Converters for Electric Motors

Cycloconverter

Cycloconverter: A variable frequency supply for feeding a three phase motor can be obtained from a cycloconverter which operates on a 50 Hz supply and provides a variable frequency supply at the output (Fig. 3.105). These are single stage frequency conversion devices which make use of both line commutation as well as forced commutation. The …

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Harmonic Reduction

Harmonic Reduction: The output voltage waveform of an inverter is non-sinusoidal. It contains a rich harmonic content. The Harmonic Reduction cause additional losses and torque pulsations if a three phase motor is used as a load. These torque pulsations pose a problem at low speeds. Therefore it is necessary to improve the voltage waveform of …

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Three Phase Inverter

Three Phase Inverter: The variable frequency required for the speed control of three phase ac motors is obtained from a Three Phase Inverter. To avoid magnetic saturation and to obtain constant flux conditions in the machine, the voltage fed to the motor must also be varied. Therefore an inverter feeding a three phase motor must …

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