Electro magnetic chuck near vfd

Cadillac

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So I purchased a SG that had a electric mag chuck on it. Not having 3ph in the garage all my machines are ran of individual vfds. Im in the process of cleaning the machine and rewiring the controls for the vfd. The control box for the machine is in its typical spot right side of machine just under table. The chuck control box is bolted to the side of the machine control box so all controls are close together. I think I have enough room in a distribution box of the machine to install the vfd and all other components.
My big question is will the electric chuck interfere with the vfd or vise versa when operating?????
Was sitting here trying to plan everything out and thought about it and I can kind of see a problem but idk.
Another thing that’s alittle different about this grinder is it has a direct drive spindle/motor meaning the spindle assy is integrated in the motor. The spindle is the armature of the motorNot the usual spindle linked to a motor via a coupler. Looks like a nice setup 2 sets of angular contact bearings for the spindle not the usual 3 bearing design.
Any thought on the vfd and electric chuck concerns obviously need these two components to work together. The chuck is ran off a 120v cord so it won’t be ran off the vfd but will be within two feet of each other.
 

mksj

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I do not see an issue between the two, the electromagnetic chuck is converted to DC I cannot see that it would be an issue. The control wires for the VFD, you could use shielded cable to the controls and just ground it at the VFD end. You may want to remotely mount the VFD or use a slightly larger metal sealed cabinet to minimize contamination.
 

Cadillac

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Thank you I didn’t know if the mag controller or wires going to the chuck or the vfd itself would cause problems. I’ve always used shielded wiring. Taking the foil wrap and twisting it to form a wire and grounding to the terminal on the vfd. I do get interference listening to my radio would something like that cause problems. Would you know how to fix that. It only interferes when the machine is running not when vfd on and a machine not running. You would recommend moving the vfd control panel separate from the machine to keep them apart? Would just need shielded motor wire correct? How far would be sufficient? Thanks for the response I wanna get all my ducks in a row so when she’s all cleaned up I can get her runnin quickly.
 

mksj

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You cannot use the VFD to run the machine is the magnetic chuck controls are integrated into the controls, A VFD would only be used to run the motor. Many machines use two of the 3 phases to run a transformer/power supply which controls other parts of the machine and the 3 phase is used to tun a main motor. SO I am considering that you are powering the mag controller from 240 single phase.

The radio interference will only occur when the motor is running, as this is the only time the output of the VFD is on powering the motor, and the electrical noise (RFI) is generated via the motor cable. Moving the VFD will not eliminate the RFI (probably make it worse with longer unshielded motor cables). If you are getting RFI there are a few recommendations, first is using shielded motor cable, so you need you need 4 wire which would be 3 wires for U, V, W and a 4th wire for ground and an outer shield. Some VFD's the ground wire is part of the shield, or it can be a separate insulated wire. The ground wire (when insulated) and shield are connected at both the motor and VFD ground. In addition you can get a power input filter, typically an EMI/RFI 240VAC line filter usually 25-30A for 2-3Hp. In some cases you can also use a ferrite toroid on the input/output wiring, the power wires (not ground) are wrapped several times around the toroid. Some examples below.

It is common to use remote switches to control the VFD functions, as the VFD is usually in a separate electrical cabinet. Also it my distance the enclosure from dust and contaminants getting into the VFD enclosure. So it is a matter of how you want to design your system. Their are sealed VFDs that can be mounted without an enclosure at the machine, they tend to be much more expensive. You could put the VFD enclosure anywhere you want, but if say on the back or side of the machine I would recommend a sealed metal cabinet with a gasket so metal dust would not get into it.
 

Cadillac

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The mag chuck controller has its own plug separate from the machine so yes it’s separate from machine power. I have been able to install the vfds in the machines control panel which is a metal enclosure. I tried to take precautions for dust by putting filters on fan intake and exh. seems to do well. Thanks for the link on the line filter I’ll get one on order and see how it works. I do have a bunch of ferrite chokes I beleive their called I just don’t know how to size or where exactly to install to make a difference. Been researching about about emi and rfi and honestly it’s hard to grasp. Getting there thanks
 
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