Motor controls 3 test review
Commonly used Ethernet media types are
100baseT-UTP
Dynamic braking
A motor braking technique where the motor is operated as a DC generator after main power is removed
Four most common input circuits
AC/DC, DC sinking, DC sourcing, transistor transistor logic
? Signals are converted between volts, amperes, or pressure by signal conditioning devices to match the input requirements
Analog
A ? Signal is a continuous value (0-5v)
Analog
All machines are connected to a central network media and is also called the backbone
Bus topology
Prevent the data moving through the cable from reflecting back at the end points
Cable terminators
Motor speed and torque data are automatically fed back to the VFD
Closed loop system
A ? Converts a 4 to 20 ma analog signal to a proportional and linear 3 to 15 psi output
Current to pressure converter
What are some pressure sensing devices
Deflection and differential pressure sensors, piezoelectric and solid state sensors, and direct pressure sensors
What provides a visual image of a system with smart input devices connected to a device level network
DeviceNet
A ? Signal has an on and off state(0v or 5v)
Discrete
What is the rapid flow of electrons between two bodies of unequal charge
Electrostatic discharge
What occurs between one charged body and ground with an electronic circuit being path of least resistance between the two
Electrostatic discharge
Examples of constant torque loads
Hoist, conveyors, and printing presses
The maximum load originating torque that the motor stand without moving from its position with the stator energized
Holding torque
Central connecting devices in a network that are sometimes called a multiport repeaters
Hubs
What is used to lessen the impact of harmonics generated by VFDs inductors
Line reactors
? Is a linear position sensing device consisting of transformer with a moveable core
Linear variable differential transformer
5 types of signal flow topologies
Linear, divergent, convergent, feedback, and switched paths
A common application for strain gages is a weight measuring devices called?
Load cell
A PC and PLC are similar with both featuring?
Motherboard, processor, memory, and expansion slots
What system for a VFD has no feedback data for motor speed or torque
Open loop system
What is the heart of a PLC
PLC processor
? Is a temperature sensing device that exhibits a change in resistance
Resistance temperature detector
All machines are interconnected in the shape of a closed loop
Ring topolgy
Used to segment LANs in order to balance traffic within workgroups and are used as firewalls
Routers
Troubleshooting smart systems is aided by the ? Of the smart devices
Self diagnostic capabilities
What are the 3 wiring configurations for DC motors
Series, shunt, and compound
High powered workstations with a specific function
Servers
A position or motion correcting motor that responds to a control signal
Servo motor
All machine clusters are typically connected to a hub or switch
Star topolgy
Devices designed to detect tensile and compression change are called?
Strain gages
Most common type of sensor
Strain gages
A three phase motor in which a rotor turns at the same speed as the magnetic field of the stator
Synchronous motor
? Is a physical property of a system that describes degrees of hot and cold
Temperature
Starter rheostat
The ? Limits armature current in the motor during starting and accelerating
? Are temperature sensing devices that produce a millivolt level voltage when the temperature increases
Thermocouples
What is the name of two or more thermocouples connected in series
Thermopile
A ? Converts a variable such as temperature, position, flow, or pressure into an analog signal that is used by the control system
Transducers
Regenerative braking
What returns the regenerated power of a DC motor back to the power source
Remove foreign material, brushes move freely in the holder, spring tension is equal on every brush, and commutator has a properly polished surface
What should you check for when troubleshooting DC motor
Examples of constant horsepower
Winders, core driven reels, wheel grinders
