Actuators Flashcards
What is a relay?
An electromagnetic switch which turns on or off a much larger electric current.
Eg. ACOS, RICS
What is a solenoid?
An actuator assembly with a sliding ferromagnetic plunger inside the coil. Extended when de-energized.
Can be used as an actuator, switch, or valve.
Electric Actuators: How do we prevent the actuator from being forced backward?
Break and mechanical advantage.
If a DC motor did did not have a split ring commutator, in what position would the rotor be?
Perpendicular to the magnetic field.
The speed of the AC motor depends on:
Frequency of the AC supply
What is “slip” in an AC motor?
The greater the load, the greater the “slip” between the speed of the rotating magnetic field and actual speed of the rotor.
What is the advantage of AC motors?
Simplicity. Only one moving part. Easy to transform the power output.
What is a pro and con of DC motors?
Pro: Instant torque, easy to switch directions.
Con: Friction, maintenance, noise, complex
How is the speed controlled on an AC motor?
Turns at a constant speed unless you use a variable-frequency drive.
How do you control the speed of DC motors?
Vary the voltage
