My dead 20 yr old Weatherking furnace blower motor is a 1/2 hp four speed, 1075 rpm Westinghouse. Brown and white wires go to capacitor, with yellow (med low) and black (high) connected, and blue and red capped off. Motor schematic shows white and yellow as line wires. Proposed new motor (AO Smith) is a three speed. Brown and brown with tracer go to capacitor, with wire schematic for black (high), blue (med) and red (low) - all show as line - and yellow as line. Can I make this proposed motor work so that I still have a high and a low (or medium) speed? It appears to me that the original had four wires connected, but the new needs five. Also, the proposed new capacitor to go with the new motor isn't marked with a red dot on one terminal like the old one was.

Follow the wiring diagram on the motor OR this. See bottom for PSC motors.

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Originally Posted by hvac1000

Follow the wiring diagram on the motor OR this. See bottom for PSC motors.

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Thanks for the schematics.
I still have some confusion as to where each of the wires on the new motor connects. The old one had four connected (two speeds not used) plus the ground, the new has what appears to be five (plus ground) - two to capacitor, two for the speeds that I want, and one more as a separate line. The original had one of the capacitor wires as line (according to the motor schematic), whereas the new one has a separate line wire which does not go to the capacitor (according to the motor schematic). Where would this yellow wire connect? Is this new motor possibly for a dual stage furnace where the motor speeds are maybe determined by the number of burners used at a given time? I'm just guessing. The fact that the schematics (from the new motor and the ones you furnished) show one line wire going into the three different speeds makes me think that is the case. I don't want to purchase the new motor until I am absolutely sure where each wire connects. Something just doesn't seem right. :confused:

It could be that not all the wires on the new motor are used.

You never mentioned the voltage of the motor you are working with?
You never mentioned the exact model of the motor you are working with?

This is not brain surgery. All you have to do is pick the speeds you want hook up the capacitor and attach the hot leed and neutral if 120 volt OR hookup both hot leeds for 240 volt operation. Also do not forget to ground the motor if a green ground wire is attached to the motor since it will usually have a round connector on it for the screw. You can attach it directly to the blower housing.

Quote:

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Originally Posted by hvac1000

It could be that not all the wires on the new motor are used.

You never mentioned the voltage of the motor you are working with?
You never mentioned the exact model of the motor you are working with?

This is not brain surgery. All you have to do is pick the speeds you want hook up the capacitor and attach the hot leed and neutral if 120 volt OR hookup both hot leeds for 240 volt operation. Also do not forget to ground the motor if a green ground wire is attached to the motor since it will usually have a round connector on it for the screw. You can attach it directly to the blower housing.

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My system is 120 volts. You've given me plenty of info to go on. Thanks again.
:)