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Motor Control 200 > Chapter 12 > Flashcards

Chapter 12 Flashcards

1
Q

One of the avantages of using a double-break contact instead of a single break contact is that a double-break contact _______.

A

has a higher contact rating in a smaller space.

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2
Q

________ power line(s) must be broken when using a contactor to control a 3 phase load.

A

three

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3
Q

_______ are uses to help confine, divide, and extinguish arcs for each set of contacts.

A

Arc chutes

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4
Q

The power rating of a contactor or motor starter_____as the NEMA number (size 1,2 etc..) of the contactor or motor starter increases.

A

increase

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5
Q

As ambient temperature increase, _____ current is needed to trip overload devices.

A

less

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6
Q

______ contactor assemblies are made of laminated steel.

A

AC

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7
Q

The current rating of a contactor or motor starter is the rating for ______.

A

each individual contact

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8
Q

Copper contact have been replace with _____ alloy contacts because of the problems of using copper with knife switches.

A

silver

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9
Q

A _____ diagram shows the connection and placement of an installation or its component devices or parts.

A

wiring

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10
Q

____________ interlock contactors are two contactors that are connected in such a way that both sets of contacts cannot be close at the same time

A

Mechanical

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11
Q

Manual starters are selected based on phasing, number of poles, voltage, starter size, and _________

A

enclosure type

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12
Q

A(n) _________ is a condition that occurs what a motor is loaded so heavily that cannot turn.

A

locked rotor

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13
Q

The three stages that a motor must go through in normal operation are resting, starting, and ___________.

A

operating under load

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14
Q

Fuses or________ are used to protect a motor against very high current, short circuit and, or a ground fault.

A

circuit breaker

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15
Q

A 120 V, 1 phase source has one hot wire and _______ natural wire(s)

A

one

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16
Q

A 230 V, 1 phase power source has two hot wires and _____ neutral wire(s)

A

no

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17
Q

A 3 phase power source has _____ hot wire(s) and zero neutral wires.

A

three

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18
Q

A _________ is a device that is used only periodically to remove electrical circuits from their supply source.

A

disconnect

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19
Q

Manual contactors are normally used with _____ circuit and resistance loads.

A

lighting

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20
Q

The main device in an overload relay is the _____.

A

eutectic alloy tube

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21
Q

A manual starter is a ___________ with an added overload protection divice.

A

contactor

22
Q

Overload protection devices are required by the _________.

A

NEC - National Electrical Code

23
Q

_________ temperature is the temperature of the air surrounding a motor.

A

Ambient

24
Q

A _______ alloy is a metal that has a fixed temperature at which it changes directly from a solid to a liquid state.

A

eutectic

25
Q

A starter may be reset after a _____ is removed.

A

overload

26
Q

Enclosures provide _______and electrical protection for the operator and the starter

A

mechanical

27
Q

An ___________is a control device that uses pushbuttons to energize the load connected to it.

A

manual contactor

28
Q

________ contact are contact that brake electrical circuit in two places

A

double-banker

29
Q

A(n) ____________ is a sensing device used to monitor the heat generated by excessive current and the heat created though ambient temperature rise.

A

heater coil

30
Q

NEMA Type ___________ enclosures are intendant for indoor use primarily to provide a degree of protection from human contact with the enclosed equipment in locations where unusual service condition do not exist.

A

one

31
Q

Manual motor starters are used in applications such as air compressors, conveyor systems, and _________.

A

drill presses

32
Q

Manual contactors directly control _________circuits.

A

power

33
Q

A(n) _____________ overload measures the strength of the the magnetic field around the wire instead of converting the current into heat.

A

electronic

34
Q

__________ arcs are the most difficult arcs to extinguish on a set of contacts.

A

DC

35
Q

The main difference between a contactor and a motor starter is the addition of ______ to the motor starter.

A

overload

36
Q

Two overload relays used to protect motors are thermal and _______ overload relays.

A

magnetic

37
Q

Ambient temperature, full-load current rating, and _________ must be know when selecting the overloads for a motor starter.

A

service factor

38
Q

An inherent motor protector is designed to protect a motor from _______

A

overloading

39
Q

__________ contactor assemblies may have several sets of contacts.

A

AC

40
Q

A(n)________ is a device that dissipates the energy present across opening contacts.

A

arc suppressor

41
Q

A(n) ___________ relay is an overload relay which resets automatically.

A

bimetallic

42
Q

A(n) ___________ is built into an overload device to indicate to the operator that an overload has taken place within the device.

A

trip indicators

43
Q

________ are used on large motor starter to reduce the current flowing to the overloads relay.

A

current transformer

44
Q

_________ are overload devices located directly on or in a motor to provide overload protection.

A

Inherent motor protector

45
Q

A(n) ____________ performs the same function as a motor starter, but can also vary motor speed, reverse the motor, and display operating information.

A

motor drive

46
Q

A(n) ________ is an electronic device that changes AC into DC

A

converter

47
Q

A(n) ________ is an electronic device that changes DC into AC

A

inverter

48
Q

Article _________ of the NEC covers the design and installation of electronic system that contain motors, motor circuits,and motor controllers.

A

430

49
Q

When motor was first introduced, they were started and stop by______.

A

knife switches

50
Q

______ are used to provide a magnetic field that helps move contacts apart as quickly as possible.

A

Blow-out coils

Motor Control 200 (10 decks)

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