Q- The main purpose of the commutator & brushes on a DC generator is to
a) transfer generated DC voltage from the armature to the line
b) convert the alternating voltage generated withtin the armature to a direct voltage
c) provide a sliding contact method to excite the field
d) reduece sparking between the armature and the carbon brushes
Q- In diesel generator, increasing the fuel due to drop in load , which will --------------------save machine from damage
A.Limiting load switch
B.Limiting shredded switch
Q- Which of the following statements represents an application of a silicon controlled rectifier?
A. To provide DC power for a main propulsion motor.
B. For use as a voltage reference diode.
C. For sensing flame in an automated burner.
D. To eliminate power supply hum.
Q- AC circuits possess characteristics of resistance, inductance, and capacitance.The capacitive reactance of acircuit is expressed in
Q- A low voltage protection circuit is used in electric motor starting equipment to
A.Trip circuit contractor when the motor overspeed due to low voltage
B. Trip circuit contractor when the motor develops short circuit due to low voltage
C.Allows the motor to restart automatically on restoration of voltage without manual resetting
D.prevent motor from restarting automatically
Q- If an intrinsic semiconductor is doped with a very small amount of boron then the extrinsic semiconductor set formed, the no. of electrons and holes will
B.increase and decrease
D.Decrease and increase