Single Phase Motor Review
6 pole?
1200rpm
4 pole?
1800rpm
A motor has a voltage rating of 210 - 240 what would be the minimum and maximum voltages that could be applied to this motor?
200-264 volts
What is the synchronous speed of a single phase two pole 60hz AC motor?
3600rpm (60 cycles x 60 sec/min)
8 pole?
900rpm
How does a PTC relay work? PTC = Positive Temp Coefficient
As temperature rises, resistance increases
Two capacitors connected in series C1 = 15mfd, 220 volts, C2 = 20mfd, 220 volt. The total capacitance would be?
C = C1 x C2 / C1 + C2 NOTE: Resistors in Parallel = 15x20 / 15+20 C = C1 + C2 / C1 x C2 = 300 / 35 = 8.57
What does C.S.R stand for ?
Capacitor start capacitor run
What does C.S.I.R stand for ?
Capacitor start induction run
FLA
Full Load Amps (on an open motor)
The current in the run winding always _____ the current in the start winding because
LAGS - bc of the higher XL on run than start winding
The marked terminal of a run capacitor is connected to the _____ as the terminal is closest to the _______ of the capacitor
Line and Shell
LRA
Locked Rotor Amps (4-6 times of the FLA/RLA)
What type of motor would you use for a cap tube metering device?
Permanent Split Capacitor (PSC) ***min. cycle time 3min
What is the purpose of the bleed resistor on a start capacitor when used with a potential relay?
Protect the contacts in the potential relay from arching
RLA
Rated Load Amps (on compressor) -basically the same as FLA
How would you reverse the rotation of a split phase motor?
Reverse the wires on the start winding
The run capacitor of a PSC motor is always connected in _________ with the start winding and in ___________ with the run winding
Series and Parallel
List 5 Motors and their starting torque
Shaded Pole (40-50%) Split Phase (100%) Permanent Split Capacitor (50-80%) Capacitor Start Induction Run (up to 300%) Capacitor Start Capacitor Run (up to 300%)
In a split phase or PSC motor which of the windings has the highest resistance?
Start Winding
What does PSC stand for ?
permanent split capacitor
