Inventables Community Forum

X-Carve Pro and Blowing GFI Circuits

I built my X-Carve Pro this weekend and ran into a strange problem. When I got to the step of powering up the controller I found that the moment I turned the unit on it tripped my circuit breaker. Here our local code calls for all new circuits to be GFIs and this was a brand new circuit.

I talked with support on Monday and they told me that they have been seeing this with people using GFI outlets but had not heard of it yet from a GFI circuit breaker. They asked me to use a different circuit that was non-GFI. Using an extension cord I was able to test it using a non-GFI circuit and it seemed to work fine.

This makes me very nervous as a GFI measures leakage between the hot leg of a circuit and neutral (corrected), indicating there is a problem with the circuit/device. Support says it is because of the current surge to the stepper motors. I am not really buying that the stepper motors when idle are drawing enough current to trip the breaker.

One of the first things I did in testing was to remove all cables from the controller and then try powering up the unit and it still tripped the breaker.
I suspect there is some kind of design issue with the controller that is causing leakage between the hot leg and neutral (corrected). Right now I am not comfortable with keeping my X-Carve Pro plugged in until I know more.

Anyone else has any experience with this?

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A GFI monitors the hot and the neutral (not the ground). It works by matching up the current from the hot and the current going back through the neutral and making sure these are the same. If they are not, current is leaking in or out of the circuit from another source. It does not have to be much current difference at all and the GFI will trip in a fraction of a second. Your GFI breaker is tripping for GFI reasons and not for high current reasons.

Most resistive type loads (things like space heaters) work fine with GFIs. Some inductive loads (some motors) and loads that mess with the Power Factor can trip GFIs.

It is unlikely that the stepper motors are tripping the GFI since these are on the DC side of the power supply and a GFI will not fault for leaks on the far side of a transformer. The issue is almost certainly in the power supply they have chosen.

I fully agree with you. If the controller keeps tripping the GFI, it is probably not safe to use.

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Thanks for the clarification Harry.

My X carve pro is doing the same thing and I have disconnected all the stepper motors and I agree with @HarryC.Ragland that the power supplies in the control unit have a problem. The controller is basically a PC and it trips a GFI circuit that makes no sense at all? I have also had to re wire my barn and add an outlet that is not GFI to run my x carve pro which is also out of code in my area. Meanwhile I can run every single piece of wood working equipment never have tripped a GFI and have no issues at all. If something happens to my machine they better cover it because based on this forum post there are some more folks out there having this issue and I believe there might be something not quite right inside the controller?

Support says that engineering is looking at it now. I ran this by my buddy who is an Electrical Engineer and he said the same thing. He thinks there is a problem with the power supply.

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I put mine together Friday night, powered it up went through the steps in easel. Moved the axis’s around using easel, then shut it down. The next morning, turned on the power switch and heard a loud pop. Power light is on but it wouldn’t connect. Pulled the cover off the controller to find the fan on the power supply is not running. Thinking something in the power supply exploded.

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I’ve had similar issues in the past where there was a ground (earth) current leak between the equipment and the controlling PC. You might try verifying that the PC and the XCarve are powered through the same GFI circuit.
If they are, it might be necessary to connect the USB through an isolation device to keep from connecting the conflicting ground circuits. Not sure what to use for that - last time I addressed such a problem it was using serial ports (and there were serial port isolation solutions available at the time. Opto-isolators I recall).
My experiences for what they’re worth. Your mileage may vary…
Brent

So following Brent’s post I decided to try again making sure the PC and the controller were on the same circuit. They were not before. I started by unplugging the USB cable from the controller and then powering the controller back on after plugging it back into the GFI circuit. The result was it DID NOT trip the breaker. So assuming Brent was right I plugged the USB cable back in to see if there was a trip… Nothing. I cannot reproduce the problem that was consistent before. I am not sure what has changed other than I have put some time on the machine.

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I suspect that if you were to go back to the controller and the PC being on different circuits, the GFI would go back to popping. The stray current is leaking from one circuit to the other across the USB.

When both the controller and the PC are plugged into the same circuit, despite the fact that the USB is leaking current, the GFI will not trip because the GFI looks at the total current in and out at the mains wiring and does not look at each receptacle individually. The stray current balances out by coming in one machine, passing over the USB and returning through the other machine through the single GFI.

