Speed control dial does nothing on VFD (SOLVED) & VFD wiring

That would be great if it output RPM vs Hz, now to find that setting…Thanks

Hey Jay,

you can zap through displaying frequency, current, rotating speed, voltage, counter,
temperature, forward/reverse status, fault, etc. with the keys on the operator panel.

For setting default monitored value to “rotational speed” try to set F170 to 2.

Also since most 24000 RPM spindles with magnetic 2 poles have a minimum speed allowed by manufacturer of something between 8000 and 6000 RPM and running them slower can damage them, it would be good to set “F011 Lower limit of frequency” to something between 133 and 100 Hz.

The rotational speed of the spindle is calculated this way:


e.g. 400 Hertz × 2 × 60 seconds / 2 poles = 24,000 rpm.
e.g. 133 Hertz × 2 × 60 seconds / 2 poles = 8,000 rpm.
e.g. 100 Hertz × 2 × 60 seconds / 2 poles = 6,000 rpm.


Alright now that I know this unit is working as expected I am moving forward and buying some better cables.
Just picked up a cable off Ebay, VFD Cable 10ft 16/4 DS Flexion For Spindle .8Kw 1.5Kw.

Any suggestions on converting the 2 wire power in, to have a ground wire?

I just found my DB25 breakout module…forgot I even got this pc it’s been a while…lol

Keep pushing forward…

Hey Jay,

Protective Earth on input of VFD is mandatory! You need a 2+PE cable there.

See here and here for details.

See also here:

So a good power cable for the wall to the vfd would be a 15 gauge 4 wire cord pre wired on one side with a 3 prong plug and loose wires on the other end to except xxx type connector to solder or pinch on?

Hey Jay,

No, not 4 wires on input. For VFD input, which means wall outlet to VFD, you need a 2+PE cable, which according to Adam Ries is 3 wires. All protective earth wires of the system have to be brought together in one point which should be the metal plate as seen in the picture above (to which the VFD is screwed with its metal back, the metal plate is usually part of a control cabinet case).

yes, for the wall to VFD, a three prong plug for safe connection to your house earth, and at the other end three loose wires to which you have to crimp connectors. You should not need to solder something. The wire ends are crimped to either ring connectors or wire ferrules (dependent on the type of terminals on the VFD) with matching crimping pliers. Please avoid having the wires (which are stranded wire) without one of both, ring connectors or wire ferrules!

Jay, attempting to wire a spindle and VFD, for which a certified electrician is required, is a serious thing. Please be sure to acquire the knowledge needed before.

Please do follow the links I mentioned above and the links you find there, there is much information there.

Got to leave now! It is 06:59 in Central Europe.

PS: This is now off-topic according to your subject line. Please consider continuing the topic e.g. by joining here.

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15 gauge wire isn’t a common gauge wire, 14 is. I use an extension cord and just cut it to the desired length vs making one up for something like this. I didn’t for my VFD since it’s 240v. If you’re in the US go to any hardware store, pay attention to what size wire is in the cord and get one slightly longer than you need and just cut to length. You’ll have a cord with a molded plug on the end. I would use a ferrite bead on the power cord. Chances are that’ll be enough unless you have noisy power at your location. Then an EMI filter would be better.

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Hey Alex,

the EMI filter on the input side of a VFD is to protect the house installation and other electrical devices connected to it from the EMI the VFD produces.

– Source: Omron MX2 User’s Manual

What protects the VFD from power distribution system is the input-side AC reactor:

Dr. Al, Thanks for the suggestions about what to use.
I have a few extension cords and power cables around that I could cut.
The post above my 15gauge post I do not understand in the least what a earth plate is or any of the links it contained.
I am an end user looking for suggestions on what products can be used vs what electrical theory says about my question.
Basically I am no electrician but I am an electronics technician that can follow directions well.
So if others want to share what products work for them and how they accomplished their goals I am all ears.
Many many thanks, just trying to clarify what I understand and that I appreciate all the help I can get.
Thank you all!!

Hey Jay,

as you can read in the post above, it is recommended to enclose the VFD into a metal enclosure because a VFD produces a lot of EMI. A metal enclosure is able to prevent the EMI spreading around (Faraday cage). That is the same reason why you use a shielded cable for the connection between VFD and spindle: VFDs do not produce nice sine waves, but rather rectangular pulses, and that means electromagnetic dirt. A control cabinet for your VFD looks this way:

You see there is a metal plate in it, on the back. For mounting the VFD, you loosen the metal plate and drill holes into it where your VFD and other accessories (e.g. EMI filter) need holes. After having attached the VFD and the rest you put the metal plate back into the cabinet and connect the earth to it and also all earth wires from other parts of your installation.

