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All handouts Flashcards

1
Q 
When using in an industrial sensing application, a heated metal will
A: contract 
B: expand 
C: melt 
D: none of the above
A

B: expand

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2
Q 
Two dissimilar metals bonded together have
A: a high expansion rate 
B: a low expansion rate 
C: different expansion rate 
D: none of the above
A

C: different expansion rate

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3
Q 
If electrical contacts are permitted to open and close slowly 
A: poor contact pressure will result 
B: contacts burn-out can occur 
C: a and b 
D: neither a or b
A

C: a and b

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4
Q 
A metal that remains in a liquid stage at room temperature is 
A: Copper 
B: brass 
C: tin 
D: mercury
A

D: mercury

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5
Q 
A RTD is made of 
A: Copper wire 
B: platinum wire 
C: chrome wire 
D: iron wire
A

B: platinum wire

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6
Q 
A bellows type thermostat works on a change in 
A: heat principals 
B: movement principles 
C: resistance principles 
D: pressure principles
A

D: pressure principles

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7
Q 
A device that heats two dissimilar  metals to produce a voltage is known as a
A: thermostat 
B: thermometer 
C: thermoreactor
D: thermocouple
A

D: thermocouple

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8
Q 
Two or more thermocouples connected in series are known as a 
A: thermopile 
B: thermostat
C: a and b 
D: neither a or b
A

A: thermopile

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9
Q 
A device that works on the principles of a change in resistance with a change in heat is known as a 
A: resistance temperature detector 
B: thermocouple 
C: thermometer 
D: thermopile
A

A: resistance temperature detector

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10
Q 
Thermistors exhibit a \_\_\_\_\_\_\_\_\_\_ change of resistance at a certain temperature 
A: rapid 
B: linear 
C: gradual
D: a and b
A

A: rapid

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11
Q 
A hall generator is constructed as a 
A: coiled device 
B: vacuum device 
C: capacitive device 
D: integrated device
A

D: integrated device

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12
Q 
Materials used to shunt a magnetic field away from objects is known as a 
A: detector
B: reactor 
C: pulser 
D: reluctor
A

D: reluctor

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13
Q 
Proximity detectors are basically 
A: light detector 
B: heat detector 
C: metal detector 
D: all of the above
A

C: metal detectors

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14
Q 
Proximity detectors will more easily detect \_\_\_\_\_\_\_ because it is ferrous 
A: copper 
B: iron
C: brass
D: aluminum
A

B: iron

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15
Q 
A hall sensor is used to sense the presence of 
A: an electrical field 
B: heat 
C: a magnetic field 
D: none of the above
A

C: a magnetic field

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16
Q 
If a disk with magnetic poles around its circumference is attracted to a rotating shaft, and a hall sensor is mounted near the disk, the hall sensor 
A: will sense the poles as they pass by
B: can be used to sense the present 
C: can be used as a tachometer 
D: all of the above
A

D: all of the above

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17
Q

With proximity detectors, sensors should be mounted as
A: far away from each other as possible
B: close to each other as possible
C: close to ferrous materials as possible
D: all of the above

A

A: far away from each other as possible

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18
Q 
A proximity detector that detects non-metallic objects operate in a change in 
A: resistance 
B: capacitance 
C: inductance 
D: impedance
A

B: capacitance

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19
Q 
Most capacitive proximity detectors can sense the presence of 
A: wood 
B: copper 
C: brass 
D: all of the above
A

D: all of the above

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20
Q 
Most capacitive proximity detectors have a range of approximately 
A: 5mm
B: 10mm
C: 25mm 
D: 100mm
A

C: 25mm

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21
Q 
Ultrasonic detectors have a wide range of adjustable 
A: frequency 
B: sensing speed 
C: sensing distance 
D: physical size
A

C: sensing distance

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22
Q 
Ultrasonic detectors emit a 
A: low frequency sound 
B: high frequency sound 
C: low frequency radio wave 
D: high frequency radio wave
A

B: high frequency sound

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23
Q 
Photodetector detect
A: sound 
B: mechanical motion 
C: light 
D: heat
A

