Electrical World

Q. What is an Electric Drive? A. The entire unit consisting of an electric motor, the energy transmitting shaft and the control equipment is called an electric drive. Q. What are the advantages of electric drives? A. 1. These drives are available in wide range torque, speed and power. 2. Flexible control characteristics. 3. They are adaptable to any type of working conditions 4. They can operate in all the four quadrants of speed torque plane, which is not applicable for other prime movers. 5. The operation is pollution free. 6. Lower noise, less maintenance. 7. Their efficiency is high as no load losses are less Q. What are the different classes of duty? A. continuous duty: Operation at a constant load for long duration of time. Continuous duty, variable load: Sequence of identical duty cycles consisting of periods of operation under load and no load. Short time duty: Operation at a constant load for small period of time followed by rest. Intermittent periodic duty: Sequen...