General Flashcards
Motors convert electrical energy into what?
Mechanical energy.
What is a PSC motor?
Permanent split.
How many windings are in a single phase motor?
Two, start and run.
What are the 4 parts of a single phase motor?
Stator, frame, rotor/shaft and the end bells.
Where are the run windings located?
At the bottom of the stator slots.
When are the run windings connected?
They are connected continiously.
Do the run windings have a large, or small conductor?
A large conductor.
Where is the start winding found?
In the top of the stator slots.
When are the start windings disconnected from the circuit?
When the motor reaches 75 percent of its rated speed.
Does the run or start winding have more resistance?
The start winding has more resistance.
Is a centrifugal switch normally opened or normally closed?
A centrifugal switch is normally closed.
In which motor is the start winding de-energized after the motor reaches 75 percent of its rated speed?
RSIR or resistive start induction run motor.
Which motor has about 300 percent more starting torque than running torque?
CSIR or capacitor start induction run motor.
In a CSCR motor, is the run or start capacitor disconnected when the motor reaches 75 percent of it’s rated speed?
The start capacitor is removed from the circuit.
What are the characteristics of a PSC motor?
Both windings and capacitor stay in the circuit continuously, and the run capacitor is oil filled.
What is unique about a shaded pole motor?
It has a shading coil that creates a small amount of MMF in the core.
Is a high voltage motor connected in series, or parallel?
A high voltage motor is connected in series.
Is a low voltage motor connected in series or parallel?
A low voltage motor is connected in parallel.
Which relay uses a low resistive coil and and a set of normally open contacts?
The current relay.
Which motor uses a potential relay?
A potential relay is found with a CSCR motor.
A 2 pole contactor has how many loads?
One single phase load.
A 3 pole contactor has how many loads?
Three, single phase loads.
What is a motor starter?
A contactor plus over-loads is a motor starter.
What is the SI measurement for torque?
The newton.
What is connected in series with the start winding?
The start capacitor.
A motor with a service factor of less than 1.15 has the overloads set to what?
115% of it’s rated FLA.
A motor with a service factor of more than 1.15 has the overloads set to what?
125% of it’s rated FLA.
How do you wire multiple start buttons?
In parallel.
How do you wire multiple stop buttons?
In series.
What are three things required to create an AC voltage?
A magnetic field, a current carrying conductor, and relative motion.
What does a transformer consist of?
Two windings, and one common core.
What motor has the lowest starting torque?
The RSIR motor.
What motor has the highest starting torque?
The CSIR motor.
Which motor has the lowest starting current?
The CSCR motor.
Which motor has the run cap left in at all times?
The PSC motor.
Does a shaded pole motor have high, or low torque?
Very small amounts of torque.
How is a potential relay wired?
In parallel with with the start winding. Disconnects the start cap while running. Known as the 5,2,1 relay.
How is a current relay wired?
In series with the run winding. and has N/O contacts. Attaches directly to the compressor terminals.
Does a potential relay have a low, or a highly resistive coil?
It has a low resistive coil.
Which motor has the highest starting torque, the lowest current, and is the most expensive?
CSCR (Capacitor start, capacitor run)
Which capacitors are electrolytic and designed to only be in the circuit for a few seconds?
Start capacitors.
What motor is the most suitable as a belt driven motor, and why?
The CSIR motor, because of it’s high starting torque.
What section describes class 1 and 2 circuits?
Section 16.
What are extra low voltage power circuits restricted to?
A maximum of 30V and a maximum power level of 1000 vA.
What are class 1 remote control circuits limited to?
A maximum of 600V.
What section of the CEC covers the Scope?
Section 16-000.
What is the formula for line voltage?
Phase voltage x 1.732
What is considered extra low voltage?
0-30 VAC
What is considered low voltage?
600-1000 VAC
What is considered high voltage?
Over 1000 VAC
What does a signal circuit energize?
A bell, or a light.
What does a remote control energize?
A relay coil or a contactor.
