Motor Control 2 Flashcards
A diffuse scan device can not only tell when an object is near it, but can tell what else about the obstruction?
How far away it is from the sensor.
Semiconductor fuses are able to open the circuit in as fast as __ Ms
2Ms
Zener diodes are most commonly used for ____.
Voltage Regulation.
What is this symbol?
An LED
(Light Emitting Diode)
How does a Diac differ from a Triac?
It does not have a gate.
T/F; The resistance of the diode essentially changes when the width of the depletion region changes.
True.
T/F: Peak Inverse Voltage and Reverse Bias breakdown voltage are the same.
FALSE. Peak Inverse is the maximum amount of reverse bias voltage that the diode can handle BEFORE breakdown.
Electromechanical Relays VS SSR’s: Which withstands shock and vibration better?
SSR’s
What does ‘SSS’ stand for?
Solid State Starter.
What does SCR stand for?
Silicon Controlled Rectifier
To protect an SSR from voltage spikes, a ____ is added across the output terminals of the device.
MOV
What is this symbol?
NPN Transistor
Electromechanical Relays VS SSR’s: Which switches faster?
SSR’s
Electromechanical Relays VS SSR’s: Which has no moving parts?
SSR’s.
Electromechanical Relays VS SSR’s: Which is cheaper?
Electromachanical Relays
Semiconductor with a deficiency of electrons is called a ____ material.
P-type.
A device with a material type makeup of ‘PNP’ or ‘NPN’ would be called a ‘Bi-Polar Junction ____”
Transistor
Discrete sensors only two outputs are ____ or ____.
ON or OFF
Zener diodes hold the same ____ while ____ may vary.
Voltage, Current.
SCR’s have a count of ____ layers and ____ junctions.
4 Layers, 3 Junctions
In Solid State Starting, the voltage will initially be between __% and __% of line voltage.
15-50%
What are the three leads/terminals off of a PNP or NPN transistor?
Emitter, Collector, and Base.
The depletion region of a silicone diode creates an interior ____ voltage of about ____V.
Barrier, .6V
Diodes are commonly used to convert AC voltage to a ____ DC voltage.
Pulsing.
What does CT stand for?
Control Transformer
____ are used to protect SSR’s from any sort of overcurrent condition.
Semiconductor Fuses.
How is a Rheostat controlled?
Manually, by a human operator.
Why do we reduce the impact of motor starting?
Because it is hard on your system and components, will wreck or diminish the life of your equipment.
What types of objects can an Inductive proximity sensor detect?
Ferrous or Nonferrous Metals.
Optocouplers allow signals between what?
Isolated Circuits.
What does JFET stand for?
Junction Field Effect Transistor
The N side of a PN junction diode is called the ____.
Cathode
The process of converting AC voltage to DC voltage is called ____.
Rectification.
How does a Retroflective scan work?
Much like the Direct scan, except that the transmitter and collector are housed together with the beam shooting out, being reflected and coming back. It is triggered when the beam is obstructed.
What type of motor must be used for part winding starters?
A Dual-Voltage Motor.
When doping a semiconductor to get an “N-type” material, you would use a material that has ____ electrons in its valence shell.
5
MCC’s should be installed per ____.
The manufacturers recommendations
Electromechanical Relays VS SSR’s: Which has no arcing parts?
SSR’s
Electromechanical Relays VS SSR’s: Which is more common?
Electromechanical Relays
What is this symbol?
Normally Closed Proximity Switch (NEMA)
What does SSR stand for?
Solid State Relay
A ____ emits energy at wavelengths of the visible light spectrum or infrared when it is forward biased.
Light-emitting-Diode. (LED)
A ____ is an efficient way to localize and organize motor control equipment.
Motor Control Center (MCC)
Solid State Starters use ____ in parallel to basically create a soft start
SCR’s
Optocouplers are used to do what?
To provide a signal between two isolated circuits.
Is an NPN transistor Sinking or Sourcing?
Sinking
An SCR is much like a diode, except it has a ____ for switching purposes.
Gate.
Is a PNP transistor Sinking or Sourcing?
Sourcing
What is this symbol?
A Photodiode
The area between the N-type and P-type materials in a PN junction is called the ____.
Depletion Region
What is this symbol?
PNP Transistor
What setting on a multimeter would be used to test a diode?
The Ohmmeter or resistance setting.
What is this symbol?
Normally Open Proximity Sensor (NEMA)
Triacs and Diacs can do what differently than diodes?
They can conduct current in either direction, making them able to handle an AC sinewave.
When a BJT is operating as an amplifier, it is in the ____ region. When it is operating as a switch, it’s either in the ____ region or the ____ region.
Amplifier - Active Region Switch - Cutoff Region and Saturation Region
When Wye-Delta starters transition to delta in the second phase of startup, the full windings are connected, which make the line-line voltage correct for maximum ____.
Horsepower.
How are Part Winding starters used to start motors?
Half of the coils are connected at turn on, and then the rest are connected in parallel when the motor is at running speed.
How does a Direct scan detection system work?
The transmitter and collector are housed separately with a beam inbetween. It is triggered when the beam is obstructed.
When doping a semiconductor to get an “P-type” material, you would use a material that has ____ electrons in its valence shell.
3
Electromechanical Relays VS SSR’s: Which is easier to troubleshoot?
Electromechanical Relays
T/F: You can buy SSR’s programmable or not programmable.
True.
A ____ is a device that allows reverse current flow when light-energy is focused on its P-type semiconductor.
