Motor Control II Flashcards
A ____ is a three terminal, four layer semiconductor, alternating P and N type materials.
Silicon Controlled Rectifier (SCR)
The interior barrier voltage for a silicon diode is approximately _________ volt(s).
0.6V
A PN Junction in Forward bias has _____ resistance and Reverse bias has _____ resistance?
Low / High
A region in a semiconductor in which there is neither an excess of electrons nor holes is known as ________ region?
Depletion
The three terminals of the JFET are ___, ___, and ___?
Drain / Source / Gate
The three terminals of the BJT are ___, ___, and ___?
Collector / Emitter / Base
The addition of impurity atoms into the structure of a semiconductor is known as __________?
Doping
A PN junction that operates like a small signal diode in forward direction, but is designed to operate in reverse?
Zener Diode
Which semiconductor does current flow during both halves of the AC Cycle?
Triac
A ____ is a device formed of either two P type materials and one N type, or Two N type and one P Type.
Bi-Polar Junction Transistor (BJT)
A diode produces light is a _____?
Light Emitting Diode (LED)
What is a 3 terminal device where the current flows through 2 terminals and is controlled by the 3rd with voltage?
Field Effect Transistor (FET)
What is a 3 terminal device where the current flows through 2 terminals and is controlled by the 3rd with Current?
Bi-Polar Junction Transistor (BJT)
The process of passing an AC voltage through a diode results in a _____ DC voltage?
Pulsating
A diode that is switched on and off by light is a ____?
Photodiode
_____ is used to transfer a signal between two electrically isolated circuits.
Optocoupler
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?
Capacitive Proximity Sensor
SSR Switching method ______ turns the load on when the sine wave crosses the zero axis.
Zero Switching
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?
Polarized Scan
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.
Programmable Logic Relay
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?
Diffuse Scan
Solid state devices have moving parts. T/F?
False
SSR Switching method ______ turns the load on when the load voltage is at Peak.
Peak Switching Method
What device is used to limit current extremely fast (about 2 msec)
Semiconductor Fuses
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?
Retroflective Scan
Solid State Relay’s A1 and A2 are called ______ rather than the “Coil”, which is used in electromechanical relays.
Inputs
SSR Switching method ______ turns the load on immediately after control voltage is present.
Instant On
What protects Solid State devices from Voltage Spikes by shunting current.
Metal-Oxide Varistor’s (MOV)
What detects the presence of an object using emitting a high frequency sound signal and detecting its reflection back to the sensor?
Ultrasonic Proximity Sensor
What is a scanning method with a transmitter and receiver opposite each other?
Direct Scan
What is the technique used to link SSR inputs and outputs?
Optoisolation
What detects the presence of an object when it comes within a specific distance of the sensor’s high frequency electromagnetic field?
Inductive Proximity Sensor
When installing, operating, or maintaining an MCC, an electrical worker should use_______
Manufacturer’s Manual
A Drawout unit of an MCC is typically referred to as a _____.
Bucket
The fault current is determined by the ______rated device withing the MCC
Lowest
Coating the copper bus in an MCC with ___ protects it from corrosion.
Tin
Inspect all cables for tight connections is a part of the Semi-Annual Maintenance of an MCC. T/F
False (It is part of the Annual Maintenance)
Performing a Meggohm Meter test of all Motors is a part of the Annual Maintenance of an MCC. T/F
False
______starters apply a low voltage to the motor at startup, and when the motor is at its running speed, a higher voltage is applied.
Reduced Voltage
Reduced voltage starting for DC motors can be accomplished by _____ or solid state starter.
Rheostat
Large current fluctiations result in ____, poor voltage regulation and harmonic issues on power systems.
Voltage Drops
Solid state starters use ____ to control the voltage and current to the motor.
SCR’s
____ are used to offer greater control of the starting and stopping of motors.
Soft Starters
The most common timing functions are On-Delay, Off-Delay, ______, and Repeat Cycle.
One-Shot
The Off-Delay timer is activated by the use of _____ signal.
Trigger
What timer uses equal on/off time periods?
Symmetrical
What timer uses unequal on/off time periods (each are selectable)?
Asymmetrical
A _____ timer maintains its current accumulated time value after power is removed, while _____ does not.
Retentive / Non-retentive
Mechanical Latching relays are made with two types of coils, _____ and _____.
Latch / Unlatch
Phase Sequence Relays monitor three-phase input for lost phase, or too high or low _____ level.
Voltage
Frequency Relays monitor three phase voltage for change of frequency T/F?
False (single phase)
The most commonly used Voltage Sensors are Overvoltage, Undervoltage and _____ relays.
Voltage Band
When the resistance is removed from a Wound Rotor the rotor windings are shorted together, and the motor is at full speed.
True
What controls the power to the motor by changing the firing angle of the AC sine wave?
Thyristor (SCR)
What braking method injects DC current into two of the three windings of the motor?
Injection
What braking method injects motor flux into all three phases?
Flux
What braking method sends excess energy to an external resistor?
Dynamic
What braking method sends excess energy back to the AC supply?
Regenerative
When troubleshooting a VFD the phase to phase voltage should be within ____ of the specified level.
2%
When troubleshooting a VFD the phase to phase FLC should be within ____ of the nameplate value.
10%