C: light

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24
Q 
Compared to most other photodetector, a photoemissive device are a 
A: more reliable device 
B: slower device 
C: smaller in size 
D: faster device
A

D: faster device

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25
Q 
When exposed to light, a photoconductive device change 
A: voltage 
B: resistance 
C: the direction of current flow 
D: the polarity of voltage applied
A

B: resistance

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26
Q 
Photo detectors with both transmitter and receiver mounted in one housing need 
A: refractor to operate 
B: LED to operate 
C: a cad cell to operate 
D: reflector to operate
A

D: reflector to operate

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27
Q 
Photo detectors can be used to sense the presence or absence of 
A: almost any object 
B: light absorbing object 
C: objects with holes in them 
D: none of the above
A

A: almost any object

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28
Q 
Sensors and detectors can be used in a manner similar to a 
A: limit switch 
B: pressure switch 
C: float switch 
D: any digital device
A

D: any digital device

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29
Q 
Squirrel cage induction motos are characterized by
A: simplicity 
B: ruggedness 
C: reliability 
D: all of the above
A

D: all of the above

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30
Q 
An excellent choice for alternating current, all purpose, constant speed motor applications would be a 
A: dc motor 
B: squirrel cage motor 
C: stepping motor 
D: none of the above
A

B: squirrel cage motor

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31
Q 
The part of a squirrel cage motor that remains stationary is called the 
A: shaft
B: armature 
C: rotor 
D: stator
A

D: stator

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32
Q 
The part of the squirrel cage motor that rotates is called the 
A: armature 
B: rotor 
C: stator 
D: none of the above
A

B: rotor

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33
Q 
The stator for a squirrel cage motor never has fewer than 
A: 2 poles 
B: 4 poles 
C: 6 poles 
D: 8 poles
A

A: 2 poles

34
Q 
A squirrel cage motor with one pare of poles, powered by a 50hz ax source will run at 
A: 50r/min
B: 60r/min
C: 3000r/min
D: 3600r/min
A

C: 3000 r/min

35
Q 
A squirrel cage motor with 6 poles, powered by a 60hz ac source will run at 
A: 600r/min
B: 1200r/min
C: 1800r/min
D: 3600r/min
A

B: 1200r/min

36
Q 
In a squirrel cage motor, the current induced has its largest value when the motor 
A: is at standstill
B: is just starting 
C: has reached its highest torque 
D: has reached its highest speed
A

B: is just starting

37
Q

With regard to a squirrel cage motor, the current
A: remains constant as motor speed increases
B: increases sharply as the motor approaches its full rated speed
C: drops sharply as the motor approaches it’s full rated speed
D: remains constant as the motor speed decreases

A

C: drops sharply as the motor approaches it’s full rated speed

38
Q 
When a squirrel cage motor is connected directly to the plant distribution
A: manual started may be used
B: a magnetic starter may be used 
C: a and b
D: neither a or b
A

C: a and b

39
Q

With regard to a squirrel cage motor, when the voltage is reduced to start the motor, the
A: current is increased, but the machines torque is reduced
B: current is also reduced , but the machines torque increases
C: current is increased and so is the machines torque
D: current is also reduced, and so is the machines torque

A

D: current is also reduced, and so is the machines torque

40
Q 
Split phase motor often use \_\_\_\_\_\_\_\_\_\_\_ to disconnect the starting windings from the power line 
A: centrifugal switch 
B: capacitive switch 
C: an inductive switch 
D: non of the above
A

A: a centrifugal switch

41
Q 
\_\_\_\_\_\_\_\_\_\_ starting is the simplest of all starting methods 
A: across the line 
B: autotransformers 
C: wye-delta 
D: part windings
A

A: across the line

42
Q 
The starting windings of single phase motors is disconnected when the motor reaches at about \_\_\_\_\_\_\_\_\_\_ precent of its rates speed 
A: 45
B: 55
C: 65
D: 75
A

D: 75

43
Q 
The most popular motor used in North American industry is 
A: the synchronous motor 
B: the servo motor 
C: three phase squirrels cage motor 
D: the wound rotor motor
A

