1PH Motors And Auxiliary Controls Final Test
How many windings does the stator of a shaded-pole motor have?
1
an electronically commutated motor(ecm), also known as a variable speed motor operates at lower amps of the same size PSC motor. Approximately how much lower?
1/3
The microfarad rating of a replacement capacitor must be within +/- _____________ % of the original capacitor
10
starting components are designed to remove the start winding or start capacitor from the motor circuit when the motor reaches ________% of speed
75
AC motors typically come with ______________ poles
All of the above (2,4,6,8)
What type of bearings may a motor have?
All of the above (ball, roller, sleeve)
What are the ends of the motor referred to as?
All of the above (end plates, end bells, end shields)
Standard types of motor enclosures on AC motors include:
All of the above (open, totally enclosed, explosion proof)
What can cause cycling on the overload?
All of the above(excessive amp draw, excessive motor heat, excessive compressor heat)
What is a big enemy of AC motors?
All of the above(moisture, heat, over-lubrication)
After installing a new motor, the technician should always check the motor's ____________
Amp draw
Which of the motors below has the best starting torque?
Capacitor start
This electrical diagram is an example of a ___________
Capacitor start motor
A belt-driven air handler using a split-phase motor will usually be equipped with a _________ to remove the start winding on motor start-up
Centrifugal Switch
Which of the motors below is the most efficient?
ECM
AC motors provide superior torque and speed control over DC motors.
False
Because of the heat-activated varnish insulation on motor windings, over lubrication of electric motors is not a problem
False
In AC motors, a two pole AC motor runs slower than a four pole AC motor
False
Shaded-pole motors have both a run and start winding.
False
Supply voltage for a motor must be within +/- 20% of a nameplate voltage
False
The more poles a motor has the lower its torque will be.
False
The most common AC motors have three or seven poles in the stator
False
The two sets of windings found in the stater of an AC motor are called the run and walk windings
False
an electrical motor accepts mechanical energy as rotation and torque and converts it into electrical energy as voltage and current
False
over lubrication of motors:
Is deadly to electric motors
When an AC motor is first energized, it will immediately draw _________ amps
Locked-Rotor
what is meant by the term "impedence protected" on the nameplate of a motor
Motor will not draw excessive current when overloaded or stalled.
The contacts on a potential relay with no power applied would _________
Normally closed
The contacts on a current relay with no power applied would _________
Normally open
This electrical diagram is an example of a ___________
PSC
Which of the motors below must be equipped with a run capacitor?
PSC
which of the motors below is available in multi speed applications of up to six speeds
PSC
All motors must produce _________
Rotation
What type of capacitor, usually has a metal case and is designed to always be in the motor circuit
Run
Capacitors are always connected in ________ with the start winding
Series
Which of the motors below requires no centrifugal switch or start relay?
Shaded Pole
which of the motors below does not have a start winding
Shaded Pole
what are the motors below can be considered to be "impedance protected"
Shaded pole
This electrical diagram is an example of a ___________
Shaded pole motor
since most motors produce torque, the motor shaft will typically run 3% slower than the stator synchronous speed. What do you call this speed difference?
Slip
An eight pole motor will run ______ than a two pole motor
Slower
Which of the motors below can be used in belt applications?
Split phase
This electrical diagram is an example of a ___________
Split phase motor
In some AC motors; the second winding on the stator, known as the ___________ winding, is rated for intermittent duty only.
Start
On a PSC motor, whenever you replace the motor you should also replace what part?
The capacitor
What is the stationary part of the AC motor is called?
The stator
All AC motors should be equipped with _______ delay fuses or circuit breakers
Time
The induction principle with AC motors is similar to what other part?
Transformers
A motor is considered overloaded if its amp draw is more than 10% over nameplate full load amps (FLA)
True
A two speed motor will usually have more windings than a one speed motor
True
AC motors are simpler and construction than DC motors
True
Heat-activated varnish applied to stator coils help exclude moisture and contaminants and act as motor winding insulation
True
Magnetic opposition and attraction produced between the stator and rotor usually results in rotation of the motor shaft
True
Most AC motors run at nearly a constant speed that is set by the number of poles and the supply frequency
True
On most small fractional horsepower motors, the end bells are secured by a set of bolts that extend through the motor from end to end
True
The poles of the start winding, on a AC stator, are typically centered halfway between the poles of the first windings
True
The rotating part of all AC motors is referred to as the rotor
True
The type of electric motors used in the residential HVAC industry are typically fractional horsepower motors
True
When replacing a fractional horsepower motor, its frame size is determined by measuring the motor's diameter.
True
if a motor used for air handling is not installed in the airflow, it must be equipped within an internal, shaft mounted fan for proper cooling
True
in some AC stators, the start winding is easily identifiable because it is wound with a lighter gauge of wire than the first winding
True
it is acceptable to replace a 5 uF capacitor rated at 370 VAC with a 5 uF capacitor rated at 440 VAC
True
squirrel-cage rotors are the most widely used rotor types in AC motors
True
