AC Motors Flashcards
What are the 2 AC types that motors can be available in?
- Single phase
- 3 phase
Different voltages like 115, 208, 230 etc just depend on what?
The transformer being used
What do more poles in the motor do?
Lower the rpm and raise torque
What are some factors that can make a motor overheat?
Clogged fins, voltage fluctuation, overloading, high ambient Temps, repeated starts and stops
Because of motors being manufactured by nema what are is some information you can give when ordering a new one if you don’t have a motor data plate?
Shaft center line and bolt pattern
What on the data plate would give you the insulation value?
Motor class
What is the definition of service factor?
The amount of overload a motor can take before overheating
What is the most common service factor for a motor?
1.0
What the service factor goes up what has to go up with it?
Motor class
If rpms are low what are torque and current?
High
2 types of mounting styles ?
- C-face
- D-flange
How to know if it is a c-frame mount?
Driven unit is bolted to the motor
How to know if it’s a D-flange mount?
Motor is bolted to driven
What protects a motor?
Overloads
What does mto and ato stand for?
Manual and automatic thermal overloads
What are the parts of an ac motor?
Rotor, stator, end bells, fan, fan shroud and shaft
Why are ac motors the go to of the industry?
High efficiency, cheaper cost and start up torque
What is the slip in a motor?
The difference between synchronous speed and actual speed?
Biggest downside of a single phase motor?
There is no start up torque
What do we know about shaded pole motors?
The motor rotates in the direction of the shading ring
What do we know about split phase motors?
Once it reaches the full rpm a switches kicks out the starting windings
Most common single phase motor used in industrial applications?
Capacitor start motor
Permanent split capacitor motors are common for what?
Changing speed and direction of a fan