C: three phase squirrel cage motor

44
Q 
The initial in rush current of a motor is comparable to 
A: the fla 
B: locked rotor current
C: no load amps 
D: all of the above
A

B: locked rotor current

45
Q 
Plugging controls provide for the 
A: rapid stop of motor rotation 
B: quick reversal of motor rotation
C: a and b
D: neither a or b
A

C: a and b

46
Q 
Another term for plugging switch
A: start/stop/reversal switch
B: on/halt/reverse switch
C: push/pull switch 
D: zero speed switch
A

D: zero speed switch

47
Q 
Plugging switches are designed to be added to control circuits as 
A: feeder devices 
B: actuators 
C: pilot device 
D: contact devices
A

C: pilot device

48
Q 
Most machines in which plugging is done are driven by
A: linear motor 
B: squirrel cage motors 
C: ac motors 
D: dc motors
A

B: squirrel cage motors

49
Q

The shaft of a plugging switch is most often connected
A: electrically to the motor shaft on the machine it controls
B: electronically to motor shaft on the machine it controls
C: mechanically to the shaft on the machine it controls
D: pneumatically to the shaft on the machine it controls

A

C: mechanically to the shaft on the machine it controls

50
Q 
The rotating motion of a motor is transmitted to plugging switch contacts either by a magnetic or by
A: centrifugal mechanism 
B: capacitive reactance 
C: inductive reactance 
D: thermal reactance
A

A: centrifugal mechanism

51
Q 
A plugging switch acts as a link between a motor and a 
A: reversing starter 
B: normally close stop button 
C: normally open stop button
D: overload switch
A

A: reversing starter

52
Q 
In a plugging device, to operate the torque and insure that the contacts open and close at the proper time regardless of motor speed, a 
A: clutch plate is used 
B: set screw is used 
C: adjustable contact spring is used 
D: rotating cup is used
A

C: adjustable contact spring is used

53
Q 
A plugging switch must be driven by a 
A: negative means 
B: open means 
C: closed means 
D: positive means
A

D: positive means

54
Q 
Which is not a preferred method of driving a plugging switch 
A: gearing 
B: chain driven 
C: direct flexible coupling 
D: belt driven
A

D: belt driven

55
Q 
In determining the direction of motor rotation, the electrician will connect motor leads at the 
A: source 
B: transformer 
C: control switch bank 
D: motor
A

D: motor

56
Q 
To protect people, machines, and production processes a 
A: lockout relay is used 
B: latching relay is used 
C: Time delay relay is used 
D: lockable disconnect switch is used
A

A: lockout relay is used

57
Q

A starter used for a plugging switch will
A: interchange two leads for a 3 phase motor
B: reverse of the armature for a dc motor
C: reverse the windings for a 1-PH motor
D: all of the above

A

D: all of the above

58
Q 
When a device prevents the application of a counter torque until the motor speed is reduced to an acceptable value it is known as
A:anti plugging 
B: plugging 
C: locking out 
D: compensating
A

A: anti plugging

59
Q 
The most accurate method of plug stopping a motor is a 
A: one speed switch 
B: rotating switch 
C: zero speed switch
D: resistor
A

C: zero speed switch

60
Q 
Three main methods of breaking a motor are 
A: coasting, mechanical, dynamic 
B: mechanical, coasting, plugging 
C: mechanical, dynamic, plugging 
D: coasting, dynamic, plugging
A

C: mechanical, dynamic, plugging

61
Q

What are the two basic classifications of timers?

A

Mode A and mode D

62
Q

Name two methods used by electronic timers to obtain their time base.