It sounds like something in the controller is not right. Inventables should have a skilled Electrical Engineer carefully review the design. They may also want to HI-POT test the units.

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I’m glad to hear that putting the computer and XCarve on the same GFI circuit seemed to help.
I suspect that the current leakage issue is coming from the cheap power supplies used in the XCarve and the PC. No slander intended against Inventables - everyone including the PC makers used similar cheap power supplies. These supplies vary in the way that they handle earth/ground and that brand-to-brand variance is what shows up as a current leakage. I think it comes from the way they internally set the 5 volt, 12 volt, etc. (DC in general) ground as referenced from the switching supply circuit.
In any case I’m glad everything seems to be working now.

I spoke too soon. The problem returned after a short time. I hope they find this issue soon.
D

I also ran into this same exact issue.
New home construction (literally 2 months old at the time of the XCP delivery).
GFCI in the garage was tripping.
Tried multiple outlets. Same gig.

Luckily, i had a 20amp dedicated installed, so i used that instead.

The suggestions I got from support was to try a non GFCI outlet.

I’m having this same issue. Luckily I found an alternative circuit in my garage that runs the garage door openers.

I guess I am just here to confirm that this happened with me as well. Tripped the outlet on the circuit I was using it on. Moved it to one that did not have GFCI outlets and all was good.

Hey I just spoke with our engineers and wanted to provide some clarity about what is going on:

The spindle is powered by a variable frequency drive (VFD), and it is common for VFDs to generate some current that flows to ground due to the high frequencies and capacitive coupling between current carrying conductors and grounded elements. This ground current can generate nuisance tripping of the GFI since it creates an imbalance between the current on the hot and neutral lines. The X-Carve Pro was not designed to operate with GFI outlets and is functioning as intended. Do not modify or open the controller as this could cause a safety hazard.

We recommend plugging your X-Carve Pro into the nearest non-GFI outlet to avoid this issue.

Sorry about any confusion surrounding GFI and the XCP in general. Let me know if you’ve got any other questions!

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Thanks Brandon,
I was able to do some reading on this and it appears this is common with VFDs as you expressed. Thanks for checking this out. I feel better about leaving my unit plugged in now.
D

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Had an electrician out today and he was doing work in the sub panel that powers the Xcarve along with many other items in the shop, he noted he received a shock from the grounds while performing work. Not sure if this is related due to the weather raining out any troubleshooting. Tomorrow I’ll unplug the xcarve prior to investigating where else it could come from.

This issue has only presented itself since the XCP was installed. Benefit of the doubt says some animal may have crossed some wires in the electric of the garage. I’ll keep everyone updated. I would hope there isn’t enough feed back from the spindle to cause shocks.

I’m having this issue with every outlet I’m using. I’m using my garage as my location for my XCP. There is one GFI and several other outlets that are not, all of them are tripping the breaker. I have also run an extension cord into my house and tried those outlets and those aren’t working either. My house is about nine years old so I wouldn’t think that the circuits would be an issue. I’m not sure I have a circuit that does not have a GFI on it. I don’t have the greatest knowledge when it comes to these kinds of electrical issues, any advice would be greatly appreciated.

If the outlets are tripping the same breaker this oj the same circuit it is a rather common practice to use a single gfci outlet and then connect all of those standard outlets into it.

Here’s a really dumb way, my master bathroom has no gfci outlets, but its code to have gfci in all bathroom outlets, one day the master bathroom outlets (2) both have no power… well it turns out they get their power from the grci outlet in the 1/2 bathroom located directly below the master and one of my kids bad pushed the trip button :man_facepalming: that only took 20 minutes to figure out, and only because I walked by that room on my way back from the perfectly fine, I tripped breaker panel & happened to notice the yellow glowing light in the dark room…

But you mentioned the breaker is tripping? They do make gfci breakers so the builders don’t have to do the weird daisy chaining like mine :man_shrugging: I would take a closer look at the breaker and try to determine if you actually have a gfci breaker. Otherwise it also could be possible that your Pro is actually pulling more power than the breaker is rated for and its rightfully tripping for that reason. I use a 20amp breaker dedicated to my cnc alone just to be safe :+1:

Is your circuit breaker one that has a GFI built into it? A GFI breaker will have a “test” button on it in the panel.

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