Question

A single-phase one pulse controlled circuit has resistance and counters emf load 200 sin(512t) as the source voltage for a load counter emf of 100 V. the range of firing angle control will be:

1. 120° to 150°
2. 30° to 110°
3. 0° to 30°
4. 30° to 150°

Answer 1

Correct Answer - Option 4 : 30° to 150°

Concept:

Firing Angle Control: 

Firing-angle is the phase angle of the voltage at which the SCR turns on. By controlling the firing angle means managing the point on the AC signal waveform when the SCR is going to be triggered or in other words, the time corresponding to the AC signal waveform when the SCR gate is going to be given DC supply voltage.

The range of firing angle control is θ to π - θ.

Calculation:

200 sin θ = 100

sin θ = 0.5

θ = 30°

Now, π - θ = 180° - 30° = 150° 

So control range will be 30° to 150°