Seig sc3 'ticking over'?

My sc3 mini lathe has started trying to creep round when the speed pot is at zero.
Not really spinning, just trying to, and not all the time.
Anyone else found this?

Mine has done that a couple of times i think it may be a bit of dust in the pot switch or wear.

A poor connection can cause this. Check all cables are secure.

Martin C

An automatic gearbox in a car tries to creep at idle. Nothing unusual. These speed controllers are not absolute speed indicators and they are set up initially with some bias within the circuitry so that they actually come to rest at a greater reading than zero on the indicating knob. I expect most do that.

Yours is on the borderline, I expect. An electronics type would likely easily trim a pot on the circuit to correct this tendency.

Happens on my SX2P mill occasionally which is of course exactly the same electronics. I find that isolating the supply usually cures it.

Martin

If you are turning the pot to zero rather than stopping the machine I would have thought this would be a risky practice, taking a measurement or using a chuck key should surely not be done unless the machine is properly stopped, the spindle is live even if the pot is set to zero, any disturbance could cause the spindle to move which could be painful.

Mike

The speed pot should have a built in on/off switch. I think there's a preset on the board for minimum speed BUT I would advise a bit of switch cleaner in the pot first.

My mini mill spindle occasionally creeps so I stop it with the red emergency stop button to change tools. Colin

Edited By colin hawes on 01/02/2018 18:45:51

My C2 does the same occasionally. I try to switch the lathe of or set the direction in neutral before I use the chuck key. But I often forget. Never caused a problem though. I think there wouldn't be much power in the creeping chuck.

Thanks everyone, puts my mind at rest.
I always hit the stop switch before handing the work or chuck.
I shall get a sparky mate to check it over.

Can you confirm which version of the C3 you have?

The earlier C3 has a brushed motor, the control board of which has a min speed adjustment, the later brushless version doesnt appear to have any 'user' adjustable tweaky things...( I've had both machines...)

Maybe Ketan can assist us with any technical adjustments  ?

Edited By John Rudd on 01/02/2018 18:56:52

That's a seriously deficient design. Stop should unconditionally mean stop by the removal of supply. A restart should not be possible by the action of just resetting the stop switch.

If the machine had been stopped by the use of a stop button I would agree with you, but turning a speed pot to zero is little different than using a lathe with a mechanical clutch which leaves the motor running and the spindle stopped.