Motor Basics
The two principal parts of an AC induction motor are the:
Rotor and stator
Compared to the stator's magnetic field, the rotor's magnetic field is:
Opposite in polarity.
This type of AC motor is characterized by low starting torque and is suitable for light applications such as refrigerator evaporator motors
Shaded Pole
What is the primary purpose of the start capacitor?
To increase the motor starting torque
A technician has installed a new three-phase motor, but it is running in reverse. What should she do to correct the rotation?
Reverse two motor power supply leads.
The part of an AC induction motor that turns is called:
Rotor
The rotor consists of:
Aluminum bars mounted on a laminated soft iron core.
Compared to the run winding, the start winding is constructed of
Smaller gauge wire than the run winding.
Why are capacitors rated at higher voltages than the unit line voltage
Charging and discharging in series with an inductive load subjects them to high voltage.
Compared to single-phase motors, three-phase motors are:
Stronger starting with a higher operating efficiency.
The part of an AC induction motor that induces the current flow in the rotor is called:
Stator
The rotor turns because of:
The repulsion and attraction between the poles of the rotor and stator.
AC induction motor speed is determined by the current frequency (Hz) and the number of:
Poles
What is the primary purpose of the run capacitor?
To increase the motor efficiency
The windings of a three-phase motor are:
120 degrees apart
The rotor consists of:
Aluminum bars mounted on a laminated soft iron core.
The magnetic field of the stator is
Opposite in polarity as the rotor magnetic field.
The twisting force that must be developed by a motor to turn its load is called:
Torque.
The start capacitor for fractional horsepower, open-type capacitor start motors is removed from the circuit by:
A centrifugal switch.
A major difference between three-phase motors and single-phase motors is that:
Three-phase motors do not need any type of starting components.
How does the rotor of an AC induction motor receive current
Rotor current is induced by the rotor magnetic field.
All single-phase motors need to create an additional magnetic field that:
Is out of phase with the magnetic field of the main winding to get the motor started
5) When operated with the same power source, which induction motor will have a higher RPM: a four-pole motor or a six-pole motor?
a four pole
The proper way to discharge a capacitor is to
Connect a bleed resistor across the terminals
What happens when a three-phase motor tries to operate on only two legs of power?
The motor overheats.