Flashcards in Motor Control 3 Deck (99)
What are the 3 types of DC motors?
How many SETS of contacts do DC motors utilize?
1 Set (2 Contacts)
Rheostats are ____ control devices, meaning a person has to be there to operate it.
How do Rheostats change motor speed?
By changing the amount of current to the armature. (To which it is usually wired in series)
____ are a safety feature for maintaining connection after motor speed has reached maximum.
T/F: Contactor starting connects partial voltage when first connected.
False, full voltage is connected across the contacts.
____ are segments that cool and separate arcs. Usually 80% of the energy is absorbed.
A ____ creates a magnetic field that extinguishes the arcs.
What are 3 ways that drives are better than rheostats>
1.) No human required to operate
2.) Less power to operate
3.) Cheaper in the long run
Motor speed monitoring is done with what 2 devices?
How do you reduce the speed of a DC motor?
Reduce Armature voltage
How do you increase the speed of a DC motor?
Reduce field winding voltage
What are the two parts of a DC drive?
1.) Power section
2.) Control section
How does the control section of a DC drive control motor speed?
By quickly switching to dictate how much of the power is delivered to the motor, and when.
___-loop control has motor characteristics pre-programmed into the controller.
Open-loop, which is cheaper.
____-loop control uses sensors to monitor motor characteristics, adjusting as needed.
What are the two types of DC motor braking?
(Except for Friction Braking)
1.) Dynamic - Braking Resistors
2.) Regenerative - Back to power source
What is the most common analog range?
What are the two reasons that using 4-20mA is the most common analog range?
1.) Longer range (Current, no voltage drop)
2.) Less to no issues from electrical noise.
What are the three types of analog signals?
1.) Current (4-20mA)
2.) Voltage (0-5vDC, 1-5vDC)
3.) Pressure (3-15PSI)
A ____ converts a signal to one that is more usable by the device.
Limit Alarms are also known as ____.
How can you use a 1-5vDC device with a 4-20mA system ?
With a 250 Ohm Resistor.
A ____ converts one type of energy to another, usually for reading/signal purposes.
What are the two parts of a transducer?
What are the two types of temperature sensors that vary resistance with temperature?
What are the 2 types of temperature sensors that produce a small voltage when heated?
2.) Solid State Temperature Sensors
Wires coming off of a thermocouple must be as short as possible to mitigate voltage drop, so they are usually ran to a nearby ____.
What are the 3 Position Sensing devices?
1.) Linear Potentiometers
2.) Rotary Potentiometers
3.) LVDT (Movable Core)
What are the 6 Pressure Sensor types mentioned in the book?
3.) Bourden Tube
5.) Direct (Strain Gauge + Load Cell)
6.) Solid State
What are the 6 types of Flow sensors that the book mentions?
1.) Paddle Wheel
6.) Mass (Thermal + Coriolis)
A Vortex-type flow sensor contains a component called the ____ which contacts the liquid to create vortices, which are utilized for measuring flow.
Ultrasonic-type flow sensors utilize ____ in the fluid they are reading, for receiving sound waves back.
Current Sinking, NPN or PNP?, switch on the positive or negative side?
Sinking = NPN = switches on the Negative side.
Current Sourcing, NPN or PNP?, switch on the positive or negative side?
Sourcing = PNP = switches on the positive side.
How is an AC/DC input module able to utilize AC power?
Because it has Reverse parallel diodes.
T/F: TTL input modules are heavy duty.
What are the 4 types of input modules?
1.) Current Sinking
2.) Current Sourcing
What are the 3 types of output modules?
1.) DC Output (Current sinking)
2.) AC Output (Uses Triacs)
T/F: Grounds should go elsewhere other than the drive, so any possible fault current or ESD stays away from the boards.
What does ESD stand for?
Most "smart" or Solid State devices have ____-diagnostic capabilities.
____(s) give absolute control of a motor through modulation, use much less energy than older starting technologies and are cheaper in the long run
T/F: VFD's allow control of motor speed, torque, direction, and stopping.
