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MK1 EOCT AUXILIARY EQUIPMENT > AC Motors and Switches > Flashcards

AC Motors and Switches Flashcards

1
Q

The two types of AC motors include the _______.

A

Induction Motor and Synchronous Motor

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2
Q

AC _____ motors , are probably the most widely used motor of the day.

A

AC Induction Motors

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3
Q

AC Induction Motors are either ________or________ induction design.

A

Squirrel Cage or Wound- Rotor

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4
Q

Synchronous AC motor types include:

A
  • Permanent Magnet
  • Field Wound
  • Stepper
  • Reluctance
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5
Q

Like most motors, an ______ has a fixed outer portion, (called the stator) and a rotor that spins inside with a carefully engineered air gap between the two

A

AC Induction Motor

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6
Q

_________ states that the direction of an induced current is always such that the changes causing induction are opposed.

A

Lenz’s Law

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7
Q

The ______ is made up of several thin laminations of aluminum or cast iron. They are punched and clamped together to form a hollow cylinder(stator core) with slots.

A

Stator

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8
Q

The number of poles of an AC induction motor depends on the internal connection of the ________.

A

Stator Windings

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9
Q

The _______ are connected directly to the power source.

A

Stator Windings

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10
Q

The _____ is made up of several thin steal laminations with evenly spaced bars, which are made up of aluminum or copper, along the periphery.

A

Rotor

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11
Q

What is the most popular type of rotor?

A

Squirrel Cage Rotor

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12
Q

Almost ____ percent of induction motor have squirrel cage motors.

A

90%

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13
Q

As the name suggest, the single-phase AC induction motor has:

A
  • Only one stator winding
  • Operates with a single phase power supply
  • The rotor is a squirrel cage type
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14
Q

The ______ is not self starting.

A

Single-phase induction AC motor

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15
Q

The _______ is required to have a starting mechanism that provide the starting “boost” for the motor to rotate.

A

Single-phase induction motor

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16
Q

What are the 5 classifications of the single-phase AC induction motor?

A
  • Split-Phase AC Induction Motor
  • Capacitor Start AC Induction Motor
  • Permanent Split Capacitor AC Induction Motor
  • Capacitor Start/Capacitor Run AC induction Motor
  • Shaded-Pole AC Induction Motor
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17
Q

The ____ is also known as the induction start/induction run motor.

A

Split-Phase Motor

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18
Q

________ has two windings, a start winding and main winding.

A

Split-Phase AC Induction Motor

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19
Q

The single phase induction motor start winding can have a series _________switch.

A

series capacitor and/or a centrifugal switch

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20
Q

The starting torque of a split-phase induction motor is low, typically _______of the rated torque.

A

100% to 175%

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21
Q

The split phase induction motor draws high starting current, approximately ________ of the rated current.

A

700% to 1000%

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22
Q

The maximum generated torque of the split phase motor ranges from ______ of the rated torque.

A

250% to 350%

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23
Q

All single phase motors are generally used for applications up to ____ hp only.

A

3/4 hp

24
Q

Good applications for split phase motors include:

A
  • small grinders
  • small fans
  • small blowers
  • and other low starting torque applications with power needs from 1/20 to 1/3 hp
25
Q

The ________ is a modified split-phase motor with a capacitor in series with the start winding to provide a start “boost”.

A

Capacitor Start AC Induction Motor

26
Q

Like the ______, the capacitor start motor also has a centrifugal switch which disconnects the start winding and the capacitor when the motor reaches about 75% of the rated speed.

A

split-phase motor

27
Q

Since the capacitor motor is in series with the start circuit, it creates more starting torque, typically _______ of the rated load.

A

200% to 400%

28
Q

The capacitor start motor is used in a wide range of belt drive applications like:

A
  • Small conveyors
  • large blowers
  • pumps
  • many direct drive or gear drive applications
29
Q

A _________has a run type capacitor permanently connected in series with the start winding.

A

Permanent Split Capacitor Motor

30
Q

What single phase motor is considered to be the most reliable?

A

Permanent Split Capacitor AC Induction Motor

31
Q

A _______ has a start type capacitor in series with the auxiliary winding the capacitor start motor for high-starting torque.

A

Capacitor Start/Capacitor Run AC Induction Motor

32
Q

This _____ allows high overload torque.

A

Run Type Capacitor

33
Q

_______ is able to handle applications too demanding for any other kind of single phase motor.

A

Capacitor Start/Capacitor Run AC Induction Motor

34
Q

Capacitor Start/Capacitor Run AC Induction Motor is used in high torque applications requiring 1 to 10 hp like:

A
  • woodworking machinery
  • air compressors
  • vacuum pumps
35
Q

________ only have one main winding and no start winding.

A

Shaded-Pole AC Induction Motor

36
Q

Because the Shaded-Pole AC Induction Motor lacks a start winding, starting switch and capacitor, it is ______ and ______.

A

Electrically simple and inexpensive

37
Q

What AC induction motor is usually considered “disposable” motors meaning they are cheaper to replace than repair?

A

Shaded-Pole AC Induction Motor

38
Q

Worldwide, various standards exist which specify various operating and constructional parameters of a motor. The two most wide used are?

A
  • National Electrical Manufacturers Association (NEMA)
  • International Electrotechnical Commission (IEC)
39
Q

NEMA is primarily associated with motors used in _____.

A

North America

40
Q

The standards NEMA developed represent the general industry practices and are supported by the manufacturers of electrical equipment. These standards can be found in the _______.

A

NEMA Standard Publication No. MG1

41
Q

Name some examples of items that would be listed on a nameplate attached to an AC Induction Motor:

A
  • Type
  • Horsepower
  • Amps
  • RPM
  • Duty
  • Class Insulation
  • Nema Design A, B, C, or D
  • Frame
  • Service Factor
  • Volts
  • Hertz
  • Date
42
Q

See __________ for all electrical safety precautions.

A

NSTM, Chapter 300, Electrical Plant-General

43
Q

________ are the simplest and most often used switches.

A

Single Pole

44
Q

_________ are electromechanical devices that require physical contact between a target object and switch activator to make the contacts change state.

A

Limit Switches

45
Q

What are the two types of limit switches?

A

Momentary and Spring Return

46
Q

________ return to their normal state as soon as the actuator passes it release point.

A

Momentary and Spring Return Switches

47
Q

__________ are actuated by change in pressure of a liquid or gas.

A

Pressure Switches

48
Q

Choices for for pressure switches measurement ranges include:

A
  • Absolute
  • Gauge
  • Vacuum
  • Differential
  • Sealed
49
Q

_________ switches are used where pressure are to be measured independently of natural fluctuations in the atmospheric pressure.

A

Absolutes switches

50
Q

______ are used to measure pressure above atmospheric pressure.

A

Gauges

51
Q

________measure vacuum pressure (negative pressure).

A

Vacumm Measurement Switches

52
Q

________ switches give the relative pressure between two points.

A

Differential Pressure Switches

53
Q

_______ gauge pressure measurement is similar in concept to an absolute pressure switch, except that the pressure of the media to be measured is compared to standard atmospheric pressure at sea-level.

A

Sealed gauge pressure measurement

54
Q

The ______ (rarely used) is the type that most easily demonstrates the functioning of a switch.

A

Knife Switch

55
Q

Today, used of knife switches has been confined to:

A
  • heavy duty industrial applications
  • demonstration purposes - science projects for example
56
Q

When replacing switches, it is very important to to ensure you wire the new one _______.

A

back in the same way the old one came out

MK1 EOCT AUXILIARY EQUIPMENT (8 decks)

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