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For constant torque drive armature voltage control speed control method is preferred.

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Answer : Speed control by Ward Leonard method gives uniform speed variation in both directions.

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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 : The main disadvantage of the Ward-Leonard control method is high initial cost, high maintenance cost, low efficiency at light loads.

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.

Description : In an adjustable speed ac drive which quantity gets reduced above rated speed ? (A) developed torque (B) stator frequency (C) reduced starting torque (D) stator current

Answer : In an adjustable speed ac drive which quantity gets reduced above rated speed ? (A) developed torque (B) stator frequency (C) reduced starting torque (D) stator current

Description : The meter which does not have any component in it to provide control torque is (A) Electrodynamometer for current measurement (B) Electrodynamometer for voltage measurement (C) Electrodynamometer for power measurement. (D) Electrodynamometer for power factor measurement.

Answer : The meter which does not have any component in it to provide control torque is Electrodynamometer for power factor measurement.

Answer : For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.

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Answer : Advantages of Spring Control Method: 1) The spring-controlled meters may be used in any position. 2) In some instruments, springs can be used as current leads. 3) As springs are light in weight ... only. 2) Scale is non-uniform. 3) Control weights add to the weight of instrument.

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Answer : Speed torque characteristic of a repulsion induction motor is similar to that of a D.C. compound motor.

Description : Illustrate with neat wiring diagram a single lamp control by two point method.

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Description : Explain spring control method with neat diagram.

Answer : 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 end of ... the springs are twisted in opposite direction to the motion of pointer and produce controlling torque.

Answer : The speed control of universal motor used for sewing machines is by varying the resistance.

Answer : Series motor has the poorest speed control.

Description : Speed control of the motor using TRIAC

Answer : Speed control of the motor using TRIAC:  This basic phase triggering circuit uses the triac in series with the motor across an AC sinusoidal supply. The variable resistor, VR1 is used ... meaning that it may not trigger at the exact same point for each positive and negative half cycle.

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Answer : Field control of DC motor Armature control of DC motor

Description : speed control methods of three phase induction motor?

Answer : Speed control of three phase induction motor

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Answer : The shaft torque of a d.c. motor is less than its armature torque because of rotational losses.

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Answer : The maximum torque of d.c. motors is limited by commutation.

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Answer : Regenerative method of braking is based on that back e.m.f. is equal to the applied voltage.

Answer : Ward-Leonard control is basically a voltage control method.

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Description : What does an electric drive do?

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Answer : open emitter BJT drive circuit:

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Answer : basic gate drive circuit of GTO

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Answer : Scherbius Drive System

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Answer : Advantages of Variable Frequency Drive (VFD)

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