Induction Motor Experiments

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Laboratory Experiment of Low-cost AC Induction MotorTrainer

Name:Date:Student NoCourse:

!atin"s

EXPERIMENT # 1

Familiarization with the AC Induction Motor Trainer

I. INTRO!CTION

Motor trainers are wildly used in the enhancement of practical skills of studentsaround the world. There are many kinds of motor trainers including DC or AC motor

trainers. AC motor trainers vary in different types mostly dependent on the kind of AC

motor used in the trainer. The type of motor used in this trainer is a single phase capacitorstart induction motor. Motors convert electrical energy to mechanical energy. Single

phase induction motors apply the law of electromagnetic induction. Electromagnetic

induction is the creation of an electric field by a timevarying magnetic field. !n cases of

motor it uses electric field to produce a timevarying magnetic field which causes therotation of the motor. The varying magnetic field is produced by the alternating current

supply through the stator and rotor windings of an induction motor. The stator and rotor

are the main parts of an induction motor. The stator is the stationary part and the rotor isthe rotating part of an induction motor. The stator windings acts as electromagnets that

operates as poles of the motor. The rotor windings will react with the magnetic field of

the stator that will cause the motor to rotate. "ote that the windings of the rotor will also

act as electromagnets. !n simplification of its operation like poles repel and oppositepoles attract# which causes the mechanical rotation.

Singlephase induction motors have no selfstarting tor$ue. Tor$ue is the force

that causes the ob%ect to rotate. This means that a single phase induction motor will start

unless it is manually started# or a starting method is added into it. !n the case of single

phase capacitor start motor it uses a capacitor to produce a starting tor$ue for the motor.&owever# the capacitor cannot stay long in the circuit that is why a centrifugal switch is

used to cut it out of the circuit.

Single phase induction motors should be protected by overloads. 'verload causes

the motor to overheat and it can cause the internal windings of the motor to burn. &eadedto protect the motor from overload basic protection should always be connected to thecircuit of the motor.


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II.O"ECTI$E%

At the end of this activity# the students are e(pected to)*. +amiliari,e with the AC induction motor trainer.

-. earn the basic functions of the different modules of the AC motor trainer.

/. +amiliari,e with the construction of single phase induction motor.0. earn the principle of operation of a single phase induction motor.

1. Connect basic protection and carry out the necessary tests to determine the

parameters of the motor.

III.MATERIA&%

* AC induction motor trainer* Tachometer

* Multimeter

Connecting 2ires

I$.PROCE!RE%

*. 'bserve and memori,e the different parts of the AC motor trainer shown in figure*.


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Fi'ure 1 AC Induction Motor Module(

-. "otice that every module has distinct functions# as we proceed in this e(perimentobserve every modules functions# and e(plain it on the end of the e(periment.

/. 'bserve and memori,e the main parts of the single phase induction motor shown infigure -.

Stator 3otor


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Fi'ure ) "a(ic Motor Part(

0. "otice the stator windings and define the number of poles of the stator.

1. Establish the motor connection as shown in circuit diagram figure /.

Fi'ure * "a(ic Motor Connection

4. Connect the fuse with holder and breaker for the basic protection as shown in circuitdiagram figure 0.


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Fi'ure + Motor "a(ic Protection

5. Make sure that the connections are in correct placement.

6. Connect the meters as shown in the connection in circuit diagram figure 1# with thebasic protection.

Fi'ure , Meter Connection

7. Apply the rated voltage on the stator side and notice the centrifugal switch action# with

this# record the in rush current or 83C9 ock 3otor Current.

*:. 'nce the motor reaches its steady state measure the input voltage# input current andspeed of the motor.

**. Compute for the synchronous speed of the motor.

*-. 3ecord the data and observe its characteristics.


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$.RE%!&T% AN I%C!%%ION

Ta-le 1 Motor Runnin' Parameter(

3C

8A9

;olts 8;9 Ampere 8A9 Synchronous

Speed 8rpm9

Actual Speed

8rpm9

$I.CONC&!%ION

$II.!E%TION%

*. Describe the function and principle of the basic parts of the motor.

