Control of Traction Motors Interview Questions and Answers: 1. The resistors employed for control of traction motors are designed for short-time rating. Why ? Ans. Because control resistors are required only during starting of traction motors. 2. Under what conditions is field weakening adopted for controlling the speed of a dc series traction motor ? …
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Electric Traction Motors Interview Questions and Answers: 1. Why the magnetic circuit of a traction motor is not made of cast iron ? Ans. Because cast iron cannot withstand continuous vibrations but traction motors operate in extremely severe service conditions. 2. Why the traction motor must be small in overall dimensions specially in its overall …
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Thyristor Control of Electric Motors Interview Questions and Answers: 1. Why the thyristor control is preferred over Ward Leonard system of speed control ? Ans. The thyristor control has some distinct advantages over Ward Leonard system of speed control such as low installation cost, ease of maintenance, higher accuracy, greater reliability, quick response, higher efficiency …
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Control Devices for Industrial Motors Interview Questions and Answers: 1. What are the two main applications of a thyratron ? Ans. Two main applications of thyratron are (i) switching and (ii) rectification. 2. Why is series compensating winding employed in amplidyne ? Ans. Compensating winding is connected in series with the power output brush terminals …
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Protection of AC Generators and Motors Interview Questions and Answers: 1. What are the common types of generator faults ? Ans. The common types of faults occurring in synchronous generators are enumerated below. Stator winding faults — phase-to-phase faults, phase-to-earth faults and inter-turn faults. Rotor winding faults — conductor-to-earth faults, open-circuit faults, inter-turn faults. The …
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Variable Reluctance Stepper Motor Working Principle: A Variable Reluctance Stepper Motor Working Principle consists of a single or several stacks of stators and rotors-stators have a common frame and rotors have a common shaft as shown in the longitudinal cross-sectional view of Fig. 10.34 for a 3-stack motor. Both stators and rotors have toothed structure …
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Blocked Rotor Test of Induction Motor: This Blocked Rotor Test of Induction Motor is used to determine the series parameters of the Circuit Model Parameters of an induction motor. The circuit is similar to that of a transformer short-circuit test. Short circuiting the load resistance in the circuit model of Fig. 9.8 corresponds to making …
No Load Test of Induction Motor: In this No Load Test of Induction Motor, the motor is run on no-load at rated voltage and frequency. The applied voltage and current and power input to motor are measured by the metering as per Fig. 9.17. Let the meter readings be Power input = P0 (3-phase) Current …
Motor Protection: Motor Protection – There is a wide range of motors in existence for various purposes. However, the fundamental problems affecting the choice of protection are independent of the type of motor and the type of load to which it is connected. The motors under discussion here are a.c. motors which include synchronous motors …
Important Questions of Characteristics of Electric Motors: Problems of Characteristics of Electric Motors: 1.A 50 hp, 220 V, 1200 rpm dc shunt motor has an efficiency of 85% at full load. The shunt field resistance is 110Ω and the armature circuit resistance is 0.06Ω. This motor is required to drive a load requiring 120% of …
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