Motor Control II

Question 1

A ____ is a three terminal, four layer semiconductor, alternating P and N type materials.

Answer 1

Silicon Controlled Rectifier (SCR)

Question 2

The interior barrier voltage for a silicon diode is approximately _________ volt(s).

Answer 2

0.6V

Question 3

A PN Junction in Forward bias has _____ resistance and Reverse bias has _____ resistance?

Answer 3

Low / High

Question 4

A region in a semiconductor in which there is neither an excess of electrons nor holes is known as ________ region?

Answer 4

Depletion

Question 5

The three terminals of the JFET are ___, ___, and ___?

Answer 5

Drain / Source / Gate

Question 6

The three terminals of the BJT are ___, ___, and ___?

Answer 6

Collector / Emitter / Base

Question 7

The addition of impurity atoms into the structure of a semiconductor is known as __________?

Answer 7

Doping

Question 8

A PN junction that operates like a small signal diode in forward direction, but is designed to operate in reverse?

Answer 8

Zener Diode

Question 9

Which semiconductor does current flow during both halves of the AC Cycle?

Answer 9

Triac

Question 10

A ____ is a device formed of either two P type materials and one N type, or Two N type and one P Type.

Answer 10

Bi-Polar Junction Transistor (BJT)

Question 11

A diode produces light is a _____?

Answer 11

Light Emitting Diode (LED)

Question 12

What is a 3 terminal device where the current flows through 2 terminals and is controlled by the 3rd with voltage?

Answer 12

Field Effect Transistor (FET)

Question 13

What is a 3 terminal device where the current flows through 2 terminals and is controlled by the 3rd with Current?

Answer 13

Bi-Polar Junction Transistor (BJT)

Question 14

The process of passing an AC voltage through a diode results in a _____ DC voltage?

Answer 14

Pulsating

Question 15

A diode that is switched on and off by light is a ____?

Answer 15

Photodiode

Question 16

_____ is used to transfer a signal between two electrically isolated circuits.

Answer 16

Optocoupler

Question 17

What detects the presence of an object when it comes within a specific distance of the sensor’s electrostatic field generated by a capacitor at the end?

Answer 17

Capacitive Proximity Sensor

Question 18

SSR Switching method ______ turns the load on when the sine wave crosses the zero axis.

Answer 18

Zero Switching

Question 19

What is a scanning method where the receiver and transmitter are housed in the same enclosure, and the transmitted beam is reflected back to the receiver off a polarized reflector?

Answer 19

Polarized Scan

Question 20

A ______ is a configurable solid state device with relay inputs and outputs. Similar to a PLC, but without the need for expensive software, and limited uses, and functions.

Answer 20

Programmable Logic Relay

Question 21

What is a scanning method where the receiver and transmitter are housed in the same enclosure, and the transmitted beam is reflected back to the receiver off the target?

Answer 21

Diffuse Scan

Question 22

Solid state devices have moving parts. T/F?

Answer 22

False

Question 23

SSR Switching method ______ turns the load on when the load voltage is at Peak.

Answer 23

Peak Switching Method

Question 24

What device is used to limit current extremely fast (about 2 msec)

Answer 24

Semiconductor Fuses

Question 25

What is a scanning method where the receiver and transmitter are housed in the same enclosure, and the transmitted beam is reflected back to the receiver off a reflector?

Answer 25

Retroflective Scan

Question 26

Solid State Relay’s A1 and A2 are called ______ rather than the “Coil”, which is used in electromechanical relays.

Answer 26

Inputs

Question 27

SSR Switching method ______ turns the load on immediately after control voltage is present.

Answer 27

Instant On

Question 28

What protects Solid State devices from Voltage Spikes by shunting current.

Answer 28

Metal-Oxide Varistor’s (MOV)

Question 29

What detects the presence of an object using emitting a high frequency sound signal and detecting its reflection back to the sensor?

Answer 29

Ultrasonic Proximity Sensor

Question 30

What is a scanning method with a transmitter and receiver opposite each other?

Answer 30

Direct Scan

Question 31

What is the technique used to link SSR inputs and outputs?

Answer 31

Optoisolation

Question 32

What detects the presence of an object when it comes within a specific distance of the sensor’s high frequency electromagnetic field?

Answer 32

Inductive Proximity Sensor

Question 33

When installing, operating, or maintaining an MCC, an electrical worker should use_______

Answer 33

Manufacturer's Manual

Question 34

A Drawout unit of an MCC is typically referred to as a _____.

Answer 34

Bucket

Question 35

The fault current is determined by the ______rated device withing the MCC

Answer 35

Lowest

Question 36

Coating the copper bus in an MCC with ___ protects it from corrosion.

Answer 36

Tin

Question 37

Inspect all cables for tight connections is a part of the Semi-Annual Maintenance of an MCC. T/F

Answer 37

False (It is part of the Annual Maintenance)

Question 38

Performing a Meggohm Meter test of all Motors is a part of the Annual Maintenance of an MCC. T/F

Answer 38

False

Question 39

______starters apply a low voltage to the motor at startup, and when the motor is at its running speed, a higher voltage is applied.

Answer 39

Reduced Voltage

Question 40

Reduced voltage starting for DC motors can be accomplished by _____ or solid state starter.

Answer 40

Rheostat

Question 41

Large current fluctiations result in ____, poor voltage regulation and harmonic issues on power systems.

Answer 41

Voltage Drops

Question 42

Solid state starters use ____ to control the voltage and current to the motor.

Answer 42

SCR's

Question 43

____ are used to offer greater control of the starting and stopping of motors.

Answer 43

Soft Starters

Question 44

The most common timing functions are On-Delay, Off-Delay, ______, and Repeat Cycle.

Answer 44

One-Shot

Question 45

The Off-Delay timer is activated by the use of _____ signal.

Answer 45

Trigger

Question 46

What timer uses equal on/off time periods?

Answer 46

Symmetrical

Question 47

What timer uses unequal on/off time periods (each are selectable)?

Answer 47

Asymmetrical

Question 48

A _____ timer maintains its current accumulated time value after power is removed, while _____ does not.

Answer 48

Retentive / Non-retentive

Question 49

Mechanical Latching relays are made with two types of coils, _____ and _____.

Answer 49

Latch / Unlatch

Question 50

Phase Sequence Relays monitor three-phase input for lost phase, or too high or low _____ level.

Answer 50

Voltage

Question 51

Frequency Relays monitor three phase voltage for change of frequency T/F?

Answer 51

False (single phase)

Question 52

The most commonly used Voltage Sensors are Overvoltage, Undervoltage and _____ relays.

Answer 52

Voltage Band

Question 53

When the resistance is removed from a Wound Rotor the rotor windings are shorted together, and the motor is at full speed.

Answer 53

True

Question 54

What controls the power to the motor by changing the firing angle of the AC sine wave?

Answer 54

Thyristor (SCR)

Question 55

What braking method injects DC current into two of the three windings of the motor?

Answer 55

Injection

Question 56

What braking method injects motor flux into all three phases?

Answer 56

Flux

Question 57

What braking method sends excess energy to an external resistor?

Answer 57

Dynamic

Question 58

What braking method sends excess energy back to the AC supply?

Answer 58

Regenerative

Question 59

When troubleshooting a VFD the phase to phase voltage should be within ____ of the specified level.

Answer 59

2%

Question 60

When troubleshooting a VFD the phase to phase FLC should be within ____ of the nameplate value.

Answer 60

10%