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Compare ON-OFF Control and Phase Control.
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written 5.4 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. |