32) The carbon brushes of D.C. machines become shorter by wearing out during the running time of the machine. At which length do you have to change the brushes ?

1/2 of the original length

1/3 of the original length

3/4 of the original length

2/3 of the original length

Answer is:

2/3 of the original length

2 amps

4 amps

10 amps

20 amps

Answer is:

same kilowatt output ratings

drooping voltage characteristics

same percentage regulation

same no load and full load speed

Answer is:

burning of switch contact

sudden loading of the prime mover

mechanical jerk to the shaft

all of the above

Answer is:

Shunt and over compound

Series

Shunt and under compound

Over compound

Answer is: