Motor Control 3 Flashcards
1
Q
What are the 3 types of DC motors?
A
- ) Series
- ) Shunt
- ) Compound
2
Q
How many SETS of contacts do DC motors utilize?
A
1 Set (2 Contacts)
3
Q
Rheostats are ____ control devices, meaning a person has to be there to operate it.
A
Manual
4
Q
How do Rheostats change motor speed?
A
By changing the amount of current to the armature. (To which it is usually wired in series)
5
Q
____ are a safety feature for maintaining connection after motor speed has reached maximum.
A
Holding Coils
6
Q
T/F: Contactor starting connects partial voltage when first connected.
A
False, full voltage is connected across the contacts.
7
Q
____ are segments that cool and separate arcs. Usually 80% of the energy is absorbed.
A
Arc Chutes
8
Q
A ____ creates a magnetic field that extinguishes the arcs.
A
Blowout Coil
9
Q
What are 3 ways that drives are better than rheostats>
A
- ) No human required to operate
- ) Less power to operate
- ) Cheaper in the long run
10
Q
Motor speed monitoring is done with what 2 devices?
A
- ) Tachometer
2. ) Encoder
11
Q
How do you reduce the speed of a DC motor?
A
Reduce Armature voltage
12
Q
How do you increase the speed of a DC motor?
A
Reduce field winding voltage
13
Q
What are the two parts of a DC drive?
A
- ) Power section
2. ) Control section
14
Q
How does the control section of a DC drive control motor speed?
A
By quickly switching to dictate how much of the power is delivered to the motor, and when.
15
Q
___-loop control has motor characteristics pre-programmed into the controller.
A
Open-loop, which is cheaper.
16
Q
____-loop control uses sensors to monitor motor characteristics, adjusting as needed.
A
Closed-loop
17
Q
What are the two types of DC motor braking?
Except for Friction Braking
A
- ) Dynamic - Braking Resistors
2. ) Regenerative - Back to power source
18
Q
What is the most common analog range?
A
4-20mA
19
Q
What are the two reasons that using 4-20mA is the most common analog range?
A
- ) Longer range (Current, no voltage drop)
2. ) Less to no issues from electrical noise.
20
Q
What are the three types of analog signals?
A
- ) Current (4-20mA)
- ) Voltage (0-5vDC, 1-5vDC)
- ) Pressure (3-15PSI)
21
Q
A ____ converts a signal to one that is more usable by the device.
A
Signal Conditioner
22
Q
Limit Alarms are also known as ____.
A
Level-Relays
23
Q
How can you use a 1-5vDC device with a 4-20mA system ?
A
With a 250 Ohm Resistor.
24
Q
A ____ converts one type of energy to another, usually for reading/signal purposes.
A
Transducer
25
What are the two parts of a transducer?
1. ) Sensor
| 2. ) Transmitter
26
What are the two types of temperature sensors that vary resistance with temperature?
1. ) RTD
| 2. ) Thermistor
27
What are the 2 types of temperature sensors that produce a small voltage when heated?
1. ) Thermocouples
| 2. ) Solid State Temperature Sensors
28
Wires coming off of a thermocouple must be as short as possible to mitigate voltage drop, so they are usually ran to a nearby ____.
Reference block.
29
What are the 3 Position Sensing devices?
1. ) Linear Potentiometers
2. ) Rotary Potentiometers
3. ) LVDT (Movable Core)
30
What are the 6 Pressure Sensor types mentioned in the book?
1. ) Deflection
2. ) Differential
3. ) Bourden Tube
4. ) Piezoelectric
5. ) Direct (Strain Gauge + Load Cell)
6. ) Solid State
31
What are the 6 types of Flow sensors that the book mentions?
1. ) Paddle Wheel
2. ) Turbine
3. ) Vortex
4. ) Electromagnetic
5. ) Ultrasonic
6. ) Mass (Thermal + Coriolis)
32
A Vortex-type flow sensor contains a component called the ____ which contacts the liquid to create vortices, which are utilized for measuring flow.
Bluff-Body
33
Ultrasonic-type flow sensors utilize ____ in the fluid they are reading, for receiving sound waves back.
Particulates
34
Current Sinking, NPN or PNP?, switch on the positive or negative side?
Sinking = NPN = switches on the Negative side.
35
Current Sourcing, NPN or PNP?, switch on the positive or negative side?
Sourcing = PNP = switches on the positive side.
36
How is an AC/DC input module able to utilize AC power?
Because it has Reverse parallel diodes.
37
T/F: TTL input modules are heavy duty.
True
38
What are the 4 types of input modules?
1. ) Current Sinking
2. ) Current Sourcing
3. ) AC/DC
4. ) TTL
39
What are the 3 types of output modules?
1. ) DC Output (Current sinking)
2. ) AC Output (Uses Triacs)
3. ) TTL
40
T/F: Grounds should go elsewhere other than the drive, so any possible fault current or ESD stays away from the boards.
True
41
What does ESD stand for?
Electrostatic Discharge
42
Most "smart" or Solid State devices have ____-diagnostic capabilities.
Self-diagnostic
43
____(s) give absolute control of a motor through modulation, use much less energy than older starting technologies and are cheaper in the long run
VFD's
44
T/F: VFD's allow control of motor speed, torque, direction, and stopping.
True
45
What are some things to consider when SELECTING a VFD for installation?
1. ) Speed desired
2. ) Torque
3. ) Direction
4. ) Stopping
5. ) Horsepower Rating
46
The feedback loop from speed sensors is a(n) ____ type signal, and it cannot be run with power feeds to motor.
