Assertion (A): The principal of step-up chopper can be employed for the regenerative braking of dc motors.
Reason (R) : The step-up chopper can be employed in regenerative braking only for increasing motor speeds
A dc chopper has a T0N of 1 ms and its frequency is 500 Hz. What will be its duty cycle?
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An RLE load is operating in a chopper circuit from a 500 volts dc source as shown in figure
For the load, L = 0.06H, R=0 Ω an duty cycle of 0.2, what is the chopping frequency to limit the amolitude of load current excursion to 10 A?
Match List-I (Thyristor chopper circuits) wtih List-ll (Characteristics) and select the correct answer using the codes given below the lists:
List-I
A. Current commutated chopper
B. Voltage commutated chopper
C. Load commutated chopper
List-ll
1. Diode in antiparallel with main SCR
2. Used in high power circuits
3. No requirement of any commutating inductor
A chopper circuit shown in figure is initially capacitor stored to supply voltage as shown in figure and SCR T1 is in conduction by drawing constant load current of 20A. The switching frequency is 500Hz. What will be the minimum value of the output voltage?
The chopper circuit as shown the thyristor T operated at a duty ratio of 0.8. What will be the value of critical inductance L for which the current falls to zero
A boost converter feeds a resistive load from a battery source. Switch is operated at 5000 Hz with duty ratio of 0.4
What will be the average source current in steady state
A class C chopper is operated from a 220 V battery. The load Is a dc motor with R = 0.1Ω, L= 10 mH and Eb= 100 V. The duty cycle of the chopper to achieve regenerative braking at the rated current of 10 Ampere would be equal to
Assertion (A) : In dc choppers, it is essential to provide a separate commutation circuitry to commutate the main power SCR.
Reason ( R ) : A chopper is dc equivalent to an ac transformer having continuously variable turns ratio.