Motor trouble on Jet mini, anyone else?

[Perry Holbrook]

I've been turning for several hours on my Jet mini today. Late in the day I smelled a hot electrical odor. Once I turned it off, it wouldn't start without some hand spinning of the chuck. Then the smoke. I pulled the capacitor and it is cracked around the spade connections.

While I was turning, I tried to keep the chips off the top of the motor and out of the fan vent, but so there was some blockage at times.

I'll get a replacement capacitor Monday, but my question is has anyone else had a similiar problem and was this failure due to a lack of motor cooling. Seems like you're going to always have some chip on and around the motor. I was just wondering if this is normal and/or do I need to do some re-engineering?

Perry

[Bill Wyko]

No motor smoke but it's starting to growl and it has a knock now too. woodWorkers is going to take the mini back and put it towards my new lathe. Those guys are the best there.:D

[Bill Boehme]

I've been turning for several hours on my Jet mini today. Late in the day I smelled a hot electrical odor. Once I turned it off, it wouldn't start without some hand spinning of the chuck. Then the smoke. I pulled the capacitor and it is cracked around the spade connections.......
I'll get a replacement capacitor Monday, but my question is has anyone else had a similiar problem and was this failure due to a lack of motor cooling. Seems like you're going to always have some chip on and around the motor. I was just wondering if this is normal and/or do I need to do some re-engineering?

Perry

Capacitor failure is a fairly common problem on the Jet mini lathes and probably several of its clones. The main problem is that the capacitor used is a "start" capacitor and it ought to be a "start/run" capacitor which is much more heavy-duty. Matters are not helped by the fact that this particular motor runs very hot, which does not help the life of the capacitor. I suggest getting one of the oil-filled start/run capacitors designed for use on HVAC blower motors. They are sort of shaped like a prince Albert can and are too large to fit the form factor of the old capacitor, but that is actually a good thing because it will force you to mount it in a cooler location away from the motor such as on the inside of one of the legs at the headstock end of the lathe.

Hard turning for an extended period can cause the motor to get really hot. I suggest being less aggressive in cutting wood and give the lathe an occasional cooling off period.

Bill

[Jim Underwood]

I'm not sure exactly what capacitor they use on the Jet Mini, but Bill is correct, it is a common failure.

The reason I'm not sure what kind of capacitor they use on the mini, is that I bought a capacitor locally that looked just like the one I took off, and was rated the same, but it only lasted a few minutes before it spewed it's guts....

So I finally broke down and bought one from WMH Toolgroup.

If you buy the OEM part, be sure to call your order in to WMH, because they charge an arm and a leg for shipping online orders.

[Bill Boehme]

I don't recall the capacitance value offhand, but if you check the old capacitor to get the value and then go to Grainger's, you can get an oil-filled capacitor for somewhere between five and ten dollars. Even if you decide to go for the OEM part, it would be a good idea to mount it off the motor -- make certain that everything is properly insulated with no exposed connectors. With the oil filled types, you can get a rubber boot that covers the terminals.

Bill

[Perry Holbrook]

Thanks so much guys. I've got a motor rebuild shop near me and will now be able to discuss the options with them and know what I'm talking about.

Thanks again.

Perry

[Bruce Shiverdecker]

One thing I found out not too long ago, is that Most mini lathes use intermittant duty motors. They are to be run for about 20 - 30 minutes, then allowed to cool down. To stop the overheating, you need to replace the motor with a constant duty motor, or be sure to cycle the motor.

Bruce

[Perry Holbrook]

Just to update this, I replaced the capacitor with an oil filled one this morning and remote mounted it. I also put a shield on the bed to help keep shavings off the motor and will pay closer attention to keeping the fan intake clear. This should keep me going.

As I said in another current post about the mini, due to my slowness as a beginning turner and my backlog of orders, when I turn, it's pretty much an all day affair so I may be pushing the limits of any mini. But it fits my space and all my pieces are very small so the mini is a good fit. I think the Jet is a good machine.

Perry