NCCER ELECTRICAL LEVEL 2 MODULE 2 MOTORS: THEORY

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NCCER ELECTRICAL LEVEL 2 MODULE 2 MOTORS: THEORY

AND APPLICATION EXAM QUESTIONS

Actual Qs and Ans - Expert-Verified Explanation -Guaranteed passing score -86 Questions and Answers

-Format: Multiple-choice / Flashcard

Question 1: wye-connected motor

Answer:

A type of motor terminal arrangement in which three coils are connected together and three coils are isolated

Question 2: horsepower

Answer:

The rated output capacity of the motor. It is based on breakdown torque, which is the maximum torque a motor will develop without an abrupt drop in speed.Question 3: An open AC squirrel cage motor that makes use of form-wound coils and an insulation system is known as a(n) _____.

Answer:

sealed windings(type)

Question 4: ___ use dynamic braking.

Answer:

Forklifts

Question 5: Brush

Answer:

A conductor between the stationary and rotating parts of a machine. It is usually made of carbon.

Question 6: Equipment

Answer:

A general term including material, fittings, devices, appliances, fixtures, apparatus, and the like used as a part of, or in connection with, an electrical installation.

Question 7: intermittent duty

Answer:

Operation for alternate intervals of (1) load and no load; or (2) load and rest; or (3) load, no load, and rest.

Question 8: A delta-connected motor has ____.

Answer:

the coils connected in parallel

Question 9: In three-phase motors, the rotor most commonly used is the _____.

Answer:

squirrel cage rotor

Question 10: What type of rotor is most commonly used in an induction motor?

Answer:

Squirrel cage motor Question 11: All motors must have a thermal protector if their voltage rating is greater than

_____.

Answer:

600V-1,000V

Question 12: The letters FLA on a motor nameplate stand for ____.

Answer:

full-load amps

Question 13: A ____ motor has three stator windings that are 120° apart.

Answer:

polyphase Question 14: Periodic duty: (Definition)

Answer:

Intermittent operation at a substantially constant load for a short and definitely specified time.Question 15: The difference between the synchronous speed and the rotor speed is known as ____.

Answer:

Slip

Question 16: synchronous speed

Answer:

The speed of the revolving field of the stator, which is dependent on the supply frequency and number of poles in a stator winding.

Question 17: Most industrial motors are NEMA Design ____.

Answer:

B

Question 18: The code requirements for motor disconnects are covered in ___.

Answer:

430.102

Question 19: Continuous duty

Answer:

Operation at a substantially constant load for an indefinitely long time.Question 20: The electrical energy required to produce 1hp of mechanical energy is _____.

Answer:

746W

Question 21: A wye-connected motor has _____.

Answer:

the coils pointed in series Question 22: To protect the motor from overloads and starting failures, use a ____.

Answer:

thermal protector

Question 23: Circuit breaker

Answer:

A device designed to open and close a circuit by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without injury to itself when properly applied within its rating.

Question 24: With a constant-torque load, the horsepower ____.

Answer:

varies in direct proportion to the speed

Question 25: When using a motor with dynamic braking, ____.

Answer:

electromechanical friction brakes may be required with large loads Question 26: The multiplier to the nameplate horsepower rating is called the _____.

Answer:

service factor Question 27: The starting torque characteristics of a wound-rotor motor are defined by _____.

Answer:

rotor resistance Question 28: The most common service factor appearing on a motor nameplate is ___.

Answer:

1.15