electric motors Flashcards
What percentage of all electricity generated is consumed by electric motors?
50%
Electric motors are prevalent in both domestic and industrial applications.
What are the two main parts of an electric motor?
Stator and rotor
The stator is the non-rotating part, while the rotor is the part that spins.
What is the function of the commutator in a DC motor?
To continually reverse the current through the coil
Simple commutators have two segments, while real motors have more.
What component is used to conduct current from the supply through the commutator?
Carbon brushes
They ensure the flow of current to the coils.
What creates the magnetic field in small DC motors?
Permanent magnets
These are found in the stator.
How do large DC motors produce their magnetic field?
Field coils in the stator
The field can be series wound or shunt wound.
What is the difference between series wound and shunt wound DC motors?
Series wound has field connected in series; shunt wound has field coils in parallel
This affects the motor’s operation and characteristics.
What principle do AC motors operate on?
Electromagnetic induction
This is especially true for three-phase AC motors.
What generates a rotating magnetic field in a three-phase AC motor?
Three-phase supply applied to the stator
This setup includes three sets of coils.
What is synchronous speed in a motor?
The speed at which there is no difference between rotor and rotating field speed
At this speed, no voltage is induced in the rotor, resulting in no torque.
What type of AC motors are popular for domestic appliances?
Single phase AC motors
Commonly used in washing machines, fans, electric drills, and fridges.
Fill in the blank: The rotor is the part that ______ within the motor.
spins or rotates
This is a crucial function of the rotor.
Fill in the blank: A stator is the stationary part found within ______.
electric motors
It contrasts with the rotating rotor.
