Testing of dc machines_I

This presentation will help to understand the objectives of testing, its types and two tests viz.. Brake Test and Swinburne's Test of DC Shunt Motor

1. By,

Rohini Haridas

Assistant Professor,
Dept of Electrical Engineering,

SSGM College of Engineering, Shegaon

2. performance of m/c is as per the designed data or

e If not how much variations are there in the actual
values and calculated values, the difference is so
recorded are within the permissible limits or not?

3. accordingly.

e From testing we can also determine the quality of
materials used.

4. + Indirect Method of Testing

e Regenerative Method of Testing

5. = the machine can be loaded to its full load hence temp.
rise at full load can be actually determined.

" As the output is measured by mechanical system

which can not be so accurate and difficult to load large
machines

7. T = radius Of pulley
(W1-W2)Kg

8. Input to motor

Efficiency of Motor= output/input,

9. Given:
(W1-W2)=38.1Kg

d=63.5cm thus, r=(63.5/2)*10m

N=12 rps=12*60 rpm

1=49 Amp
V=220V

10. Output of the Motor = T*w
=118
=8947.416watt

Efficiency=output/input

= 8947.416/10,780

= 83%

*N)/60 watt

11. N=1300 rpm

I=70Amp

V=420V

d= 1m therefore r=0.5m
T

o/p=?

Efficiency=?

12. Output of the Motor = T*w
47.1 *N)/60 watt
0032.36watt
Efficiency=output/input
= 20032.36/29400

= 68.13%

14. its rated spee
+ Under this condition its
No load line current Io

Field current Ish

Rated voltage V, are recorded

From which either constant los

computed.

15. BASES SOR,
FEIN,

—

3 Point Starter

16. [lao = Io — Ish

EV, *10- tac al

Extra:
Therefore,
stray losses = input on no load — shunt field copper

loss — armature copper loss