pe lab model viva qns

[susmi k m]

1.compare d char of scr wd power trans

2. define holding current of a thyristr

3. define latching current

4.draw vi chara of scr for 2 gate current

5.thyris is a current controlled device.  true or false

6. wat is the need for isolating gate ckt from power ckt of a thyristr

7.advantage of igbt

8.diff b/w scr nd triac

9.effect of gate current on forward breakover voltage of scr

10. methods of turn on of scr

11.why pulse trigerred preferd for firing of scr

12.expn for average o/p voltage of 1phase full converter

13.compare half controlled nd fully controlled convrtr ckt

14.operatn of step up dc chopper

15.advntge of using free wheeling diode in converter ckt

16.use of free wheeling diode in rl load of 1phase bridge converter

17.power ckt of strp down chopper nd its opertn wd rl load

18.power ckt of igbt based 1phase bridge inverter nd operatn wd waveform

19.commonly used pwm technics for voltage and waveform control of convertr

20.draw scheme for speed control of dc motor using a dc chopper and its opertn

21.speed control scheme for a 3phase im motor using power semicondctr based ckt