Small AC motor connections?

Try this:

One 240v leg to Black Other 240v leg to Red and one terminal of the cap Other terminal of the cap to Yellow

To reverse the motor's rotation

One 240v leg to Black Other 240v leg to Yellow and one terminal of the cap Other terminal of the cap to Red

I've run into this on several single phase motors, and it usually works.


Reply to
John Holbrook
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I have a GEC type BCP 1508 B, 75W 240V 1ph AC motor that I want to use and dont' know the correct connections. Years ago I was told but have subsequently lost the information. I have a 5uf motor run cap which was recommended for it. The motor has 3 wires red, black and yellow. Does anyone know the correct wiring for this, I haven't found anythig on the web.


Reply to
David Billington

What John said. It would appear that the motor is a PSC permanent split capacitor type motor. A good way to confirm that it is, would be to use an ohm meter to check the motor's windings resistances (with no power connected, of course, and without the capacitor connected).


(Case) to earth ground (usually a green or green/yellow lead)

The windings in a PC motor are identical and connected as 2 in series, and should be nearly the same resistance reading. This will depend upon the quality and type of ohm meter that's used, and the condition of the motor. The readings would normally be relative to two readings that equal a doubled value when added (two 10 ohm windings equal 20 ohms in series, for example). For those familiar with transformer windings, the PC motor will check like a center-tapped transformer winding. Significant differences in normally equal resistance readings indicate that the motor is not the PSC type design, or has an internal fault condition (assuming that the ohm meter is operating properly, used properly and it's operation is understood by the user).

The check should also include a ground check for continuity from the windings to the motor case. The readings to the case should be infinite (open, no continuity) or very high megohms (if you don't have your fingertips on the probe tips, which is a bad practice).

Note that an ohm meter *check* is not conclusive that the motor's insulation is good, since the meter's test voltage is very low compared to a motor's actual operating voltage. A low ohms reading from the winding leads to the case indicates that there is a winding-to-case short, and the motor will fail to operate properly (if at all), and also presents a shock/electrocution hazard.

WB .................

Reply to
Wild Bill

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