-. Compare circuit breaker from fuse in terms of the motor basic protection.

/. As we can see in figure. - e(plain the connection and the use of capacitor forthe motor.

0. Compute for the synchronous speed using the e$uation above and compare the

result with its actual speed.1. State the function of centrifugal switch on the motor.

REFERENCE%

Callahan# 3. Single


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http)==www.ehow.com=list>4/-4/15>singlephaseinductionmotorcharacteristics.html

awrence# 3.

single phase motor are displaced in space by *-:.A single phase current is fed to thewindings so that a resultant rotating magnetic flu( is generated. The rotor starts rotating

due to the induction effect produced due to the relative velocity between the rotor

winding and the rotating flu(.

Singlephase capacitors motors are commonly used as a drive for fans# pumps and

compressors. ?enerally# they are induction machines of the symmetrical rotor cage and

nonsymmetrical two stator windings 8the main winding and au(iliary winding withstarting or running capacitor9 supplied with the same sinusoidal voltage source. !n real

applications# various kinds of loads e(ist. The motor will operate in a steady state at a

fi(ed speed. The response of the motor to any disturbance gives an idea about thestability of the motor load system. This concept helps in $uick evaluation in the selection

of a motor in driving a particular load.

II.O"ECTI$E%

At the end of this activity# the students are e(pected to)

*. Determine the performance characteristic of a given single phase capacitor start

induction motor by conducting noload test.-. Distinguish the difference between noload test and load test.

III.MATERIA&%

* AC induction motor trainer

* Multimeter
http://www.ehow.com/list_6326357_single-phase-induction-motorcharacteristics.htmlhttp://www.ehow.com/list_6326357_single-phase-induction-motorcharacteristics.htmlhttp://www.ehow.com/list_6326357_single-phase-induction-motorcharacteristics.htmlhttp://www.ehow.com/list_6326357_single-phase-induction-motorcharacteristics.html


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* TachometerConnecting 2ires

I$.PROCE!RE%

*. Connect the circuit as shown in figure no.* with the basic protection.-. Make sure that the shaft of the motor is not loaded before you start the motor.

/. Switch on the AC supply 8--:;9.

Fi'ure 1 %in'le Pha(e Induction Motor with "a(ic Protection

0. Measure the parameters 83C# ampere# voltage and speed9 of the motor as shownin figure no.- and record your data.LRC- Locked Rotor Current or in rushcurrent.

Fi'ure ) %in'le Pha(e Induction Motor at No &oad

1. Bsing the same circuit load the motor shaft with a pan belt

4. !nstall the roller and set it on the middle position as shown in figure no./.

Fi'ure * &oad Te(t on %PIM with Roller al0/wa2 Ad3u(ted


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5. ;ary the load by ad%usting the rollers position to the ma(imum level# shown infigure no.0.

Fi'ure + &oad Te(t on %PIM with Roller at Ma4imum Po(ition

6. Measure and record the parameters for procedure 4 to 5.7. ?raph current vs. speed and compare the results.


Ta-le 1 Motor &oadin' Parameter

$olt( 567 &RC 5a7 Am8ere 5a7 Actual

%8eed

5r8m7

%2nchronou(

%8eed5r8m7

No load

&oad 1&oad )

$I.CONC&!%ION

$II.!E%TION%

*. !n conducting no load test observe the current# is there any changes

-. Describe the performance characteristic of the induction motor with load

variation.


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/. Does installing pan belt into the brake drum and motor shaft affects the motorloading 2hy

0. 2hat happened after installing the roller in the pan belt E(plain.1. Does ad%usting the roller deals with the load system of the motor

4. E(plain the relationship of speed vs. current at no load and full load.

REFERENCE%

awrence# 3.


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* Multimeter* Tachometer

Connecting 2ires

I$.PROCE!RE%

*. Connect the circuit of the capacitorstartmotor as shown in +ig. *.

