AUTOMATIC VOLTAGE REGULATION TECHNOLOGIES |
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| Motorized Variacs : |
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Motor driven variacs are operated to maintain output voltage regulation as shown in diagram. This scheme can handle heavy surge currents frequently used in industrial setting due to high surge capability. On the other hand, it has a slow response (30 volts/sec) and is not suitable for sensitive equipment. In addition, it has substantial maintenance requirements and poor .
Transient suppression. Its slow response limits its effectiveness. |
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| CVT's / Ferro resonant Transformers : |
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Ferroresonant transformer with a neutralizing winding |
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This ‘passive' solution widely used in line conditioners for electronic loads. The transformer is operated in the saturated flux region. As a result, the output waveforms are not sinusoidal (square wave) especially with non-linear loads. The transformer operation can be sensitive to circuit capacitance and frequency deviations. In addition, the output voltage can collapse under heavy loading such as motor starting and high inrush currents. |
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This technique offers good line transient suppression but will not suppress transients generated inside plant. A neutralizing winding can be used to cancel some output harmonics as shown in digram.
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Phase Controlled Regulators : |
This technique uses phase controlled thyristors with LC filter to control output voltage. It has a slow response, high distortion especially with non-linear loads, over sized filters, very poor input line harmonics and will not handle surge currents such as motor starting. This scheme has good line transient suppression but will not suppress transients generated inside plant. |
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