220v aircompressor

[randy_68]

I am new to this forum and I need help. I just installed a 220v 1 phase air compressor in my shop and it won't run. I installed a 20 amp breaker in my box and ran 10/3wg (red and black to hot and white to ground, neutral not used) and hard wired the compressor switch. The switch is prewired to the motor with black & white hot and green ground. I connected black to black, red to white and my white to ground at the switch. I tested the terminals inside the back of the motor and have 120v at each terminal but the motor will not come on. After this I thought the motor was bad and Rural King replaced my motor but it still does not work.I also tried bypassing the comp switch but it didn't change anything. Could I have 2 bad motors? Any suggestion? Thanks

[Snoonyb]

You probably have the wrong style breaker.

The breaker you need will occupy 2 breaker slots.
If you have any open breaker spaces, you'll notice that there are two separate buss bars.
The potential available at each is 180 degrees out of phase from the other.
A meter attached to each and ground will result in a reading of 120V, however, when placed between them, will read 240V.

[HayZee518]

You said you ran 10/3 - you don't need 10/3. 10/2 would be sufficient. On a two pole breaker you connect a black and a white taped with black tape. the equipment ground [the bare wire] connects to the green screw in your equipment and to the neutral bar or aux bar [if your have a sub-panel]
220 will be available at the compressor.

[randy_68]

Thanks for the info. I did have a 2 pole breaker installed. Iwent over everything last night and I got it working. I diconnected the 2 pole breaker and ran each hot wire to 2 seperate 110 breakers just to see if that was the problem and it worked. I guess the breaker is bad (it was used - it came with the box which was used) so I am picking up a new breaker today.