Electrical Engineering ⇒ Topic : Auto-transformers
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Gopal
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Auto-transformers. Fig.(a) shows the connection diagram for auto-transformer starting of squirrel-cage induction motors.In this method the reduced voltage is obtained by taking tappings at suitable points from a three-phase auto-transformer. The auto-transformers are generally tapped at the 50, 60 and 80 per cent points, so that adjustment at these voltages may be made for proper starting torque requirements. Since the contacts frequently break large values of current arcing is sometimes quenched effectively by having them assembled to operate in an oil bath.
Fig.(a). Auto-transformer starter. | |
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