Power Electronics

Dynamic equalizing circuit is used for________________?

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Dynamic equalizing circuit is used for________________?

A. equal division of voltage across each thyristor
B. equal division of current through each thyristor in parallel
C. equal division of voltage across each thyristor in parallel
D. equal division of current through each thyristor in series

60 thyrsistors are connected in series and parallel to form a 10 KV and 5.5 KA switch. Each thyristor is rated for 1.2 KV, 1 KA. The no. of parallel path are 6. The efficiency of the switch is______________________?

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60 thyrsistors are connected in series and parallel to form a 10 KV and 5.5 KA switch. Each thyristor is rated for 1.2 KV, 1 KA. The no. of parallel path are 6. The efficiency of the switch is______________________?

A. 76.3 %
B. 91.6 %
C. 83.3 %
D. 90.9 %

Maximum di / dt in a SCR is________?

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Maximum di / dt in a SCR is________?

A. Directly proportional to Vm of supply voltage
B. Inversely proportional to Vm of supply voltage
C. Inversely proportional to L in the circuit
D. Both A and C

A thyristor string is made of a no. of SCR connected in series and parallel. The string have volume and current of 11 KV and 4 KA. The voltage and current rating of available SCRs are 1800 V and 1000 A. For a string efficiency of 90 % let the number of SCRs in series and parallel are a and b respectively. Then the value of a and b will be_____________?

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A thyristor string is made of a no. of SCR connected in series and parallel. The string have volume and current of 11 KV and 4 KA. The voltage and current rating of available SCRs are 1800 V and 1000 A. For a string efficiency of 90 % let the number of SCRs in series and parallel are a and b respectively. Then the value of a and b will be_____________?

A. 5, 7
B. 4, 6
C. 7, 5
D. 6, 4