2:2

DC injection braking is used on?

The stationary windings of AC motors

What is true of shaded-pole motors?

They have a low starting torque, a low efficiency, and a high noise level

The most common service factor appearing on a motor's name-plate is?

1.15

A 3-phase synchronous motor has 3 stator windings that are?

120 degrees apart

The synchronous speed at which a 4-pole, 60 HZ induction motor operates is?

1800 RPM

Which type of motor can be easily reversed by switching 2 of the leads?

3-phase induction motor

How many motor designs does NEMA designate?

5

In a DC series motor, how much of its full-load torque is developed at starting?

500%

Any exposed live parts must be guarded if they are operating at?

50V or more between terminals

In a split-phase motor, how much greater is the starting current when compared to the full-load current?

6-8 times

The electrical energy required to produce one HP of mechanical energy is?

746 W

Due to the absence of any moving electrical contacts, which type of motor should be used where the motor is exposed to flammable dust or gas?

A squirrel cage induction motor

What is used to protect the motor from overloads and starting failures?

A thermal protector

A 3-phase synchronous motor is started with what?

Amortisseur winding

A 3-phase induction motor may have?

Any number of even poles

The primary method of varying the speed on a DC shunt motor is to adjust the voltage and current on the field winding or the?

Armature

The rotating windings of a DC motor

Armature

What is the name of the motor part that rotates during operation?

Armature/rotor

The circuit conductors between the final overcurrent device protecting the circuit and outlets

Branch circuit

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

Brush

What do you do to determine the horsepower rating of a motor that is already installed and in place?

Check the name-plate data

A device used on electric motors or generators to maintain a unidirectional current

Commutator

Which motor is used where the required starting torque is high and speed control desirable?

Compound

Operation at a substantially constant load for an indefinitely long time

Continuous duty

A device that serves to govern, in some predetermined manner, the electric power delivered to the apparatus to which it is connected

Controller

Which motor is the best installation choice for an application requiring adjustable speeds?

DC motors

Describes the length of operation

Duty

Reconnecting a running motor to act as a generator is known as?

Dynamic braking

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

Equipment

What is located on a motor's name-plate?

FLA rating

The stationary portion of a DC motor that produces the magnetic field

Field poles

What is most likely to use dynamic braking?

Forklifts

For a given number of poles, what determines the speed of an AC motor?

Frequency

What does FLA on a motor name-plate stand for?

Full-load amps

What is the NEMA frame designation for gasoline pump motors?

G

What is used to rate the output capacity?

Horsepower

The duty cycle of a motor

Hours

For a constant-torque load, the HP increases and decrease?

In direct proportion to speed

Which motor operates on the principle of a rotating magnetic field?

Induction motors

The method of braking in which DC is applied to the motor windings after AC is removed is known as?

Injection braking

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

Intermittent duty

A wound rotor motor has been recently put back into service but is now rotating in the wrong direction. After examining the motor, you find that lead L1 is connected to T2, L2 to T3, and L3 to T1. To correct the rotation, you should connect?

L1-T1, L2-T3, and L3-T2. Basically reverse any 2 connections

The code requirements for motor disconnects are covered in?

NEC Article 430 part IX

The speed of an induction motor depends on the power supply frequency and what?

Number of poles

The 2 primary types of motor enclosures classified by NEMA are?

Open and totally enclosed

Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from an overload, short circuit, or ground fault

Overload

Intermittent operation at a substantially constant load for a short and definitely specified time

Periodic duty

The speed of a multi-winding motor is normally changed by?

Reversing any two of the incoming leads

The approximate full-load speed at the rated power line frequency

Revolutions per minute (RPM)

For single-phase motors, the standard rotation, unless otherwise noted, is counterclockwise facing the lead or opposite shaft end

Rotation

The starting torque characteristics of an induction motor are defined by?

Rotor resistance

Which motor is used when there is a wide variation in both torque and speed requirements, such as a blower or hoist?

Series DC motor

The difference between the synchronous speed and the speed of the rotor in an induction motor?

Slip

The wound rotor induction motor is used for?

Speed control and to limit starting current

What is the most popular rotor in use for polyphase AC motors?

Squirrel cage

What is the name of the stationary motor part that produces the magnetic field during operation?

Stator

Which motor provides constant speed from no-load conditions to full-load conditions?

Synchronous motors

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

Synchronous speed

The stationary magnet of a DC motor is represented by?

The field poles

The capacitor-start motor is the single-phase motor type that has?

The highest starting torque

The speed of a 3-phase squirrel cage induction motor is controlled by the frequency of the applied voltage and?

The number of poles

The valve indicated in RPM on the nameplate is?

The rated full-load speed

The multiplier to the name-plate HP rating is called?

The service factor

Operation at varying loads and/or intervals of time

Varying duty

According to NEMA definitions, what is a type of totally enclosed motor?

Water-cooled

A motor enclosure that minimizes the entrance of rain and airborne particles to the electrical parts is considered?

Weather-protected

The NEC requires motor disconnecting means be?

Within sight of the controller location

Which motor should be used for applications that require frequent starts without overheating the motor?

Wound rotor induction motor

According to NEMA definitions, which of the following is a type of motor?

Weather-protected

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

Circuit breaker

An open AC squirrel cage motor that makes use of form-wound coils and an insulation system is known as what?

Sealed

NEC Article 430 covers?

The application and installation of motors

A protective device for assembly as an integral part of a motor or motor compressor that, when properly applied, protects the motor against dangerous overheating due to overload or failure to start

Thermal protector

What was the principle reason for developing the brushless DC motor?

To eliminate communicator problems