Motor Control Flashcards
The question mark sensor
Bourdon tube sensor
Types of pressure switches
Bourdon tube
Bellows
Diaphragm
Pressure switch with springs in it
Bellows
Pressure switches commonly used for
Safety devices to protect system from high or low pressures
What is the differential of a pressure switch.
The difference between the cut in and cut out pressure of the switch.
What is the range of a pressure switch
The overall pressure over which a switch can operate
Float switches are also called
Liquid level switches.
Temperature switch (thermostat) are used for
Automatic control in heating and cooling systems.
How are most temp switches constructed?
Bimetallic strips.
What are mechanical limit switches used for.
Prevent over travel and used in reversing motor applications.
Maintained contact limit switch
Have contacts that remain in position even though the force is removed.
Timed contacts limit switch
Have a delay between the time the operating mechanism is moved and the time the contacts operate.
Photoelectric switch.
Prox sensors that contain a beam transmitter and a receiver. (Garage door)
What makes up a control relay?
Electromagnetic coil
One or more sets of contacts.
Why to use control relays
Used as aux contacts to switch low-level currents.
Contacts rating
10 amps As high as 600v Inrush or make rating Normal or continuous rating Opening or break contact rating
On delay relay
Time delay occurs after the relay is energized.
Off delay relay
Time delay occurs when relay is de energized.
Different types of timers
Dashpot
Pneumatic
Motor driven
Electric
Electric timers use what in the base.
Alignment key
Why would you use control relays with motor starters?
Add more aux contacts
Rating of 10 amps on a relay is
Continuous current
What is a latching relay
A relay that is electronically activated and mechanically held.
Oil filled pot and piston associated with.
Dashpot timer
The movement of air using bellows or diaphragm assembly is associated with
Pneumatic timer
What type of timer best used for switching a motor on and off at 1 hour intervals
Motor driven timer
What fundamental principal do electric timers use?
R-C time constant
Which time delays have instantaneous contacts?
Either type can have timed or instantaneous.
What is plugging
Quickly stopping a motor
How do you plug a motor.
Try and reverse the motor and then stop before it can turn in the opp direction.
Another name for plugging switch
Zero speed switch
What is the purpose of the lockout relay in a plugging switch
“Safety latch” holds the contacts open until motor control circuit has been energized.
What is anti-plugging.
Using a zero speed switch on reversing motor drive so the motor can’t be reversed until it’s stopped.
An industrial temperature switch that utilizes a fluid filled temperature sensor is called a…
Remote bulb switch