What are some things to consider when SELECTING a VFD for installation?
1.) Speed desired
5.) Horsepower Rating
The feedback loop from speed sensors is a(n) ____ type signal, and it cannot be run with power feeds to motor.
____(s) act like isolation transformers to mitigate harmonics put out by the VFD during the course of modulation.
T/F: It isn't important to consider power quality before installing a VFD.
____(s) protect the VFD from the elements and also protect personnel from coming into contact with energized parts.
T/F: Wiring connections aren't very important.
T/F: The motor must be grounded to the VFD's internal grounding terminal.
There are four main areas to check for issues when troubleshooting a VFD, what are they, in-order?
4.) Internal Components
A ____ is an industrial-grade computer, with one dedicated purpose or chore.
What is the most common programming language that is used with PLC's?
In what ways are PLC's and PC's similar?
4.) Expansion Slots
How are PLC's and PC's different?
PLC's are not pre-programmed, nor do they have removable storage media.
What are the three ways to program a PLC?
2.) Buttons on the unit
3.) Handheld programmer
What program does the Allen-Bradley SLC 500 'family' of PLC's operate on?
____ PLC's aren't able to be modified, all inputs and outputs are already built in.
T/F: The MicroLogix 1000 is a standalone unit.
The ____ is the box or cabinet that the rack (chassis) is mounted to.
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
What are the three types of OUTPUT signals?
T/F: Regular I/O modules can be used for stepper and servo motors.
____ manufacturing produces consumables such as food, gas, paint, paper, and chemicals.
____ manufacturing produces durable goods such as automobiles, fridges, and components used in larger and smaller products.
Discrete Parts Manufacturing
T/F: Synchronous motors have no slip.(After they are brought up to speed)
T/F: Induction motors are more expensive than synchronous motors.
False, synchronous are more expensive because they can be more precisely controlled.
____ motors are best suited for Direct Drive, High Horsepower, or Low RPM Loads.
What are the 2 phases of synchronous motor starting?
2.) Attaining Synchronous Speed
____ motors use discrete inputs (Electronic Digital Pulses) to position the motor. This can be done clockwise or counter-clockwise with very precise control.
What is stepping rate?
The maximum amount of steps in one second.
What is Step Angle?
The amount of rotation per pulse.
What is Holding torque?
The maximum load torque with the stator energized.
What is Detent Torque?
The maximum load torque with the stator de-energized.
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.
A ____ Network is a group of locally connected machines in a company building or group of buildings.
A ____ is used as a data highway within an enterprise network.
LAN (Local Area Network)
A ____ network links branch offices and single mobile users to a local enterprise network or the internet.
A ____ network is comprised of connected enterprise networks.
What are the 4 types of network cabling discussed in the book?
A ____ is a multiport repeater, similar to a signal booster
____ are also called "Network Media" and are the physical path on which electrical and optical signals travel.
____(s) are high power workstations with a specific purpose.
A ____ connects a device to the network.
____(s) are devices such as printers, plotters, fax machines, and backup devices.
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.
What are 4 things to consider when selecting Network Media?
3.) Noise Immunity
Unshielded Twisted Cable (UTP), which is used for most ethernet wiring, is divided into 6 different designations (ratings) what are they?
What are the three Network Topologies?
1.) Bus - Central Network Media
2.) Ring - Connected in loop shape
3.) Star - One Central Cluster and hub.
Ethernet consists of what 3 parts?
1.) Physical Cable
2.) Network Rules
3.) Standard Data Packet
____ is a medium level control network for automation. It does NOT carry device power.
____ is the lowest level of base integration devices. It carries the device power in the same cable.
Cable ____(s) prevent the data in the cable from reflecting back off of the end points of the cable.
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
____ diagrams use rectangles to identify parts of a system.
Signal flow is divided into ____ and ____.
Power and Information
What are the 5 Line types in a block diagram?
5.) Switched Path