Problem with Wadkin Cross Cut Saw

[seasonalbiz]

Hi all.

Ive got an old beast of a Wadkin cross cut saw... I guess its from around 60's/70's.

It periodically plays up in the winter, just takes a bit of fiddling with the start/stop and off it goes. This year its all but packed up, the blade turns very slowly... backwards! when its turned on.

I've had a sparky check out the electrics and he says there is no problem with the supply... or any dangerous issues within. Just wondering if anyone might have any experience of these old machines and encountered a similar problem.

Cheers.

(I did try and post a pic, but I can't as Im a newb... can't find any model number on the chassis - item 130832556478 on ebay is the same build format, albeit a bit older looking than mine)

 

[dickm]

Hi all.

It periodically plays up in the winter, just takes a bit of fiddling with the start/stop and off it goes. This year its all but packed up, the blade turns very slowly... backwards! when its turned on.

Assuming it's single phase, that sounds like a classic case of start capacitor failur.

 

[CHJ]

Is it an induction motor (brushless).
If so suspect the starting capacitor and or starting circuit.

See this PDF by Bob Minchin for all you need to know about induction motor wiring.

 

[seasonalbiz]

Thanks for your responses.

Its three phase... I guess the motor's in the region of 6hp - pretty hefty.

Not sure if its induction, I was planning to take the cover off the motor tomorrow for a visual inspection - dust build up etc.

 

[Chrispy]

My first thoughts are with the switch/contactor from experience thats the bit that wares out and you say you have had to fiddle with that as well, so i'd look at and clean the contacts, as it sounds as if its trying to run on just two phases.

 

[CHJ]

OK, ignore the comments about start capacitor and circuits.

3 phase is induction motor by the way.

Sounds like you have lost one of the three phase feeds to the motor, either wiring or switch gear.

Failing that then the motor windings are suspect and one of them is open circuit.
Your sparky should be able to check those two scenarios out quite quickly.


Make sure machine is isolated from supplies whenever you gain access to the wiring. Disconnected, don't rely on a switch.

 

[Peter Sefton]

+1 I had an old three phase saw bench many moons ago which was on a go slow and one phase had drpopped out.