On the lower side of the cabinet you see the holes for the cables to mains power, to controller, and to spindle.

Correctly and professionally (=safely) wiring a VFD is at the limit of things end users do (or beyond). As said before, it requires a certified electrian, so if you have the least doubt in being able to acquire the part of knowledge of an electrician that is needed here, I would not attempt to do such things. For end users, there exist CNCs with milling motors that are ready-to-use. A spindle with VFD is not.

Achieving such a task mainly is about safety. Understanding how especially grounding is done is mandatory.

Technically it’s for both. A VFD is susceptible to noise like any other electronic device. Ideally everything in a house/ shop will have shielding to protect against EMI and to stop the device from emitting EMI but we all know that’s not the case.

Here’s a quote from one of the companies that make EMI filters I use: An EMI filter does two things. First, it protects the VFD from high-frequency noise that is being generated by other electrical loads on the power supply. This additional layer of defense minimizes the impact of high-frequency electrical noise—and can help machine builders meet the CE machine directive for filtering. The second core benefit of an EMI filter is that it drains parasitic currents to the ground instead of conducting them back onto the supply cable.

Most people would be surprised by just how many things in their house that emit noise.


Hey Alex,

you are right. I always want to spot on the VFD being rather a device that produces EMI dirt than being endangered of catching some.

I understand the EMI noise part and ordered the double shielded wire ( VFD Cable 10ft 16/4 DS Flexion For Spindle .8Kw 1.5Kw) for the spindle to VFD.

I am concerned about the power in to my VFD as it currently only has two wires connecting to L and N. I would like to use a different cord with 3 wires. I do not know where to connect the 3rd wire to the VFD?

I see the metal box housing and will start to think about how I can incorporate this into my plans and if I might have something I can repurpose.
I see this build is complex and may need other components to get my water pump and vac to work together with the 1F. It is hard for me to tell what products I may need so I am just taking it slow and piecing together everything as I learn what I need.
Finding a list of what you need and what will work is most daunting at the moment.
Thanks for the help and support!!
Taking it slow, Cheers

Hey Jay,

Yes, concern is justified since you have no protection as long as the ground wire from your spindle has no contact to your house grounding.

You connect it at the same point where the earth (yellow/green) wire from the spindle is connected: Somewhere at the VFD metal housing (as long as you have no metal plate). All earth wires have to be brought together in one point which ideally is the metal plate on the back of the VFD metal housing. See also the drawing here:

It shows three wires from mains wall outlet (2+PE) (upper left), metal plate with VFD and EMI filter, and shielded four wires from VFD to spindle (lower right), all with how PE and shields have to be connected.

By the way, here is an example of (nearly :wink:) finished VFD control cabinet:

Also I wanted to say that of course you can buy a Control Cabinet with VFD wired ready-to-use at some spindle manufacturers, e.g. here:

Electrical Cabinet AB007-E-V1-M

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Hey Jay,

The right attitude in my opinion :slight_smile: Learning this can be fun.

See e.g. here

Descriptions of this are spread around in the forum.

Thanks!! The pictures of the products help as I don’t know I need it yet…lol

I am making progress, added a monitor and mouse. Mouse while I wait on a game controller.

I can see I have wires and controllers stacking up on the edge of my table. A cabinet or metal box could be very handy. I understand and have access to ferrite rings. Most of the copiers I work on do have most all the controller pcb’s in a metal box on the back of the machine…so this does make sense to me.
So mechanically speaking I may need a metal box/cabinet, EMC filter, 5-6 relay switches, and…I know I am missing some stuff…
If there are common products users here like for this stuff and any specs about the mechanics known to work with the 1F…

I found Clough42’s YouTube channel very informative. The first two videos of his ATC spindle build - see below links - show and discuss his VFD enclosure. You may find them helpful as he refers to many of the points highlighted by @Aiph5u.


I have everything but the controller in an old computer case. The list includes the VFD, power supplies, solid state switches, etc. If you look at your VFD it looks like the control panel snaps into place. HY makes a remote kit (very cheap) that’s just a ribbon cable and a trim piece that the control panel snaps into. I made a control panel with switches for the dust collector, water pump for the spindle, power for the VFD, the display for the VFD, a pair of USB ports, and the water flow gauge. It mounts to the side of the display. I still need to get a joypad and keyboard holder.

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This sounds amazing Dr- Al!!
I just finished watching Michel Satoer’s control panel video and wow, way more control than I ever imagined.
I am currently looking for a metal cabinet box. I have an old PC and lots of old copy machines for parts.
I am putting a parts list together as I find out what specific pcs I may need. If anyone wants to share the components in there build, please do.
Thanks, this is lots of fun!!

Hey Alex,

you are too modest to show how it looks like? :slight_smile: I always like the pictures of your setup:

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