DC Chopper Interview Question Answer - 2

1	Which chopper is also called as four quadrant chopper?
	Type E chopper
2	What is meant by RLE load?
	It is simple motor load in which E indicates back emf of the motor.
3	Which chopper is also called as two quadrant chopper?
	Type B chopper and type C chopper
4	Which type of chopper configuration is used in the Jones chopper?
	Type D chopper
5	Which circuit provides commutation for the Jones chopper?
	The auxiliary SCR, capacitor C, diode and auto transformer provide commutation circuit for the Jones chopper.
6	Which circuit provides commutation for the Morgan chopper?
	The capacitor, saturable reactor and diode provide commutation circuit for the Morgan chopper.
7	Comment on the value of the inductance for pre saturation and post saturation of the saturable reactor.
	The value of inductance before saturation of the saturable reactor is high whereas its value is low post saturation.
8	How many thyristors the load commutated chopper consists of?
	Four
9	Describe the advantages of the load commutated chopper.
	Advantages No commutating inductor requires No noise Less costly Low weight It can operate at high frequency therefore minimum requirement of filter Commutates any amount of current
10	Describe the disadvantages of the load commutated chopper.
	Disadvantages High switching losses at high frequency Low efficiency in high power applications The peak voltage is twice the supply voltage but it can be reduced by filtering The voltage across freewheeling diode is twice the supply voltage therefore fast recovery diode must be used.
11	Explain the term : Multi phase chopper
	Multi phase chopper It is a chopper which consists of two or more than two choppers operating at same frequency and proper phase shift
12	Describe the operating modes of the multi phase choppers.
	Operating mode of the choppers Phase shift mode In phase mode
13	Describe the function of source filter in the chopper circuit.
	Function of source LC filter in the chopper circuit The LC filter is connected between supply source and chopper. The LC filter reduces Harmonics Source voltage fluctuation Signal interference Supply distortion
14	State the application of the DC Choppers.
	Applications Marine hoists Speed control of induction motor Traction motor control Battery operated vehicles Trolley car