A

RC timer constant and quartz clocks

63
Q 
With reactor or primary resistor type starter, reactor or resisters are 
A: connected in parallel with the motor 
B: connected in series with the motor 
C: connected in parallel with CR 
D: connected in series with a TR
A

B: connected in series with the motor

64
Q

In regards reactor or primary resistance starting; a start under load (as opposed to no load) will result in a
A: longer acceleration time to full speed and longer initial inrush current period
B: longer acceleration time to full speed and shorter initial inrush current period
C: shorter acceleration time to full speed and longer initial inrush current period
D: shorter acceleration time to full speed and shorter initial inrush current period

A

A: longer acceleration time to full speed and longer initial inrush current period

65
Q

It is desirable to limit the starting current of a motor if full voltage starting causes serious line disturbances on
A: lighting circuits
B: circuits supplying computers and other electronics
C: circuits supplying fire alarms, security system, etc
D: all of the above

A

D: all of the above

66
Q

Large current inrush during the starting of a large motors may cause
A: the control circuit to change
B: utility line disturbance and damage to machines due to over torque
C: excess motor speed
D: all of the above

A

B: utility line disturbance and damage to machines

67
Q

Closed transition starting means that the motor is
A: momentarily disconnected at the beginning of the starting cycle
B: momentarily disconnected at the end of the starting cycle
C: connected to the line only when full voltage is applied
D: never disconnected from the line from the moment it is first connected until the motor is operating at full voltage

A

D: never disconnected from the line from the moment it is first connected until the motor is operating at full voltage

68
Q 
There are conditions where it is not acceptable to start a motor across the line due to excessive 
A: starting current of torque 
B: size of equipment 
C: acceleration time 
D: cost of equipment
A

A: starting current to torque

69
Q 
The rate of a rise of current in a circuit is \_\_\_\_\_\_\_\_\_\_ circuit s
A: immediate in resistive 
B: always constant in AC
C: at an exponential curve in inductive 
D: both a and c
A

D: both a and c

70
Q 
If the motor is disconnected from the line between the start and run stage, the starting method is referred to as 
A: a transition type 
B: an open transition 
C: a closed transition 
D:a corrupt transition
A

B: an open transition

71
Q 
Most motors are successfully started at 
A: 25% 
B: 50%
C: 65%
D: 80%
A

C: 65%

72
Q 
Both primary resistor ans reactor starters are available for use on
A: single phase reversing operations 
B: three phase reversing operations 
C: a and b 
D: neither a or b
A

C: a and b

73
Q 
Some circuits may use several steps of starting because of 
A: limitation by the utility 
B: torque limits of a machine 
C: length of acceleration time desired 
D: all of the above
A

D: all of the above

74
Q 
Starting transistors are considered 
A: resistive loads 
B: inductive loads 
C: capacitive loads 
D: all the above
A

B: inductive loads

75
Q 
Autotransformers used as a reduced starter must have a minimum of 
A: two taps 
B: three taps 
C: four taps 
D: six taps
A

A: two taps

76
Q 
Autotransformers starters are generally employed to start \_\_\_\_\_\_\_ type motors 
A: synchronous 
B: squirrel cage 
C: non induction 
D: wound rotor
A

B: squirrel cage

77
Q

Motors started with autotransformers reduced voltage starters draw
A: less current and develops less torque than when connected to line voltage
B: less current and develop more torque than when connected to line voltage
C: more current and develop more torque than when connected to line voltage
D: more current and develop less torque than when connected to line voltage

A

A: less current and develops less torque than when connected to line voltage

78
Q 
\_\_\_\_\_\_\_\_\_\_\_\_\_ are often used to sense the current of large motors 
A: current resistors (CR’s)
B: current varistors (CV’s)
C: current capacitor (CC’s)
D: current transformers (CT’s)
A

D: current transformers (CT’s)

79
Q 
Some resistors and reactors starters use multiple steps of starting. This is accomplished by tapping the resistor or reactor to provide different values 
A: resistance or capacitance 
B: frequency or resistance 
C: resistance or inductive reactance 
D: capacitance or inductive reactance
A

C: resistance or inductive reactance

80
Q

When an auto transformer is used as a reduced voltage starter,
A: a fixed timer controls when the motor receives full voltage
B: an adjustable timer controls when the motor receives full voltage
C: a fixed counter controls when the motor receives full voltage
D: an adjustable counter when the motor receives full voltage

A

B: an adjustable timer controls when the motor receives full voltage

Control System (1 decks)

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