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deannos
27-11-2011, 12:27 PM
As the title suggests i have put everything into an old PC tower case. Know i have been told i have to earth the cable screening at one end only. But what do i earth this to, the PC case. Do i have to earth the PSU and what about the case. On the PSU i have a connection marked as FG (googled it as frame ground) what do i do with this:confused::redface:

Jonathan
27-11-2011, 01:03 PM
You should connect the mains earth to the computer case, and connect the now earthed computer case to everything else at one point. That's the screening, PSU and spindle if it's one with a metal body that's not already earthed.

russell
27-11-2011, 02:14 PM
As the title suggests i have put everything into an old PC tower case. Know i have been told i have to earth the cable screening at one end only. But what do i earth this to, the PC case. Do i have to earth the PSU and what about the case. On the PSU i have a connection marked as FG (googled it as frame ground) what do i do with this:confused::redface:
Which cable are you referring to? While, in principal if the PSU is built to Class 2 insulation specs it is not necessary to earth it, I would recommend earthing everything. The point of not earthing the screen at both ends is to prevent currents flowing in the screen which could compromise the screening efficiency. If necessary a separate earth conductor could be included. inside the screened cable.

Russell.

deannos
27-11-2011, 02:33 PM
Which cable are you referring to? While, in principal if the PSU is built to Class 2 insulation specs it is not necessary to earth it, I would recommend earthing everything. The point of not earthing the screen at both ends is to prevent currents flowing in the screen which could compromise the screening efficiency. If necessary a separate earth conductor could be included. inside the screened cable.

Russell.

The cable is 4 core screened and i have used this to connect the motors to the drivers and also to connect the drivers to the BOB

russell
27-11-2011, 02:43 PM
The cable is 4 core screened and i have used this to connect the motors to the drivers and also to connect the drivers to the BOB
If both the drivers and BOB are inside the case they do not need screened cable between them. The screen of the motor cable should be connected to the case and left unconnected at the machine end. Both the machine and the computer case should be earthed via the mains cable.

Russell.