Earthing?

[the great waldo]

Thanks Jazz
As the screen for the steppers is connected at the socket via the chassis should I leave both ends of the screen unconnected or is it better to run the driver end of the screen to the bus bar?
Thanks again
Andrew

[Clive S]

Thanks Jazz
As the screen for the steppers is connected at the socket via the chassis should I leave both ends of the screen unconnected or is it better to run the driver end of the screen to the bus bar?
Thanks again
Andrew

Others might have a different view but I have done it like you and grounded the screens at the sockets and the plugs. But then I connected a ground wire bolted to the panel close to the sockets and ran that to the star point.

Then you don't ground the other ends of the cable ie at the driver or motors

[the great waldo]

Thanks Clive.
Just for other forumites make sure there is continuity on the chassis holes for the sockets. On my box only one socket made a connection, all the others were insulated by the case coating/finish. This needs to be corrected.
Cheers.
Andrew

[Neale]

Thanks Clive.
Just for other forumites make sure there is continuity on the chassis holes for the sockets. On my box only one socket made a connection, all the others were insulated by the case coating/finish. This needs to be corrected.
Cheers.
Andrew

I'm also using an epoxy finish steel cabinet, and don't trust any mounting bolts to earth to the cabinet. I've used ground wires from sockets back to the star point, which is a stud welded to the inside of the cabinet.

[Clive S]

I'm also using an epoxy finish steel cabinet, and don't trust any mounting bolts to earth to the cabinet. I've used ground wires from sockets back to the star point, which is a stud welded to the inside of the cabinet.

Yes I should have said that as I have also done the same thing with the mains earth to the star point.

[m_c]

The key thing with grounding, is to avoid ground loops, which you potentially create anytime a screen had more than one ground connection.

However, in power wiring, ground loops aren't likely to be a problem. The point of grounding in power wiring is to contain noise. A ground loop there is unlikely to cause any problems. A prime example is if you wire up a VFD as per most manufacturers recommendations, you ultimately create a ground loop in the wiring, as the motor is likely to be grounded through the machine.

It's in signal wiring, especially low voltage i.e. 5V, where ground loops are far more likely to cause problems.