Ancient furnace motor won't start
 

I have an old furnace from what appears to be the 70's. The blower motor quit working. The motor was simply humming and very warm so I changed the motor out with a US Motors brand motor. The wiring schematic on the motor was less than stellar. In lieu of stating hot/black wire etc it said "ungrounded line". I took that to mean hot wire and hooked it up accordingly.

The new motor is doing the same thing (Simply humming.) Any ideas? It's 48 degrees in my house!

If it uses a run/start capacitor that may be the problem. Can you carefully start the motor spinning by hand?

You should have gotten a new capacitor with the new motor. If not, replace the old capacitor per the specs for the new motor.

It's my assumption that the capacitor is attached to the motor which I replaced. There is nothing beside the motor which mounts directly on top of the squirrel cage. Tomorrow I plan to check the current leading to the motor, and then check the motor itself by attaching a cut off heavy duty extention cord to it. Past that, I am out of ideas.

Rescue motors don't come with capacitors. You have to buy it seperatley it should say on the motor box what size cap the motor will need two brown wires

joechuckg; you are correct. It used to be that 99% of the replacement motors came with capacitors but, not to save on cost, they no longer include them with the motors. Can't tell you how many times I've recently purchased a new motor only to find out I forgot to order that cap with it.