Turning on Hold

[James]

Hi Group, I've got to put my turning on hold. I just lost the motor on
my Jet lathe. It had a problem when I bought it you had to spin it to
start it so I took it in to have it looked at and had a new capicitor
put on. When I was using it yesterday it quit so I took it back to the
electric shop and they replaced the capicitor again and run the tests
on it again. It worked fine for a minute then tripped their breaker.
It's got a fault in it somewhere that's probably why the capacitor was
disconnected and it had to be spin started. Fortunately a new motor
isn't too pricey if you say it fast. If I had know for sure the motor
was bad I would have put the cost of the repair toward a new motor but
even with a new motor the lathe was still much cheaper than a new one.
Jim in ID
--

[tom koehler]

On Tue, 10 Jan 2012 10:09:20 -0600, James wrote
(in message <SZydnc4UhcYt_5HS...@earthlink.com>):

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

--
I will find a way or make one.

[James]

tom koehler <tvnospa...@nospamfrontiernet.netinvalid> wrote in
news:0001HW.CB320CF3...@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

[tom koehler]

On Tue, 10 Jan 2012 16:38:29 -0600, James wrote
(in message <Xns9FD69F1FB177Fba...@94.75.214.39>):

> tom koehler <tvnospa...@nospamfrontiernet.netinvalid> wrote in
> news:0001HW.CB320CF3...@news.frontiernet.net:
>
>> On Tue, 10 Jan 2012 10:09:20 -0600, James wrote
>> (in message <SZydnc4UhcYt_5HS...@earthlink.com>):

>> 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
>>
>
> 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

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.

[Bill]

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.

[James]

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

--

[Kevin Miller]

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
--
Kevin Miller
Juneau, Alaska
http://www.alaska.net/~atftb
"In the history of the world, no one has ever washed a rented car."
- Lawrence Summers

[coffelt2]

.>> 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
> --
> Kevin Miller
> Juneau, Alaska
> http://www.alaska.net/~atftb
> "In the history of the world, no one has ever washed a rented car."
> - Lawrence Summers

OK, I'm pretty dense here, I can appreciate the concept of sanding
with the work turning in reverse, but in my case, the chuck is apt
to spin off the spindle and shoot out the door, carrying my nearly
finished art work with it. I give you that it might be easier to find my
shiny Nova chuck out in the weeds and blackberry bramble, but the
rusty old Grizzly might be lost forever. Stronger door?

Old Chief Lynn

[Gerald Ross]

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.

--
Gerald Ross

I'm so poor I can't even pay attention.

[Kevin Miller]

On 01/11/2012 09:12 PM, coffelt2 wrote:
> .>> 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

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...

[Martin Eastburn]

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

IF so - have it fixed.

Martin