1Tetar traSC the merw bim should be applied for a periodthe

1.Tetar traSC the merw bim should be applied for a period-the lurwdfiw ofth. SKW 2 In phase controlled rectification power factor PE) Compring with Comparing with the fa Mwave recifer u ing two dides, the dade bridge mtihr haa )Hisher cument carrying c) d) Higher efficiency In a a) o ristor cu troled reactor.tht firing ofthyrnar is to be cuatrelled in thr of d) to 270 5. A single phase ac voltage controller is controlling current in a parely inductive load. If the firing ofthe SCR i.what w bethe cuoduction angle ofthe SCR? c) (2s-a) d) 2 power of a single phase hallridge Compared to a ph halfridge inverter, the out inverter is higher by a factor of a) 12 c) 4 inverter contains 7. The output voltage waveform of a three-phase square-wave a) Only even harmonics b) Both odd and cssn harmonics odd d) Only 8.A three-phase fully-controlled thyristor bridge converter is used as line commutated inverter to feed 50 k W power 420 V de to a three phase, 415 Vi(linel, 50 Hz ac mains. Consider de link current to be constant. The rms current of the thyristor a) 119.05 A b) 7937 A c) 73 A 39.68 A

Solution

1.To turnoff a SCR the reverse bias should be applied for a period ---------- the turn off time of the Scr

ans.option b.longer than

2.In phase controlled rectification power factor

ans.option c.Deteriorates with increase of alpha

3. Comparing with the full wave rectifier using two diodes, the four diode bridge rectifier has the dominant advantage of

ans.option b.lower peak inverse voltage requirement

4.In a thyristor controlled reactor, the firing angle of thyristor is to be controlled in the range of

ans.option c.90 degree to 180 degrees

5.A single phase ac voltage controller is controlling current in a purely inductive load.if the firing angle of the scr is alpha,what will be the conduction angle of the ScR
ans.option a.pi

6.compared to a single phase half bridge inverter,the output power of a single phase full bridge inverter is higher by a factor of

ans.option c.4

7.The output voltage waveform of a three phase square wave inverter contains

ans.option c.only add harmonics

8.option d.39.68A

9.In case of voltage source inverter,free wheeling diode can be avoided for the load

option c.Resistive nature

10.Ac voltage regulators are widely used in

option b.fan drives