This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Electric Motors – Dynamic Braking”. 1. Which braking method is the best method for obtaining high braking torque? a) Regenerative braking b) Plugging c) Dynamic braking d) Rheostatic braking 2. The polarity of back e.m.f changes in which of the method? a) … Read more
This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Electric Motors – Regenerative Braking”. 1. Regenerative braking is not possible in a series motor. a) True b) False 2. Regenerative is the best electrical braking among all braking techniques. a) True b) False 3. Full form of SCIM. a) Squirrel cage … Read more
This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motors – Current Source Speed Control”. 1. Calculate the value of the short circuit ratio if the per unit value of synchronous reactance is 1.5 Ω. a) 0.66 b) 0.33 c) 0.17 d) 0.12 2. A higher value of armature reaction … Read more
This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motors – Voltage/Frequency Control”. 1. Calculate the minimum value of the active power in the cylindrical rotor synchronous machine? (Eb represents armature emf, Vt represents terminal voltage, δ represents rotor angle, X represents reactance) a) Eb×Vt×sinδ÷X b) 0 c) Eb2×Vt×sinδ÷X d) … Read more
This set of Electric Drives Questions and Answers for Experienced people focuses on “Induction Motors – Controlling Speed by Adjusting the Supply Frequency”. 1. 40 V, 7 A, 70 rpm DC separately excited motor having a resistance of 0.3 ohms excited by an external dc voltage source of 4 V. Calculate the torque developed by … Read more
This set of Electric Drives Problems focuses on “Induction Motors – Controlling Speed by Adjusting the Stator Voltage”. 1. The stator voltage control method is a part of the slip changing technique. a) True b) False 2. Calculate the value of new slip using the given data: V1=12 V, S1=.1, V2=5. a) 0.576 b) 0.247 … Read more
This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motors – Controlling Speed Using Inductance”. 1. Calculate the voltage regulation in the synchronous machine if the no-load voltage is 12 V and the full load voltage is 15V. a) -20% b) -40% c) -60% d) -80% 2. Calculate the condition … Read more
This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motors Speed Control – Slip Energy Recovery”. 1. In the rotor voltage injection method, when an external voltage source is in phase with the main voltage then speed will ___________ a) Increase b) Decrease c) Remain unchanged d) First increases then … Read more
This set of Electric Drives written test Questions & Answers focuses on “Induction Motors Speed Control – Rotor Voltage Injection”. 1. A 32-pole, 3-phase, 70 Hz induction motor is operating at a speed of 112 rpm. The frequency of the rotor current of the motor in Hz is __________ a) 40.2 b) 46.1 c) 40.1 … Read more
This set of Electric Drives Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motors – Controlling Speed Using Rotor Resistance”. 1. What is the formula for the maximum active power in the cylindrical rotor synchronous machine? (Eb represents armature emf, Vt represents terminal voltage, δ represents rotor angle, X represents reactance) a) Eb×Vt×sinδ÷X b) … Read more