Analog
47
____(s) act like isolation transformers to mitigate harmonics put out by the VFD during the course of modulation.
Line reactors
48
T/F: It isn't important to consider power quality before installing a VFD.
False
49
____(s) protect the VFD from the elements and also protect personnel from coming into contact with energized parts.
Enclosures
50
T/F: Wiring connections aren't very important.
False
51
T/F: The motor must be grounded to the VFD's internal grounding terminal.
True
52
There are four main areas to check for issues when troubleshooting a VFD, what are they, in-order?
1. ) Inputs
2. ) Outputs
3. ) Program
4. ) Internal Components
53
A ____ is an industrial-grade computer, with one dedicated purpose or chore.
PLC
54
What is the most common programming language that is used with PLC's?
Ladder-Logic
55
In what ways are PLC's and PC's similar?
1. ) Processors
2. ) Memory
3. ) Motherboard
4. ) Expansion Slots
56
How are PLC's and PC's different?
PLC's are not pre-programmed, nor do they have removable storage media.
57
What are the three ways to program a PLC?
1. ) PC
2. ) Buttons on the unit
3. ) Handheld programmer
58
What program does the Allen-Bradley SLC 500 'family' of PLC's operate on?
RS Logix500
59
____ PLC's aren't able to be modified, all inputs and outputs are already built in.
Stand-alone
60
T/F: The MicroLogix 1000 is a standalone unit.
True
61
The ____ is the box or cabinet that the rack (chassis) is mounted to.
Backplane
62
What is the metal rail that the processor/power supply and I/O modules are mounted on in a modular PLC system?
The Rack, or Chassis
63
What are the three types of OUTPUT signals?
1. ) Analog
2. ) Discrete
3. ) Digital
64
T/F: Regular I/O modules can be used for stepper and servo motors.
False
65
____ manufacturing produces consumables such as food, gas, paint, paper, and chemicals.
Process manufacturing
66
____ manufacturing produces durable goods such as automobiles, fridges, and components used in larger and smaller products.
Discrete Parts Manufacturing
67
T/F: Synchronous motors have no slip.(After they are brought up to speed)
True
68
T/F: Induction motors are more expensive than synchronous motors.
False, synchronous are more expensive because they can be more precisely controlled.
69
____ motors are best suited for Direct Drive, High Horsepower, or Low RPM Loads.
Synchronous
70
What are the 2 phases of synchronous motor starting?
1. ) Start-Up
| 2. ) Attaining Synchronous Speed
71
____ motors use discrete inputs (Electronic Digital Pulses) to position the motor. This can be done clockwise or counter-clockwise with very precise control.
Stepper
72
What is stepping rate?
The maximum amount of steps in one second.
73
What is Step Angle?
The amount of rotation per pulse.
74
What is Holding torque?
The maximum load torque with the stator energized.
75
What is Detent Torque?
The maximum load torque with the stator de-energized.
76
A ____ is a motor similar to a stepper motor, but with a feedback loop for monitoring exactly how much the shaft has rotated, so corrections can be made.
Servo-motors.
77
A ____ Network is a group of locally connected machines in a company building or group of buildings.
Enterprise
78
A ____ is used as a data highway within an enterprise network.
LAN (Local Area Network)
79
A ____ network links branch offices and single mobile users to a local enterprise network or the internet.
Remote
80
A ____ network is comprised of connected enterprise networks.
Wide-Area
81
What are the 4 types of network cabling discussed in the book?
1. ) UTP
2. ) STP
3. ) Coax
4. ) Fiber
82
A ____ is a multiport repeater, similar to a signal booster
Hub
83
____ are also called "Network Media" and are the physical path on which electrical and optical signals travel.
Cables
84
____(s) are high power workstations with a specific purpose.
Servers
85
A ____ connects a device to the network.
Interface Card.
86
____(s) are devices such as printers, plotters, fax machines, and backup devices.
Peripherals
87
What is an HMI and what does it do?
Human-Machine-Interface, and it is the medium between human operators and the device/system. Displays system parameters and allows an operator to make changes.
88
What are 4 things to consider when selecting Network Media?
1. ) Range
2. ) Bandwidth
3. ) Noise Immunity
4. ) Cost
89
Unshielded Twisted Cable (UTP), which is used for most ethernet wiring, is divided into 6 different designations (ratings) what are they?
```
CAT3
CAT4
CAT5
CAT5E
CAT6
CAT7
```
90
What are the three Network Topologies?
1. ) Bus - Central Network Media
2. ) Ring - Connected in loop shape
3. ) Star - One Central Cluster and hub.
91
Ethernet consists of what 3 parts?
1. ) Physical Cable
2. ) Network Rules
3. ) Standard Data Packet
92
____ is a medium level control network for automation. It does NOT carry device power.
Control-Net
93
____ is the lowest level of base integration devices. It carries the device power in the same cable.
Device-Net
94
Cable ____(s) prevent the data in the cable from reflecting back off of the end points of the cable.
Terminators
95
What is the six step troubleshooting sequence?
1. ) Define the Problem
2. ) Decide what needs to be tested
3. ) Decide what type of test should be performed
4. ) Correct the Problem
5. ) Verify Correct Operation
6. ) Determine the cause of failure
96
____ diagrams use rectangles to identify parts of a system.
Block
97
Signal flow is divided into ____ and ____.
Power and Information
98
What are the 5 Line types in a block diagram?
1. ) Linear
2. ) Convergent
3. ) Divergent
4. ) Feedback
5. ) Switched Path
99
____ is a four step method to work your way down to the issue.
Information Funneling
