GH 1330 Starter capacitor problem?

Hi Folks, I have a Warco GH 1330 that has worked well since new 9 years ago but last night it wouldn't start forwards but would start in reverse. Leaving it for 10 minutes (presumably allowing it to cool) then allows it to restart forwards and it will then operate properly for perhaps 10 minutes before again refusing to start forwards.

In other applications this sounds like a capacitor starting to break down but I cannot get my head around its willingness to start in reverse when it won't start forwards.

Does anyone have any experience of this type of event that may shed some light on this?

Thanks in anticipation of some useful knowledge.

Colin

I had a similar problem on my gh1330 turned out to be a bad solder joint on the centrifugal switch in the motor

Ahaa, Thanks, that answers the next question of whether the motor has a centrifugal switch. How easy is it to access the switch?

Thanks

Colin

Hi Colin,
Like the start capacitor the centrifugal switch would normally effect both forward and reverse if it was faulty.
I would suspect the reversing switch but why it should start to work again after a time as is strange as it would not normally get warm.

Les.

My chester 626 mill motor did exactly this last year and it was a worn out, ( cheap crap to start with) reversing switch. About £1.75 from Maplins. Suspect lathe reversing switch is not a simple rocker though.

Rick

Colin, if you are going to investigate the centrifugal switch, its a motor on the bench job, then simply pull off the motor end cap, if memory serves correct the switch is at the output shaft end of the motor.

Thinking deeper into this, it could be one of the motor contactor's causing the problem, I would certain!y check this out first before pulling the motor.

Hi Colin,
You could check the operation of the centrifugal switch by connecting multimeter set to a low ohms range to the centrifugal switch terminals. (Or a battery and a bulb.) with the motor stopped the switch should be closed. If yo can then spin the motor with an electric drill up to near its rated speed the contacts should open. You could try rotating it in both directions as a further test.

Les.

Thanks for all of the suggestions, they all have merit. I think I'll begin with checking out the reversing switch as it seems the logical culprit, does anyone know where it resides? I can't see any reference to it in the parts book?

And with regard to checking out the centrifugal switch, I'd need to identify the appropriate terminals first. The wiring diagram isn't exactly clear, at least to me!

Cheers

Colin

Hello Colin and others. Once you have the motor off the machine why not run it on the bench forward and reverse, that would eliminate the motor.I'm not familiar with your motor or lathe but most of the chinese motors have their centrifugal switch at the shaft end. and are held together with three screws or botls so no problem with re assembly.I think yours will be cap start and cap run. If you have a digital camera take plenty of pictures and mark all wires and their original position/terminal. I have taken apart Axminster motors and seem to think they have an unusual centrifugal switch, could be wrong. One of the motors I fixed had a faulty start capacitor about 70 micro farad,not critical,well thought out and nicely made. I dis-like the advert and comments regarding Chinese motors in the Model Engineer magazine.Ted

A good many of the motors on Chinese machines have a centrifugal switch that can be got at without removal of the motor, there is a disc of sheet metal on the end opposite the pulley, undo 3 or 4 screws, and there it is, had a little trouble with it fouling the motor frame, and blowing fuses, a bit of a bend. and some insulation about 20 years ago, and it has not missed a beat since. Ian S C

I believe that I've found the problem. First of all I found the reversing switch, hidden on the RH end of the bed, in its own little housing. As it's only about 9" away from the wall on the RHS I've never had cause to look at that view of the lathe since it was planted and hadn't noticed the switch location.

Anyway, the switch mounting screws had become loose with the lower one completely out of its thread in the back of the housing, causing the switch to pivot on the top screw and move away from the "forwards" actuating cam. Because the upper screw was still, mostly, in place, it served to hold the switch sufficiently for the "reverse" cam to actuate the switch. Why it would appear to work in forward after a rest period I don't know.

Sadly, only the upper screw will hold and the lower one won't tighten, so I'll have to deal with that but at least the lathe now seems to work OK in both directions but I'll do some work on it tonight and see how it performs. Also, now that I'm listening for it, the centrifugal switch can be heard operating properly (in both directions) as the chuck slows down to stop.

Thanks to all who contributed and participated in this discussion, you've been a great help to me and I've learnt a few things from it.

Cheers

Colin