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Experiment No:

Date:

DC SHUNT-MOTOR BRAKE TEST

AIM:

To perform brake test on the DC shunt motor and obtain the performancecharacteristics of the motor.

NAME PLATE DETAIL:

APPA!AT" !E#"I!ED: 

.N$ NAME $%T&E

E'PE!IMENT

!AN(E T)PE #"ALIT)

*. +o,tmeter -/--0 M.C *

1. Ammeter -1-A M.C *

/. !heostat /--23*A *

4. Tachometer Ana,o5ue *

6. Connectin5 7ires

As per!e8uired

T&E$!):

  In this method the motor is sub9ected to direct mechanica, ,oadin5 b attachin5

a brake drum and 7ater coo,ed pu,,e to the motor shaft. A rope or be,t is 7ound the

pu,,e at its t7o ends are connected to t7o sprin5 ba,ances * and 1. The tension of

the be,t can be ad9usted b ti5htenin5 it on the pu,,e. The tan5entia, force on the

pu,,e is e8ua, to the difference of the t7o sprin5 ba,ance readin5s.

  PECI%ICATI$N M$T$! (ENE!AT$!

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Tor8ue on the pu,,e ; <* ̴  1= r k5.m ; >.?*<* ̴ 1= mm.

@here r is the radius of the pu,,e in meters and * and 1 are sprin5 ba,ance

readin5s in ki,o5rams.

  Po7er output ; T7atts.

  @here N ; speed in rpm

  T ; Tour8ue in Nm

  Po7er input <Pin= ; +I 7atts

+ ; motor input 0o,ta5e

I ; motor input current.

  Efficienc <B= ; *--

P!$CED"!E:

*. The connections are made a per the circuit dia5ram.

1. The fie,d !heostat is kept at its minimum resistance 0a,ue.

/. 7itch on the DC 11-0 start the motor s,o7, 7ith the he,p of / point starter

under no ,oad conditions.

4. ad9ustin5 fie,d resistance brin5 the motor to its rated speed.

6. App, the brake b ti5htenin5 the hand,e &* or &1 such that the fi,ed current

does not exceeds the rated 0a,ue.

. Tabu,ate a,, the meter readin5s.

P!ECA"TI$N : *. The motor shou,d not be run on no ,oad because it causes dan5erous speed.

1. Coo, the pu,,e 7hi,e performin5 the experiment b pourin5 7ater into the

brake drum.

/. Take the readin5s 7ithout an para,,ax error.

4. efore s7itch off the supp, does not remo0e entire ,oad on the series motor.

6. Experiment shou,d be carried on 7ithin the ,imits of rated 0a,ues.

. !emember to note the mu,tip,ication factor of meters.

. Connections shou,d be made 7ith correct po,arities.

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?. At the time of startin5F keep the motor fie,d resistance at minimum and

5enerator fie,d resistance at maximum position.

>. Check that the speed of motor is constant throu5hout the experiment.

*-. A0oid ,oose connections.

**. !un the motor 7ithout an ,oad because it is a no,oad test.

*1. After comp,etion of the experiment reduce the ,oad on the motor 5radua,,

and s7itch off the supp,.

!E"LT : 

Efficienc is ca,cu,ated for the 5i0en DC shunt motor under 0arious ,oad

conditions b app,in5 ,oad. And dra7 the characteristics cur0es are obtained.