Fi'ure 1 %in'le Pha(e Ca8acitor/(tart Induction Motor Connection

-. Make sure that the basic protection is connected before any motor operation# see

figure -.

Fi'ure ) %in'le Pha(e Ca8acitor/(tart Induction Motor with "a(ic Protection

/. Switch on the AC supply 8--:;9.0. Bsing the Ammeter# ;oltmeter and Tachometer as shown in figure -# measure the

parameters of the motor at no load and at ma(imum load 8roller at ma(imum

position9 then record it on table no.*.1. Connect the circuit of the capacitorstart-runmotor as shown in figure /.


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Fi'ure * %in'le Pha(e Ca8acitor/run Induction Motor Connection

4. Bsing the same procedures stated above connect basic protection to the motor# see+ig.0. Then record the data in table no.-.

Fi'ure + %in'le Pha(e Ca8acitor/run Induction Motor with "a(ic Protection

5. Compare the results gathered.


Ta-le 1 Ca8acitor %tart Motor

$olta'e567 &RC 5a7 Am8ere 5a7 Actual %8eed

5r8m7

NO &OA

&OA

Ta-le ) Ca8acitor %tart/Run Motor

$olta'e567 &RC 5a7 Am8ere 5a7 Actual %8eed

5r8m7

NO &OA


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&OA

$I.CONC&!%ION

$II.!E%TION%

*. 2hat is the purpose of a capacitor that is connected in series with the au(iliary

winding-. 2hat is the use of centrifugal switch in the circuit E(plain.

/. Compare start capacitor from run capacitor in terms of its operation.

0. 2hat happens when the two capacitors namely start capacitor and run capacitorsare connected in parallel

REFERENCE%

Mul%adi# E. Ad%ustable AC Capacitor for Single


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The resultant magnetic flu( contains a rotating component# which interacting withthe rotor# produces the desired starting tor$ue. 2hen the motor speed reaches a

predetermined percentage of the synchronous speed# a centrifugal switch or a relay opensthe au(iliary circuit. At rest# the circuit is closed again# automatically.

There is much information on a speedtor$ue curve to tell the user if the motorwill operate satisfactorily for the intended application. The speedtor$ue curve will allow

the user to determine if the motor has enough starting tor$ue to overcome friction# to

accelerate the load to full running speed# and if it can handle the ma(imum overloade(pected.

Torquelb . ft=HP x5250

rpm Ns=

120

x frequencyno.of poles

Slip=NsN

Ns x100

"s K Synchronous speed 8rpm9

" K Actual speed 8rpm9

II.O"ECTI$E%


*. be able to determine the tor$ue of an induction motor

-. graph the tor$ue K speed characteristic of an induction motor

III.MATERIA&%


* Multimeter* Tachometer

Connecting 2ires

I$.PROCE!RE%

*. Set the capacitorstart motor connection and meters with the basic protection as

shown in +igure no.* and perform a no load test.


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Fi'ure 1 %in'le Pha(e Ca8acitor/(tart Induction Motor with "a(ic Protection

-. Connect the pan belt with the brake drum and motor shaft.

/. !nstall the roller in the middle position as shown in figure no -.

Fi'ure ) &oad Te(t on %PIM with Roller al0/wa2 Ad3u(ted

0. Move the roller to the ma(imum position# shown in figure no./.

Fi'ure * &oad Te(t on %PIM with Roller at Ma4imum Po(ition

1. Measure the voltage# 3C# current# and speed of the motor.

4. Calculate the synchronous speed# percent slip and tor$ue using the actual

measurements. 3ecord your data.5. Bsing the gathered data plot the results and produce a tor$ue speed graph.



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Ta-le 1 Tor9ue : %8eed Parameter(

$olta'e567 &RC 5a7 Am8ere

5a7

%2nchronou(

%8eed 5r8m7

Actual

%8eed

5r8m7

;

%li8

Tor9ue5l-.0t7

No &oad

&oad 1

&oad )

$I.CONC&!%ION

$II.!E%TION%

*. 2hat behavior of the motor current is noticeable during load variation

-. E(plain the relationship of tor$ue and speed./. Differentiate synchronous from actual speed.

