Capacitor Wiring

[bowlweb]

Thanks in advance...

I replaced a 30 year old blower motor in a Rheem furnace recently. 1/2 HP Direct Drive with 7.5 x 370 capacitor.

Three wires run to the motor, one 115v from the fan limit to turn on low speed in heating mode. One 115v from the fan center to turn on high speed in cooling mode. The other is neutral.

One leg of the (original) capacitor was wired to a motor capacitor wire. The other leg was wired to the other motor capacitor wire and neutral. This neutral ran up into a junction box and was connected to the motor neutral and the furnace neutral.

I've never seen a capacitor with a neutral ran to it. I wired the new motor the same way. It ran, drew good amps.

Is this kosher, or should I run a constant 115v to the capacitor via a new wire? I don't see how the capacitor could do its duty this way.

Again, thanks.

[smokin68]

[QUOTE]Originally posted by bowlweb
Thanks in advance...

I replaced a 30 year old blower motor in a Rheem furnace recently. 1/2 HP Direct Drive with 7.5 x 370 capacitor.

Three wires run to the motor, one 115v from the fan limit to turn on low speed in heating mode. One 115v from the fan center to turn on high speed in cooling mode. The other is neutral.

One leg of the (original) capacitor was wired to a motor capacitor wire. The other leg was wired to the other motor capacitor wire and neutral. This neutral ran up into a junction box and was connected to the motor neutral and the furnace neutral.

I've never seen a capacitor with a neutral ran to it. I wired the new motor the same way. It ran, drew good amps.

Is this kosher, or should I run a constant 115v to the capacitor via a new wire? I don't see how the capacitor could do its duty this way.

Again, thanks. [/QUO

I usually work on 240v fan motors, but whenever I install a fan motor it gets a new capacitor,and the one that goes with the new motor, no matter how the old one was wired. I sure there's many different ways to wind a motor, as there are different types of capacitors (start,run ,psc)etc.

Yours is working so you must have done something right.

[bowlweb]

Thanks. The capacitor was new, too. The old capacitor was a 6x370. The motor is single phase 115v. Just thought it weird. I've done mostly residential for the last 10 years and have never seen that before - though this furnace DOES predate me.

[beenthere]

Get a motor out of your truck, and look at it.

The brown striped cap wire is the same as the common lead of the motor internally.

It should should you this on the diagram.