Power Electronics Daily Quiz #4

Natural commutation is not possible in which of the following-

1 Rectifiers

2 AC voltage controllers

3 Step down cycloconverter

4 Step up cycloconverter

Which of thw supply wont support natural commutation-

1 Square wave

2 Sinusoidal

3 DC

4 None

Commutation time is the time after which commutation circuit applies reverse voltage across the device after-

1 Anode current has gone below latching current

2 Anode current has gone below holding current

3 Anode current becomes zero

4 Anode current becomes less than rms of rated current

Total Reverse recovery time of scr is made of-

1 Delay+rise+spread time

2 Fall+tail+storage time

3 Dead+rise time

4 None

Which of the following cant be the value of safety factor-

2

20

50

0.5

During commutation failure the device losses control over

1 Forward blocking property

2 Forward conducting property

3 Reverse blocking property

4 Reverse conducting property

Delay time of scr depends on-

1 Structure of scr

2 Gate current or rate of rise of gate 3 current

4 Load parameters

5 None