The Dreaded X axis stepper error using UC400ETH and UCCNC !!!

[dachopper]

Ok , Thanks Clive / M_C

I ended up running a separate ground from the spindle all the way back to the star, and from the sleeve all the way back , and another from the inverter power feed all the way back

The shock I was getting on the Z axis has moved to a different area of the frame ..... WTF !


I don't really understand how AC voltage is detected, but what I noticed is that I seem to have 12 Volt AC between my machine and the workshop floor, although the freq jumps. When I power up the anxillary devices, ( water pumps, spindle powered but not turning, and woodchip extractor on but not turning, the A/C jumps up to a constant 105-110 Volts 60Hz. I get a tingle touching the machine frame bearfoot after that.

Does this seem like an earth leak in the shed somewhere?

The machine frame was earthed to the same star point as the inverter / Dc transformer / spindle / spindle sleeve. I tried discnnecting it as I'm trying to figure out where the zapping is coming from.

All I know is that with the machine on and the DC steppers motoring, there is no problem and no zapping.

With the spindle relay on..... and spindle turning there was big zapping when the spindle rotated.... that is fixed , but now there is a smaller underlying zap that is on when the A/C power is on regardless if the devices are turning or not.

Should my stepper motor power sleeves also go to the same A/C ground? they are currently not connected? ( insulated both ends )

[Clive S]

Ok First from what you have said are you sure that you have a good earth into your shop (is it actually connected)?

Where are the pictures?

It is beneficial to wire steppers with 4 core screened cable with the control box end of the screen connected to the star point.

Personally I would keep the vfd mains wiring on its own socket.
If you have grounded the screen on the spindle cable at the vfd end. then don't connect the screen at the other end.

Have you grounded the machine frame? to the star point. (the purpose of the star point is to avoid ground loops)

I take it that the electricity supplier give you an earth connection and that you are not using an earth rod in the ground.

[dachopper]

Ok First from what you have said are you sure that you have a good earth into your shop (is it actually connected)?

Where are the pictures?

It is beneficial to wire steppers with 4 core screened cable with the control box end of the screen connected to the star point.

Personally I would keep the vfd mains wiring on its own socket.
If you have grounded the screen on the spindle cable at the vfd end. then don't connect the screen at the other end.

Have you grounded the machine frame? to the star point. (the purpose of the star point is to avoid ground loops)

I take it that the electricity supplier give you an earth connection and that you are not using an earth rod in the ground.

Hi clive....

So this is what I'm at now.

I checked all the stepper motor shielded cables, made sure they were insulated at the stepper motor end and touching nothing, then at the control box end they all go to the star point.

The VFD spindle/Z axis block is now earthed direct to the star point. ( No other frame earth, just the one on the Z block )

The VFD cable shield is earthed separately onto the same star block, and it's insulated at spindle end ( not touching the spindle )

The other AC appliances ( VFD + Wood chip motor + 2 x pumps ) are all earthed at the same star point where applicable.

On the earth side - I'm using the house common earth..... how can I test if this is faulty?


I was a little concerned about the cable shielding pushing an AC signal back into the stepper motor shielding, but it seems to be going ok, 40 minutes into a cut now

[Clive S]

The VFD spindle/Z axis block is now earthed direct to the star point. ( No other frame earth, just the one on the Z block )

Personally I would just earth the main frame not the Z block ( if you want to earth the Z block connect that to the main frame)

was a little concerned about the cable shielding pushing an AC signal back into the stepper motor shielding, but it seems to be going ok, 40 minutes into a cut now

Let us know how you get on.

Still no pics of the control box !!

[dachopper]

[dachopper]

The stepper ground is temporary as I was still trying to troubleshoot

[Clive S]

The stepper ground is temporary as I was still trying to troubleshoot

Ok It is always better to use twisted pairs for the step and dir wire from the drives to the control board just chop a cat5 cable up.