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Distributed Generation > Motors 3 > Flashcards

Motors 3 Flashcards

1
Q

The torque produced by a motor overload that pulls the rotor out of synchronization is referred to as ? torque.
Select one:

a.
pull-in

b.
pull-out

c.
reluctance

d.
synchronous

A

B

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2
Q

A ? may be used to start the rotor rotation and speed it up to almost synchronous speed.
Select one:

a.
motor-generator set

b.
permanent magnet

c.
pony motor

d.
static exciter

A

C

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3
Q

If a synchronous motor rotor slips out of synchronous speed for a period of time, ? are needed to shut it down.
Select one:

a.
commutators

b.
compressors

c.
discharge resistors

d.
protective relays

A

D

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4
Q

The current in the stator power circuit is at minimum level when a synchronous motor is at ? power factor.
Select one:

a.
lagging

b.
leading

c.
low

d.
unity

A

D

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5
Q

In an application of ? circuit logic, a motor must be allowed to decelerate by coasting or braking before being changed to a low speed.
Select one:

a.
accelerating

b.
compelling

c.
decelerating

d.
modified

A

C

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6
Q

A circuit with ? circuit logic allows the operator to select the desired speed by pressing either the low or high pushbutton.
Select one:

a.
accelerating

b.
circulating

c.
compelling

d.
dynamic

A

A

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7
Q

? circuit logic is used in applications where a motor or load cannot withstand the stress of changing quickly from high speed to low speed.
Select one:

a.
Accelerating

b.
Circulating

c.
Compelling

d.
Decelerating

A

D

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8
Q

The relative position of the ? in Schrage AC motors is altered to change the speed of the motor.
Select one:

a.
brushes

b.
rotor windings

c.
slip rings

d.
wye connections

A

A

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9
Q

A consequent-pole motor with two poles when wired in series has ? poles when wired in parallel.
Select one:

a.
1

b.
2

c.
4

d.
8

A

C

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10
Q

Damage may occur to an AC motor if the supply voltage is varied more than ? above or below the rated nameplate voltage.

Select one:

a.
3%

b.
5%

c.
10%

d.
15%

A

C

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11
Q

Torque decreases when the voltage is lower than the rated voltage. With 95% of rated voltage, the torque is ? of rated torque.
Select one:

a.
5%

b.
10%

c.
90%

d.
100%

A

C

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12
Q

The frequency of the voltage used to control motor speed is called the ? frequency.
Select one:

a.
alternative

b.
carrier

c.
fundamental

d.
static

A

C

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13
Q

The speed of standard AC squirrel-cage motors is normally varied by changing the number of poles or the ? .
Select one:

a.
applied frequency

b.
current

c.
drive rating

d.
series connection

A

A

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14
Q

? control is a method of controlling the voltage applied to the armature of a DC motor.
Select one:

a.
AC field-voltage

b.
DC field-current

c.
SCR armature-voltage

d.
Sensorless field-current

A

C

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15
Q

A ? bearing is a rolling-contact bearing that has cylindrical or tapered steel rollers confined between inner and outer rings.
Select one:

a.
ball

b.
Conrad

c.
friction

d.
roller

A

D

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16
Q

? roller bearings have a high radial load capacity but are not designed for axial loads and cannot tolerate misalignment.
Select one:

a.
Cylindrical

b.
Ball

c.
Spherical

d.
Tapered

A

A

17
Q

? bearings are used in areas of heavy loads where space is limited.
Select one:

a.
Ball

b.
Friction

c.
Needle

d.
Tapered

A

b

18
Q

A(n) ? clutch uses a magnetic field to couple a motor to a load.
Select one:

a.
coupling

b.
eddy-current

c.
friction

d.
magnetic

A

B

19
Q

A ? is a coupling that connects or disconnects the motor shaft to a drive shaft while the motor is running.
Select one:

a.
clutch

b.
flexible coupling

c.
gear

d.
rigid coupling

A

A

20
Q

? transmit torque to and from a pulley through the wedging action of the tapered sides of the belt in the pulley groove.
Select one:

a.
Chains

b.
Timing belts

c.
Timing chains

d.
V-belts

A

D

21
Q

? misalignment is the situation where two shafts are parallel but are not on the same axis.
Select one:

a.
Angular

b.
Nonparallel

c.
Offset

d.
Springing

A

C

22
Q

The ? alignment method uses two dial indicators to take readings of opposing sides of coupling rims, giving two sets of shaft runout readings.
Select one:

a.
coupling

b.
laser rim-and-face

c.
reverse dial

d.
rim-and-face

A

C

23
Q

A(n) ? occurs when current leaves its normal path and travels to the frame of the motor.
Select one:

a.
dead circuit

b.
ground fault circuit

c.
open circuit

d.
overload circuit

A

B

24
Q

? is the most common causes of motor failure.
Select one:

a.
Misalignment

b.
Overloading

c.
Rotor failure

d.
Single phasing

A

B

25
Q

? is a power supply problem that occurs when one of the 3-phase lines leading to a 3-phase motor no longer delivers voltage to the motor.
Select one:

a.
Phase unbalance

b.
Single phasing

c.
Voltage blocking

d.
Voltage surging

A

B

26
Q

A ? motor is an AC motor that uses induction to create linear movement.
Select one:

a.
compensated universal

b.
linear induction

c.
noncompensated universal

d.
stepper

A

B

27
Q

The main parts of a universal motor are the field windings and the ? .
Select one:

a.
armature

b.
pigtails

c.
reverse coils

d.
rotor

A

A

28
Q

? rely on electric commutation (pulses) to provide motion control.
Select one:

a.
Linear motors

b.
Servomotors

c.
Stepper motors

d.
Synchronous motors

A

C

29
Q

A motor is ? when it draws more than rated current.
Select one:

a.
overcycled

b.
overloaded

c.
overshaded

d.
unbalanced

A

B

30
Q

A(n) ? is a rigid steel support for firmly coupling and aligning two or more rotating devices.
Select one:

a.
anchor

b.
base plate

c.
dowel

d.
foundation

A

B

31
Q

? braking requires more maintenance than any other method of braking.
Select one:

a.
Electric

b.
Friction

c.
Magnetic

d.
Regenerative

A

B

32
Q

Plugging a motor to a stop results in high current and heat.
Select one:
True
False

A

True

33
Q

? braking can be used to provide an immediate stop, particularly in an emergency situation.
Select one:

a.
Electric

b.
Dynamic

c.
Interlock

d.
Magnetic

A

A

34
Q

Power resistors are used with ? braking to dissipate the heat of braking.
Select one:

a.
dynamic

b.
electric

c.
friction

d.
plugging

A

A

35
Q

The motor connections are reversed with ? so that the motor develops a reversed torque to brake the motor.
Select one:

a.
friction braking

b.
plugging

c.
reversing braking

d.
rigging

A

B

Distributed Generation (23 decks)

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