For constant torque drive armature voltage control speed control method is preferred.
Answer : Speed control by Ward Leonard method gives uniform speed variation in both directions.
Answer : The main disadvantage of the Ward-Leonard control method is high initial cost, high maintenance cost, low efficiency at light loads.
Description : Describe spring control method of producing controlling torque in measuring instrument. Write any two properties required for spring material.
Answer : A)Spring control method: As shown in the figure, the inner ends of the both springs are attahced to the spindle, while outer end of upper spring is attached to the lever and outer ... of spring material: 1.Non Magnetic material 2.Low specific resistance 3.Low temperature coefficient of resistance
Answer : In Ward-Leonard control the lower limit of speed is imposed by residual magnetism of the generator.
Description : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?
Answer : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.