Jet mini lathe hot motor

what kind of circuit is the lathe running on? I've had problems with motors running on either extension cords that are too long or electrical circuits that have many other devices installed.

PS H> I just bought a Jet mini lath with the nova chuck on sale at

I spent two days working on a jet mini lathe last year. The motor got hot, but not too hot to hold your hand on it.

MH

If the electrical input is good, than take off the belt and spin the motor and also the spindle by hand, they should run freely, if not find out why, like the spindle might be tightened to much, if all checks out ok, I would go back to the seller with it and get a new one.

Fred wrote:

I got one of the "bad" motors a few years ago and had it changed under warranty... My assumption was that it went out because IMHO it ran too hot.. but the new one has run just as hot and has been going for 6 or 7 months now..

Mac

My jet motor runs 'too' hot but it is still running after 2 years. fwiw

I just set up my shop in my basement and wired a separate circuit for each tool and work station. Most are 20 amp except for the larger tools.

The spindle shaft and the motor will spin freely without the belt on the Jet mini lathe.

I just let the little lathe run for 20 minutes without any load and still too hot to touch the motor. Maybe thats ok. None of my other motors run that hot even under load.

I do like the little lathe.

Thanks for the help.

Fred

Fred wrote:

Hi Fred, If the lightly built motor is still too hot to touch after you have checked all the obvious causes, it's likely running hot enough to burn out soon. Even if not, you will probably worry if it will and not enjoy your lathe as much as you should. If it's not too much trouble to return etc. I think you have every right to exchange it and you would be much happier doing so.

Just butting in, as usual. :)

Turn to Safety, Arch Fortiter

"Arch" wrote: Hi Fred, If the lightly built motor is still too hot to touch after you have checked all the obvious causes, it's likely running hot enough to burn out soon. (clip) ^^^^^^^^^^^^^^^^^^^^ Arch is right. It could continue to run hot and then burn out when the warranty has expired. I would talk to Woodcraft about it, and at least get it on record. I also suggest calling Jet. They may surprise you and authorize an exchange, or a new motor.

This topic of the mini-lathe motors running hot was covered in the past on one of the turning groups. I could not remember which one. I can barely remember the conclusion of the discussion. It probably had something to do with electrical theory, which I am not strong on. It seems to me that everyone who responded had experienced the hot motor problem. I have a King clone of the General "Maxi Lathe" and it's motor is pretty hot after several hours of turning. I keep the wood chips from building up around the motor and blocking the air flow. "

Are you sure the belt tension isn't too tight? I'm thinking this could cause some hot motor and headstock conditions. Do you remember if the headstock where the spindle protrudes was very hot too?

With my Delta midi/mini, I just push the motor down to the point of just feeling tension on the belt and then tighten the lock bolt.

Hi Fred,

I too have one of the Jet Mini's that runs hot. It has always run hot although it was fine for a couple years and I never though much about it until the capacitor burned up.

I replaced the capacitor with a new one from Jet and its been running for a couple more years but still too hot to touch. It doesn't seem to matter if it runs with a load or not, with an extension cord or as the only thing on a 20 amp circuit, or any of the other suggestions I've heard. I only use if for small turnings and I'm not aggressive with it. And I keep an air hose at hand to blow the shavings away when they build up but it just plain runs hot.

It gets hot in a few minutes but remains at about the same temperature even when I run it almost non-stop for 6 to 8 hours or more. I expect it to quit anytime and if I could return it and try another I think I would.

Bertie

Fred its a question of how Hot is Hot? all Motors are rated with an Insulation Class which relates to the Maximum Running Temperature before the Insulation begins to break down and eventually cause a Motor Burnout.

Somewhere on the Motor Plate it should indicate the Motor Insulation Rating?

Class Y is the lowest and Max. Temperature = 90°C [194°F] A = 105°C [221°F] E = 120°C [248°F] B = 130°C [266°F] F = 150°C [302°F]

There are more but Temperatures are much higher for really large Motors for Industrial Use.

Remember these are the Temperature in the Windings so there will be a slight loss if you measure just the outside casing of the Motor.

If you can establish the Insulation Class and measure the Temperature, even if it is only the Motor Casing, you should know whether you are in the Danger Zone.

Wow, even the lowest is too hot to touch - even if there's a 50F difference between the windings and the case.

My Jet mini motor has 60degC stamped on the motor. I can't get a thermometer until tomorrow but I think my motor is running a bit hotter than that. I will see what the outside temp of the motor is tomorrow and report back.

Thanks.

Owen Lowe wrote:

Fred it is unusual to have a Motor marked like this? a bit of Googling came up with this:-

Such motors include those used on bench grinders, power saws and the like. For those applications, Underwriters Laboratories sets maximum acceptable surface temperatures for a metal "surface subject to casual contact" at 70° C(158° F) after 30 minutes of operation in a 25° C(77° F) room.

Perhaps they are trying to impress UL?

RVS