Photodiode
When your facility classifies as light-duty, MCC maintenance should be done ____.
Semi-annually.
When Wye-Delta starters begin in the wye configuration at turn on, the windings are in series which makes the ____ low.
Current.
What things is an Ultrasonic proximity sensor effective at detecting? What two things do they have trouble detecting?
Effective -> Smooth, Flat surfaces. Ineffective -> Round or Irregular
MCC’s are designed to be installed on a ____ surface.
Clean/Flat
Optocouplers have a glass ____ between the components of the two isolated circuits they contain.
Dielectric
What types of objects can a Capacitive proximity sensor detect?
Metals, glass, plastic, and liquids.
What does MCC stand for?
Motor Control Center
What are the three states or “Ranges” of a JFET?
1.) Active (Amplification) 2.) Cutoff (Acts like open switch) 3.) Saturation (Acts like closed switch)
A diode is forward biased when the cathode is connected to the ____ side of the source and the anode is connected to the ____ side of the source.
Negative, Positive.
What two types of reduced voltage starting are used for DC motors?
1.) Rheostat 2.) SSS (Solid State Starter)
What are the three leads on transistors labeled?
Base, Collector, and Emitter
What does “BJT” stand for?
Bi-Polar Junction Transistor
What does PLR stand for?
Programmable Logic Relay.
How does a polarized scan work?
Almost exactly like a Retroflective scan, except the the polarized light used is more resistant to being obstructed by dust/dirty air.
What is this symbol?
SCR
A ____ is a SSD that combines a photodiode and a transistor.
Phototransistor.
What are the four photoelectric scanning methods?
1.) Direct 2.) Retroflective 3.) Polarized Scan 4.) Diffuse
Adding impurities to a pure material is a process called ____.
Doping
What two things are BJT’s used for?
Amplification and Switching.
To conduct current, the semiconductor must be ____ biased.
Forward.
The P side of a PN junction diode is called the ____.
Anode
A diode that is designed to be used in reverse bias but only when it hits a certain voltage is called a ____ diode.
Zener.
Semiconductor with an excess of electrons is called an ____ material.
N-type.
____ starters use electronics to monitor and control voltage and current.
Solid State.
When a diode is reverse biased, the depletion region will ____.
Expand.
In forward bias, the positive side of the energy source is connected to the ____ and the negative side is connected to the ____.
Positive -> Anode Negative -> Cathode
What is this symbol?
Triac
What are the three types of proximity sensors?
1.) Inductive 2.) Capacitive 3.) Ultrasonic
Electromechanical Relays VS SSR’s: Which is more prone to create heat?
SSR’s
The more electrons in the valence ring of an atom, the more ____ the material is.
Stable.
MCC’s are usually __” wide, __” tall, and __” deep.
15” wide 90” tall 15-20” deep
The two most common semiconductor materials are ____ and ____.
Silicon and Germanium
What is this symbol?
Diode.
What is this symbol?
Diac
What does PT stand for?
Potential Transformer
While transistors are switched with a pulse of ____ to the base, JFET’s are switched with ____.
Transistors -> Current JFET -> Voltage
If and atom loses an electron, the place where that electron used to be is referred to as a ____.
Hole.
T/F; When the semiconductor is conducting current, the depletion region is expanded.
False.
SSR’s switch anywhere between __ and __ amps.
3-40A
Electromechanical Relays VS SSR’s: Which consumes more power?
Electromechanical Relays
What are the three leads/terminals coming off of a JFET?
1.) Drain 2.) Source 3.) Gate
A ____ has characteristics of both insulators and conductors.
Semiconductors
What does MOV stand for?
Metal-Oxide Varistor
When SSR’s get hot or are installed in a warmer ambient temperature, sometimes a ____ is needed to keep them cool.
Heat Sink.
A ____ is a semiconductor device that only allows current to flow in one direction.
Diode.
While a ____ is controlled by current, a ____ is controlled by voltage.
BJT (Bi-Polar Junction Transistor) FET (Field Effect Transistor)
The only way current will flow in reverse bias is if the ____ voltage is reached.
Breakdown.
The two types of Repeat-Cycle timers are ____ and ____.
Symmetrical and Non-Symmetrical
NOTO and NCTO timers are ___-delay timers.
Off.
NOTC and NCTC are ____ -delay timers.
On.
What are the three types of latching relays?
- ) Mechanical
- ) Impulse
- ) Magnetic.
For mechanical latching relays, there is usually two coils, the ____ and ____ coils.
Latching and Unlatching
PSR’s (Phase Sequence Relays) moniter ____ power for phase failures/issues.
three phase
____ relays moniter a single phase imput voltage for a change in frequency.
Frequency.
____ alternate loads for even wear and tear on equipment.
Pump Sequencers
____ sensors monitor voltage and protect against excessive voltage.
Voltage
In sequencing, the first load is called the ____ load and the second is called the ____ load.
Lead, Lagging
SCR’s and Dics/Triacs in single phase motor speed control changed the ____ of the AC sine wave to control speed.
Firing Angle.
____ are basically two SCR’s put together.
Triacs.
What are the four types of electric braking for electric motors?
- ) Injection
- ) Dynamic
- ) Flux
- ) Regenerative
____ braking is when the VFD redirects the extra energy through resistors to dissapate it.
Dynamic
When troubleshooting AC motor drives, Voltage should be within ____ % of the specified value.
2%
When troubleshooting AC motor drives, the current should be within ____% of the FLC on the nameplate.
10%
IEC motors are rated in ____.
Kilowatts