0. 'bserve the H slip and actual motor speeds behavior as the motor load is varied.

REFERENCE%

Lennaugh# M. 8-::*# anuary *9# Measurement of induction motor characteristics#

3etrieved August -*# -:*-# www.tomkennaugh.co.uk=cv=work=eleclab.pdf


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EXPERIMENT # ,o'< %tart< and %to8 Motor Control

I.INTRO!CTION

ogging is the momentary operation of a motor for the purpose of accomplishingsmall movements of the driven machine. !t is use for the fre$uent starting and stopping of

a motor for short period of time. !t is the brief closure of a motor circuit to start a motor

from rest. og is use to align and space machine parts# to position a tool accurately# tothread cloth paper# steel and controlled movements.

II.O"ECTI$E%


*. @e familiar with the %og# start and stop operation use in controlling single phase

induction motor.-. Assemble a start# stop# and %og control circuit with a transfer switch interlock.

/. Assemble a standard start and stop with doublecontact %og control circuit.

0. Compare the effectiveness of the two different way motor control operation.

III.MATERIA&%


* Multimeter

Connecting 2ires

I$.PROCE!RE%


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Fi'ure 1 &atchin' Control Circuit


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*:. Monitor the changes that will happen to the motor.**. Turn off the motor supply and open the disconnect switch.

Fi'ure * %tart< %to8 with %elector o' Control Circuit

$.RE%!&T% AN I%C!I%%ION

E(plain the different control method used in this e(periment.

$I.CONC&!%ION%

$II.!E%TION%

*. 2hat is the effect of latching contact to the start push button-. Can the motor be %ogged with short and long periods


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/. @y setting the selector switch to run position while the motor is running# does themotor stop

0. 2ould you consider /way switch as an electrical interlock1. Bsing figure - as the control circuit# with the motor running does the stop button

have to be depressed before the motor can be %ogged

4. Does the motor continue to run after they are both release

REFERENCE%

awrence# 3.


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EXPERIMENT # =

Re6er(e and Forward O8eration

I.INTRO!CTION

3eversing the rotation of electric motors can be done easily with /phase motors.

This can be easily achieved by swapping the connection of any two motor leads. @ut /phase motors are usually found and used for industrial purposes. The ones found and used

in our homes# from water pumps to electric fans# are single phase capacitorstart type

motors. Bnlike /phase motors# reversing the rotation of single phase electric motors isno easy task. Swapping any two motor leads will not result in the reversal of the motor

rotation. Analysis of the motor windings and connections are necessary before any

modification can be done to achieve the desired result. !n order to achieve the forwardand reverse operation of the motor# addition of /poledouble throw toggle switch in thecontrol circuit is necessary. The toggle switch is a manual switch that lets one manually

reverses the direction in which a motor is turning. The switch contacts are open J closed

manually by moving the switch from the off position to the forward or reverse position.

II.O"ECTI$E%


*. @e familiar with the forward and reverse operation use in controlling single phase

induction motor.

-. Assemble a forward and reverse control circuit with the use of a / poledoublethrow toggle switch.

III.MATERIA&%


* MultimeterConnecting 2ires


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I$.PROCE!RE%


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0. Set the toggle switch to the reverse position. E(amine the direction of the motorrotation.

Fi'ure * Forward and Re6er(e Motor Control

$.RE%!&T% AN I%C!I%%ION

E(plain the forward# reverse# and forward reverse operation.

$I.CONC&!%ION%

$II.!E%TION%

*. !s it necessary to use a three pole K double throw switch to achieve the forward

and reverse operation of the motor E(plain your answer.


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-. As the toggle switch allows a manual reversal of the direction of the motor# howdoes the contactor affects the motor operation

/. 2hy does reversing the rotation of a single AC motor is difficult rather than athree phase AC motor

REFERENCE%

awrence# 3. !DA@OJusgIA+O%C"&1S@

Induction Motor Experiments

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