Warco WM-16 Motor Speed Fluctuation.

One common factor throughout the time I've been a member here is the poor reliability of these DC motor speed controllers. They are badly designed and made down to a price. I think personally it would be best to junk the controller and replace it with a genuine KB Electronics one or similar - or perhaps replace the motor with one of these nice brushless sewing machine motors and controllers.

I had a similar problem and it was caused by the new brushes, I would advise you to file the ends of the brushes until they are solid, get rid of the slitting and marking and make the ends curved to fit the commutator and they slide easily in their holders

To round the ends of the brushes make up a round bar the same dia as the com cover with a strip of wet or dry and spin it. Offer the brush to it true and square, job done. Noel.

There must have been hundreds of posts about failures of these boards. With the talent we have out there (not me) it must be possible to design a bomb proof board that could even withstand bring short circuited. Mount it in a metal box with a very low wattage heater. It would be a bit more expensive than the original, but buying one which then lasts for ever is cheaper than replacing the cheap, despite what the accountants will tell you

your statement is very misleading, there reliability is NOT poor, who knows what users do to them, but I can assure you that bmany thousands of users have no problem with their boards. I have had my lathe now for more than 10 years with no problems despite multiple stall occations.

Remember you ONLY hear about the ones that break, there are far more that don't.

No! they are noit badly designed, yes! they are built to a price as is everything.

I am sure Ketan at Arceuro would have some figures to hand regarding replacedment boards.

Crass cover all statements do not help when someone new to the hobby wants to buy a lathe as they will be worrying unneccessarily about reliability.

Hi everyone,

Thanks for the latest replies.

Noel, I fitted new brushes some time back but unfortunately it wasn't the issue. I tried redoing the brush ends too. At work I usually use a half-round file with a bit of emery.

The board I have is from KB electronics.

Another thing I can check is the contactor contacts. I know these can arc over time and eventually fail. I'll report back with the findings.

Ed.

Has anyone suggested freezing spray? Described here in detail. Intermittent faults are pigs to find because they're often due to micro-cracks in tracks or solder joints, or to poor contacts inside plugs and sockets. They open and close as the board heats up and cools, so testing with a meter doesn't find them.

The spray is applied area by area around the board. It isolates the problem by causing bad joints to contract and misbehave when the cold hits them. Once the general area is found, a close inspection usually reveals a cracked track, dry-joint, damaged component, or bad connection.

Dave