Turning on Hold

On Tue, 10 Jan 2012 10:09:20 -0600, James wrote (in message ):

Did the motor make a loud humming/buzzing noise? Is the motor a single speed motor? If yes to both of these questions, it is likely the case that you have a split-phase motor. That is, it is an induction motor with starting windings and an internal centrifugal switch that opens the circuit to the starting windings once the motor gets up to about 70% of its normal speed. The starting windings are a *relatively* high resistance, compared to the main running windings, and the capacitor is used as part of the starting winding circuit to provide a much higher starting torque. When the motor seemed to work with a new capacitor - and then did not start again after the capacitor burned out, suggests to me a partially shorted coil in one of the starting windings. This would cause a very high starting current and a much diminished starting torque - even with the capacitor. The high currents burned out the capacitor. If this is the case the only remedy for this motor is rewinding the starting coils, a prohibitively high expense in this day of automated coil winding in new motor manufacture. (I did some of this kind of work in trade school 45+ years ago.) A fresh motor is indeed called for. When you get the new motor, if it is a split phase motor, have your local shop install a

4-way switch on the starting windings, so your motor will be reversible. If they say it can't be done, go to a new shop or contact me for instructions. tom koehler

tom koehler wrote in news: snipped-for-privacy@news.frontiernet.net:

It's off of a Jet JWL 1236. Here'e the spec's on the motor TEFC, 3/4HP,

1PH, 115V Only, 60Hz, 8A, 1720 RPM What's the advantage of reversible? The shop I used has been in business forever and knows what they're doing. I also use another one who has bee around a long time.When I get the new motor I'll look into it. Jim

On Tue, 10 Jan 2012 16:38:29 -0600, James wrote (in message ):

Yeah - you have a split phase motor. A reversible lathe allows convenient sanding in both directions - more gooder (that's a technical term) than just sanding in one direction. With a split phase motor, you stop the motor and let it coast down to a stop, then reverse it and restart. Got to allow the centrifugal switch to reset. tom koehler

if you are willing to do so, you will be well served by replacing that jet motor with an older washing machine motor - they can be had for $5 or so, are about 1/3 to 1/2 hp and will serve you better - but they are bigger (real horses, not smaller Jet horses) so typically you will need to make a bracket and use a longer belt. You could even get a real 3/4 hp motor for about $50 (new surplus) if you wanted it. I use a 1/4 hp washing machine motor on my Nova Commet and it is just fine.

I pretty much have to stick to the Jet motor because of the design of this model but I will look into a reversing switch. Jim

There was an article in either the Dec or Oct issue of American Woodturner (AAW journal) on installing a reversing switch IIRC. Looked pretty straight forward...

...Kevin

.>> I pretty much have to stick to the Jet motor because of the design of

Old Chief Lynn

Mine is reversible, and at usually slow sanding speeds the chuck has never come off. If you want to actually turn in reverse, the last two Nova chuck inserts I bought have a set screw that is located so that it impacts the shaft past the threads.

I seldom use the set screw since the time I forgot to loosen it and tried to take the chuck off. Little file work on the first thread fixed that mistake.

Just get in the habit of turning the speed down before reversing. Then slowly bringing the speed back up. Usually my chucks are on really tight so don't spin off, but sometimes they do. I usually have a tailstock up when that happens though so the piece can't really go anywhere.

After you've had reverse for a while you'll wonder how you ever got on w/o it...

...Kevin

At the motor shop - do they re-wind and re-build old motors ?

IF so - have it fixed.

Mart>