220v circuit or motor problem

[shawnn]

I just got the power on in my shop and installed a 30a/220v circuit for my table saw. It's a dedicated circuit, single run of 10-2 romex 40' from the panel to a L6-30 receptacle. I have 110v on each leg but the motor will not run. I took the motor to a motor shop twice, he cleaned the start contact switches but says there's nothing wrong with the motor.

I worked my way back from the saw, wiring the motor directly at each junction until I connected the motor directly to the breaker with a short piece of SO cable and it ran. This made me think I had a break somewhere in the romex so I bought more. Before running the new romex I wired it directly to the breaker like I did with the SO cable, and it will not run. So, it will not run on either 45' piece of romex but it will run on the 8' piece of cable. Any ideas?

 

[pattenp]

First thing is you check voltage on 240V circuits by measuring the voltage across the two hots. Having 120V on the two hots independently doesn't mean you have 240V. The two 120V hots may be on the same side of the phase which will give you 0V. Have you manually spun the motor shaft to see if it will start up when hooked up to the 40ft of wire? You may be suffering from voltage drop and the motor is not spinning up on its own. Or, you are just getting the wires crossed when hooking it up to the romex.

 

[larry_g]

First thing is you check voltage on 240V circuits by measuring the voltage across the two hots. Having 120V on the two hots independently doesn't mean you have 240V. The two 120V hots may be on the same side of the phase which will give you 0V. Have you manually spun the motor shaft to see if it will start up when hooked up to the 40ft of wire? You may be suffering from voltage drop and the motor is not spinning up on its own. Or, you are just getting the wires crossed when hooking it up to the romex.

Measure the voltage across the two connection points in the breaker box, should = 240v If not then your on the same lge with both circuti breakers. Make sure you have a 240 volt breaker and not a split breaker with 2 handles.

If you have 240 volts in the wire in the breaker box then check the other end at the receptacle. If 240 at the breakerbox and not at the recp. then you have a bad wire.

lg
no neat sig line

 

[shawnn]

Thanks guys. I had the breaker contacts on a single bus rather than both buses. GE Powermark Gold isn't idiot-proof enough!