[capdenny]

Can some one please explain how I can ground my cnc in layman terms so I can understand how and what to ground. I have a china zone 3040.

Thank You,
Dennis Killian
AKA capdenny

[john-100]

Hi Dennis

which version of "3040" CNC machine do you have ?

photos of your machine will help



grounding has two functions

first for your safety

grounding on Chinese equipment can be hit and miss

very often the ground wire from the mains inlet that should ground the control box is screwed to the painted surface inside the box !!!!!

also the ground terminal on the spindle motor is not always connected even though the motor has a 4 pin connector -
3 pins to connect to the 3 phase motor windings and the 4th that should ground the motors case !!!

taken from another post -

a picture of adding an earth connection inside a spindle motor
Attachment 384060

the other issue I have with these Chinese control boxes is the use of a 5 pin chassis plug for the spindle motor connections- should be a socket as it has mains voltages on the exposed pins !!!!

live pins on chassis plug for spindle motor !!!
Attachment 384062

so you need to double check the continuity between your supply ground and any external metal parts of the control box and the machine

the second ground function

to prevent electrical noise from the stepper & spindle motor wiring being picked up by the low level control signal control wiring

the grounds to the screened signal wires being connected by individual wires to a "star point" which is a common ground in the control box and not daisy chained

there are pros & cons for grounding one or both ends of the screened cable

the simple approach is to ground one end of the screen

with industrial machines where the machine is at equipotential you can ground both ends

( you may find its more difficult to ensure your chinese machine and its control box are at the same potential so connecting
both ends of the screens do not result in unwanted currents circulating in the ground loop )

john

[Kev Brook]

Hi, these motors don't usually need grounding, mine isn't,. Is there a reason you wish to do this, or do you have a problem with your machine not working / machining properly

[Al_The_Man]

Hi, these motors don't usually need grounding, mine isn't,.

All mains powered equipment over 50vac that is not double insulated requires earth grounding for safety reasons, in most jurisdictions.
Any equipment sourced from China etc may, or may not conform.
As John points out the other reason apart from the safety issue is to reduce or eliminate electrical noise, any mains fed equipment that is fitted with low voltage electronics should be earth grounded using the Star (one point) ground system, and/or something called equi-potential bonding in order to prevent ground loops which are a source of noise.
Al.

[mactec54]

Hi, these motors don't usually need grounding, mine isn't,. Is there a reason you wish to do this, or do you have a problem with your machine not working / machining properly

In the UK and most other countries, it would be a code violation, if you did not have a Ground / Earth wire, connected for any 220v to 240v 3 Phase motor

Another reason it is even more important for a VFD driven Motor is to dissipate the rotor voltage to Ground / Earth, instead of through you, when you touch the machine, or your machine control, which can damage your electronics

[capdenny]

Hello,
I am the originator of this thread and I am still having problems. I did ground machine and control box and ran a program. It ran for 30 mins and stopped, the message mach3 gave was a VB failure Check system. I do not know what a VB failure is so could someone help.

Thank You,
Dennis Killian

[john-100]

I would take the VB error to be a problem with microsofts visual basic
are you using a hacked chinese copy of Mach3
or a copy downloaded from Newfangled solutions - Mach3 - Newfangled Solutions

John