I am rewiring a 1725 rpm, single phase 1/3 hp AC GE Industrial motor Model 5KH39QN9397C. It has four wires: red, black, yellow and green. Label on motor states that line voltage is red-black and green is ground but does not mention the yellow wire. Resistance between the wires is red-black = 4.8 ohms; yellow-black =3.1 ohms; yellow-red = 2.2 ohms. What is the role of the yellow wire? Will connecting the red and black to line voltage cause the motor to run @ 1725 rpm? Will connecting line voltage to red and yellow or black and yellow cause the motor to run at a different speed?
Electrical – Role of yellow wire in 115v AC Industrial motor
induction motor
Related Solutions
With the given information and discussion, I think the motor will operate with the following connection. The capacitor may not be needed. It the current in the start coil can be measured during start and it is relatively low with a capacitance value used for similar Hp motors, it might make sense to try a direct connection from the switch to the power line. There would be a risk of burning out the winding fairly quickly if it is designed for use with a capacitor.
Various electrical diagrams for washing machine are available on the internet. Some show motors that use a start winding with no capacitor and some show a capacitor. The extra centrifugal switch is shown on some as switching a function external to the motor. The extra contact on the starting centrifugal switch is shown as feeding power to an external function when the motor is up to speed.
If the centrifugal switch is OPEN when at rest, that's your problem. It should be CLOSED at rest and OPEN when at 80% speed.
When you stall and try to keep using a single phase capacitor-start motor, it slows down, then the centrifugal switch re-closes, putting the start winding and cap back into the circuit. But that winding is not designed to be used under load, neither is the centrifugal switch. You burned out the switch, maybe the winding insulation too.
Best Answer
It is a split phase motor, but there is no capacitor in a split phase motor design. CSCR (Capacitor Start - Capacitor Run) or CSIR (Cap start-Induction Run), yes. But a Split Phase is used specifically BECAUSE it doesn't need a capacitor to make it turn the correct direction.
Here is the wiring diagram. You don't touch the yellow wire (or the blue for that matter). https://www.grainger.com/ec/pdf/6XH45_2.pdf
You can change the direction of the motor, you cannot change the speed.