0
12kviews
Compare ON-OFF Control and Phase Control.
1 Answer
| written 6.5 years ago by |
| Sr. No. | ON-OFF Control | Phase Control |
|---|---|---|
| 1 | Output Voltage is controlled by controlling the number of ON Cycles 'n' and number of OFF Cycles 'm'. | Output voltage is controlled by controlling the phase angle or firing angle of the thyristor. |
| 2 | Thyristor conducts $180^0$ as it is triggered at $\alpha = 0$ | Thyristor is triggered at some angle depending upon output power. |
| 3 | No harmonic due to the switching at zero crossing instants. | Harmonic are present due to switching at instants other than zero crossing. |
| 4 | Load voltage waveform is not distorted | Load voltage waveform is distorted. Distortion increases with increase in $\alpha$ |
| 5 | Average load voltage and load current is zero | Average load voltage and load current is zero |
| 6 | Load voltage will be equal to full supply voltage or zero.Hence output waveform has high voltage fluctuation. | Supply voltage is applied partially to load.Hence there is less voltage fluctuation. |
| 7 | Applications: Industrial heating, speed control of induction motor erc. | Applications: Heat control, light dimmer, fan regulator. |