On Sat, 02 Feb 2008 18:23:05 -0500, Fred warydragon--at--gmail.com
wrote:

My Clausing 12x37 clone will not run backwards

Today, my Clausing 12x37 clone metal lathe has stopped turning off with the lever switch on the apron. I can switch
from forward to neutral to reverse and hear relays at the front lever switch work each time but it keeps running
forward. If I want to stop it I have to hit the emergency button. This is at least aggravating. But, I can get stuff
done as long as I don't need it to run backwards.

My problem right now is I'm all set up to run backwards for a threading operation that I don't feel comfortable running
forward. The lathe will only go forward and starts right up with the apron lever in the neutral position when the start
button is pressed. It still will not start in the forward and reverse apron lever position, as it's not supposed to.
But if it's in the apron neutral position it will start running forward when the start button is pushed. Cutting power
to the lathe does not effect this behavior when reconnected.

There are several multi wire relays in the panel box on the back and I suspect one of them is the problem, or the switch
in the front controlled by the apron lever. The motor is 220 single phase.

It has happened before and not really been a problem. The next time I used it it would act normally for a while. And,
maybe I can let the thing cool down and get these threads cut later tonight or tomorrow. But, I need to eventually fix
the problem.

I do not know how to diagnose how to fix this. Any suggestions on what I should do?

Thanks,

Fred
Take a look at your "inching button" it could well be stuck in or have
welded contacts. The "Heating Relay" comprises a set of resistance
wire single layer coils wrapped around bi-metallic strips. These wires
carry the motor current which if excessive will cause heating and
therefore bending of the bi-metallic strip. The bending action on any
or all of the strips opens a contact which will cause the main
contactor to drop out (FR contact in the KM1 coil line)

--

Richard

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