using theoretical calculations winded the no .of turns per pole , external components

like inductor, capacitor, resistor. Current phases in the three windings are analyzed on LAB VIEW by interfacing the module using DAQ. A 3-phase waveforms are obtained when the induction motor is running. This shows that the 3-phase RMF is obtained. It is similar to 3 phase RMF but phase difference between is not exactly 120 degrees. It works properly on 70 v ,0.5 amp (25w, 0.6 power factor).

The final output is show in the fig.7.1 below.

Fig.7.1 Final output waveform on LABVIEW software.

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7.2 DIFFICULTIES ENCOUNTERED DURING THE PROJECT:

In our project stator core is main problem. We used single phase motor core for three phase motor winding. It is not our designed stator core.

Actually stator contains 28 slots but we are using only 24 slots based on three phase winding. Due to the formation of flux, density is not uniform. Hence the speed, torque values are less compared to theoretical values.

The inductance and resistance values depend on the number of turn per pole, but for 230V rating required is 425 turns per pole. It is a difficult process to establish in the stator core.

So we are using 60-70 V rated voltage to run the motor. It is the capable value to run the motor in the safe mode.

To control the current magnets in the fan winding we are using external circuits like resistor, inductor and capacitor.

7.3 FUTURE SCOPE:

This project explains the RMF concept of single phase motor. RMF value increases due to three phase winding using single phase supply and the torque improvement of motor. It is practically proved by this experiment. It gives good efficiency and torque compared with present single phase motors.

Hence this model is the future single phase induction motor.

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REFERENCES

WEBSITES

1. www.ieee.org

2. www.wikipedia.org

3. www.allaboutcircuits.com

TEXT BOOKS

1. Electrical Machine Design by A.K. Sawhney

2. Electrical Machines by Dr.P.S.Bhimbra

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APPENDIX A

The following are the materials we have used in the redesigning of single phase induction motor:

1. Enamelled copper

2. Capacitors

3. Inductors

1. EnamelledcopperwireDatasheet

49

2.data sheet

50

2.Aluminium - Electrolytic Capacitors data sheet

Standard Values Type A

UR CR Case size ESR

100 Hz ESR

100Hz tan 100Hz Z 10KHz Rated ripple current Order code

100Hz

x L

20C typ.

20C max.

20C max.

20C max.

85C 105C

[V] [F] [mm] [m] [m] [%] [m] [A] [A] A...

350 10 10 x 30

8800

13200 6

8800

0,1

...10035010030

350 15 10 x 30

7000

10500 6

7000

0,1

...15035010030

350 22 12 x 30

2600

3900 6

2600

0,2

...22035012030

350 33 14 x 37

1500

2250 6

1500

0,3

...33035014037

350 47 16 x 39

1300

1950 6

1300

0,4

...47035016039

350 100 25 x 38

580

870 6

580

0,7

...10135025038

350 220 25 x 49

400

600 6

400

0,9

...22135025049

350 470 35 x 49

120

180 6

120

2,0

...47135035049

450 4,7 10 x 30

10000

15000 6

10000

0,1

...4,745010030

450 10 12 x 30

7000

10500 6

7000

0,1

...10045012030

450 15 14 x 30

4800

7200 6

4800

0,2

...15045014030

450 22 16 x 30

4500

6750 6

4500

0,2

...22045016030

450 33 18 x 39

3800

5700 6

3800

0,2

...33045018039

450 47 21 x 36

1300

1950 6

1300

0,4

...47045021036

450 100 25 x 49

700

1050 6

700

0,7

...10145025049

450 220 30 x 49

400

600 6

400

1,0

...22145030049

500 10 14 x 30

7000

10500 6

7000

0,1

...10050014030

500 15 16 x 39

4800

7200 6

4800

0,2

...15050016039

500 22 18 x 39

4500

6750 6

4500

0,2

...22050018039

500 33 21 x 36

3800

5700 6

3800

0,2

...33050021036

500 47 25 x 38

1800

2700 6

1800

0,4

...47050025038

500 100 30 x 49

800

1200 6

800

0,7

...10150030049

1

1

3.Inductor data sheet

2

2