Use of spindles and VFD

Machine I am running Maslow - M2 Jumpstart
Modified and built my own Z Axis, very similar to the M2, but with a spindle holder. So I have fitted a 800W water cooled spindle and wow!!! what a difference in terms of noise it is so quiet. You can still hear the screech and whine of the Maslow motor but probably the loudest sound is the Variable Frequency Drive (VFD) controller (actually the fan inside it) that controls the speed of the spindle. …

The issue is that when you turn on the spindle it causes havoc with the Maslow control system, the network links drop out and all sorts of chaos, and its anyones guess where the sled will go. Obvious the VFD and/or spindle are setting up some interference (they can run up to 400Hz) which I was sort of aware that it would happen, but not so catastrophically.

Has anyone any experience of this problem and, if so, how did you overcome this.

My first thoughts are to put a shielded power cable from the VFD to the spindle. Then I plan to put some distance from the VFD and the electronics by moving the Arduino to the top right of the setup (near the motor) and set up a Pi for Web Control (feeding this with ethernet rather than WIfI). The VFD is resides on the left hand side. I think I might have to shield the Maslow motor cable, perhaps replace them with shielded cables as well.

Any help greatly appreciated…


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shielding cables (both the power cables to the spindl and the maslow motor
cables) is a huge step

another thing is to try and make it so that you don’t run the spindle power
parallel to the maslow cables.

David Lang

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I run a 500w spindle and vfd. The vfd and maslow electronics are mounted about 4 feet apart. The spindle power cord is routed to the sled from the floor and the z axis harness comes down from the top to minimize contact/interference. Webcontrol on my laptop is connected direct via USB.

I have never had any of the issues you are experiencing but have always kept the wires, vdf, and maslow electronics separate.

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Would it be possible for you to put links up or specs of your spindle and vfd set-ups, I’m interested in swapping out the router.
Also would the spindle work with the M4 with the problems of interference as the electronics are on the sled.(Maybe a Question for @bar )

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Contrary to regular shielded cables it is often beneficial/recommended to ground both ends of the shield on your power cable. You also want to ensure the motor case is grounded.

I haven’t tested it so I can’t say anything with confidence. I like the idea of having a spindle option if we can find one that is reasonably priced and also good. I’m super open to recommendations to try.

I think I disagree with grounding the shield at both ends.

When you do that, the shield is just another conductor.

The sales guys that sell the VFD rated power cables advise grounding on the supply side (Power source) only.

Cheap and easy to try would be wrapping tin foil around the power cable to the VFD, and tie that to ground at your power base (assuming that you have a power bar powering up all of the Maslow stuff). If it helps, you can pursue further. If not, you didn’t waste much time or effort

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even just another conductor will block radiation from the wires inside of it.

(not saying you should attach the ground on both sides, but if you have a metal
shell on the motor side, I could see value in that being grounded to act as a
shield as well)

David Lang

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Many thanks to all for your very swift responses. Your right the spindle is metal framed and has a metal ( shrouded) connector going to it, both of which are connected to the electrical power earth ( “ground” in US speak). Thus l8kely that shielded cable is l8kely to b3 connected both ends of the supply and spindle. Anyway I will give it a try… may even just wrap foil around the Maslow motors and see if that helps. The Arduino and Pi will be put in a metal case, located well away from the VFD, and as I said before fed with an Ethernet connection so no reliance on WiFi needed. Onc3 again t@nos for all the help, I will let you know how it goes.

A bit of an update on using spindle. I have now resolved the matter of the EMI. I installed a shielded cable for the supply to the spindle (from the Variable frequency Drive (VFD)) but this did not rsolve the situation. After watching a YouTube video about EMI issues of using a spindle on a CNC, I put a EMI mains filter (10A filter available on Amazon UK for about £8) on the supply to the spindle controller (VFD). I also put some ferrite cores around the outputs of the VFD . I can now start and run the spindle without any interference causing drops, and comms links appaer to be stable.