Dual voltage single phase motor troubleshooting

[jwmay]

I've got a dual voltage single phase motor I'm really trying to will back to life here. I thought the motor leads were damaged but they aren't. It all looks fine.
I'm used to three phase motors, but don't know what I'm doing with this. The internet didn't yield anything I didn't know.
The motor doesn't smell burnt, but it's been out of service for many years. Perhaps the smell fades. Meter between L1 and "L2?" reads resistance long enough for the meter to beep, but then the tone stops and the meter reads OL. Meter between windings reads resistance, although I just realized I didn't see what it was. I just listened for continuity and moved on.
If I plug it in through a 15 amp breaker, the breaker trips immediately as soon as I flip the switch. If I go around the breaker, the motor makes a noise...kind of a hum, and the amp clamp got to 13.9 amps before I shut it down.
I think I'm being clear here, but you tell me. FLA is 8.6 for 120 volts, so 13 at start up didn't seem unreasonable to me. But the spindle didn't even jump. I guess a cap would be cheap enough to try before I abandon all hope. Any thoughts?

 

[woodchucker]

13 is not unusual for a start. I have a tablesaw that is 1.5 hp, on a 20amp breaker it occasionally pops.. I checked and inrush can be 63amps on startup.
I'm betting you don't have the motor and mains married at the same voltage. one is 220, and one is 115... just a hunch. if you think the cap is bad, try rotating the motor during startup... just roll it and then turn it on.
I just rebuilt a grinder and did that after I let the smoke out of the cap. I didn't know that the centrifugal switch didn't release because I preloaded it too much. Anyway, I took the cap out of the ckt and would rotate it to start it, to make sure the new bearings were good before putting more money into it for a new cap.

 

[jwmay]

I'm betting you don't have the motor and mains married at the same voltage. one is 220, and one is 115... just a hunch.

It's possible, but I think it's right. I haven't changed the way it was wired when I got it. It was just missing the plug. I'll double check the wiring diagram in the manual, but that was how I determined which voltage it should be. According to the diagram ( or my understanding of it), it was wired for 115, so that's the plug I put on it. Anyhow it never hurts to reverify. Thanks!

 

[jwmay]

Now I did skip the drum switch too. Probably should have said that. Maybe these dual voltage motors aren't as simple as a black and a white wire to start the motor?

 

[markba633csi]

If you're tripping the breaker on power up it's not the cap- you have a short somewhere, or a miswire
Post some pictures of that bad boy, we might be able to rescue it
-Mark

 

[jwmay]

I'll get pictures tomorrow morning for you. Today I just have the diagram out of the manual and my notes from when I opened it up. The chordset was damaged and has to be replaced. I don't know what's happening inside the drum switch as the manual shows. But I'm thinking I caused the problem by trying to wire direct. There has to be a reason the orange and red leads go back to the drum switch.

 

[jwmay]

Well never mind. This motor is fine. As I said earlier, I wasn't certain of the circuit closures happening in the drum switch. I opened it up and did some continuity testing with the switch in forward, reverse, and neutral and it all made more sense. The motor runs pretty smooth at 6.6 amps on 120. And the spindle brake works too. So...crisis averted.
The whole thing was my fault by trying to take a shortcut and skip the drum switch. It's doing something important here! Lol Thanks for the support fellahs!
Of course, I'm not done because now it's all coming back apart to be rewired at 220. But at least I know the motor is ok. Whew!

 

[markba633csi]

OK good deal. Looks like T5 and T8 are probably the start leg and T1/T3 and T2/T4 are the main windings so changing it for 240v should be fairly easy
It's an unusual drum switch, must be old
-M

 

[jwmay]

It's an unusual drum switch, must be old

I think it's from the 60's? It's branded Furnas I believe. All sealed up, unlike the others I have seen. The operating lever looks like Bakelite, so I imagine there will be a day when it breaks off. The wiring diagrams in the manual are very good. I need to check if the overload contactor is wired differently for 240 also. Putting it here may help me follow through. I already have a little devil on my shoulder saying "come on man! It works as is! Just use it already. You don't NEED to rewire it again!" Lol

 

[markba633csi]

It's not drawing much current on 120, I wouldn't rewire it