Electrical 2; MOD 2

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A motor that produces 375 watts of power is a​ _____ horsepower motor.

0.5

A​ consequent-pole motor has​ _____ speed(s).

2

The electrical energy required to produce 1hp of mechanical energy is​ _____.

746W

Most industrial motors are NEMA Design​ __________.

B

The NEMA frame designation for gasoline pump motors is​ _____.

G

The code requirements for motor disconnects are covered in​ _____.

NEC Article​ 430, Part IX

The NEC​® section that covers disconnecting means for motors is​ _____.

NEC Section 430.109

The service factor rating is​ _____.

a multiplier related to the horsepower overload the motor can tolerate

The speed of a DC shunt motor is varied by​ _____.

altering the voltage applied to the armature or field winding

A​ three-phase synchronous motor is started with​ a(n) _____.

amortisseur winding

The full load amps​ (FLA) rating of a motor means the​ _____.

amount of current a motor will draw when operating at the nameplate​ voltage, frequency, and horsepower

The name of the motor part that rotates during operation is the​ _____.

armature/ rotor

The part of a DC motor that makes electrical contact with the commutator to provide continuous voltage is the​ _____.

brushes

Which of the following types of​ single-phase induction motors has a start winding that is switched out of the circuit after the motor​ starts?

capacitor start

o determine the horsepower rating of a motor that is already installed and in​ place, _____.

check the nameplate data

motor that has three sets of three leads with continuity between the wires in each set is a​ _____-connected motor.

delta

The NEMA Dimension D of a motor is the​ _____.

distance from the motor feet to the centerline of the shaft

Reconnecting a running motor to act as a generator is known as​ _____.

dynamic braking

The principal reason for developing the brushless DC motor was to​ _____.

eliminate commutator problems

The letters FLA on a motor nameplate stand for​ _____.

full-load amps

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

injection braking

The synchronous speed of a motor is determined by frequency of the applied voltage and the​ _____.

number of magnetic poles

The speed of an induction motor depends on the power supply frequency and the​ _____.

number of poles

The two primary types of motor enclosures classified by NEMA are​ _____.

open and totally closed

what is on a motor nameplate?

power factor, efficiency, torque, and current are at rated voltage and frequency

Large DC motors require that a starting​ _____ be placed in series with the motor armature.

resistance

The starting torque characteristics of a​ wound-rotor motor are defined by​ _____.

rotor resistance

An open AC squirrel cage motor that makes use of​ form-wound coils and an insulation system is known as​ a(n) _____.

sealed windings

When there is a wide variation in both torque and speed​ requirements, such as a blower or a​ hoist, use a​ _____.

series DC motor

The multiplier to the nameplate horsepower rating is called the​ _____.

service factor

Given the speed and torque characteristics of shunt and series DC​ motors, which one would be the better suited to the varying loads of an​ escalator?

shunt

The DC motor that provides good speed control but low starting torque for large loads is the​ _____ motor.

shunt

In​ three-phase motors, the rotor most commonly used is the​ _____.

squirrel cage rotor

A synchronous motor uses​ a(n) _____ to obtain starting torque.

squirrel cage winding

The NEMA design letter​ (A-F) refers to the​ motor's _____.

starting torque characteristics

The name of the stationary motor part that produces the magnetic field during operation is the​ _____.

stator

The speed on a​ multiple-winding motor is normally changed by​ _____.

switching contacts in the motor controller

The two classes of AC motors are​ _____.

synchronous and induction

Counter- electromotive force opposes

the applied voltage

The minimum starting voltage is the​ _____.

the minimum voltage at which the motor will start without drawing excessive current

To protect the motor from overloads and starting​ failures, use a​ _____.

thermal protector

The angular difference between the rotor pole and the stator pole of an operating synchronous motor is called the​ _____ angle.

torque

A​ pipe-ventilated motor is classified as​ _____.

totally enclosed

A​ consequent-pole motor has​ _____.

two speeds

The​ shaded-pole motor is used in​ _____.

very low horsepower applications

An insulation resistance test can be used to determine​ _____.

whether a motor is damp

Which of these AC induction motor configurations would be selected for a​ variable-speed application?

wound rotor

According to the NEC Section 430.22​, when a single motor is supplied by a branch​ circuit, the ampacity must not be less than​ _____.

​​125% of the full load current

You would be unlikely to find a​ capacitor-start motor in a size larger than​ _____ horsepower.

10

motor controller must have a rating of no less than​ _____% of the motor full load current.

100

All motors must have a thermal protector if their voltage rating is greater than​ _____.

1000V

The rpm of a 60Hz motor with two poles is​ _____.

3600 rpm


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