[john-100]

28mA is more than I expected ( I have to make a note for when I have a VFD)

by the time you add 3.5mA for the earth leakage for a PC's ATX power supply and possibly another 1 to 3 mA for the additional filter connecting the machines mains 15A supply fuses to the contactors C1 and C2 you are well over the 30 mA limit

John


Attachment 300168

example of a typical mains filter
Attachment 300170

note the two capacitors marked Y
the leakage due to the Y capacitor across live and earth is the cause of the problems
due to the symmetrical filter circuit being connected to an asymmetrical supply - the earth and neutral are connected together at the star point of the utility supply transformer

connected to the symmetrical American 220V supply terminals L1 L2 and earthed centre tap
the currents through the two Y capacitors will cancel ( assuming they are exactly the same capacitance)

[Eli_Ben]

Its almost certainly option 1. Does your machine have CE approval?
If that doesn't work check under the VFD and you'll find a small tab. Pull it down and it will disconnect the filter. I simply added another filter next to the breaking resistor - it may not be as good as the built in filter but I wouldn't recommend using the machine without one, and certainly not without some form of GFCI
Step

If you have the Emmerson VFD controller then there is a jumper you can remove that will stop it from tripping the RCD. The manual for the controller is online and it tells you about this. It worked for me and I run with an RCD with no trips when the spindle starts. Let me know if you need more help and I will try and find my manual and look it up.

Dave.

This worked!

I didn't realise you were both talking about the same thing. For the benefit of anyone else with this problem trying to follow along: The tab/jumper on the VFD allows you to easily disconnect the VFD's EMC filter. The filter was causing the GFCI/RCD/RCCB to trip every time the spindle started. So pulling the tab out solves the problem.

But this doesn't seem like a permanent solution as TurboStep, you mentioned that running the mill without the VFD EMC filter isn't a good idea. I'm curious to know what the drawbacks are of disconnecting the filter (not that I'm planning to leave it like that for long - it must be there for a good reason). Davebaldwin, have you replaced the VFD filter with anything? If not, have you noticed any negative effects?

I'd like to mention that Tormach themselves haven't been very helpful at all. They simply told me to consult a local electrician. This was surprising considering that 1) Their customer service is usually great. 2) This appears to be a known issue, and they have a good international customer base so this issue must have come up before. Perhaps they're covering themselves against liability in case something goes wrong.

But you have all been extremely helpful, so thank you!

[xjdubber]

This worked!

I didn't realise you were both talking about the same thing. For the benefit of anyone else with this problem trying to follow along: The tab/jumper on the VFD allows you to easily disconnect the VFD's EMC filter. The filter was causing the GFCI/RCD/RCCB to trip every time the spindle started. So pulling the tab out solves the problem.

But this doesn't seem like a permanent solution as TurboStep, you mentioned that running the mill without the VFD EMC filter isn't a good idea. I'm curious to know what the drawbacks are of disconnecting the filter (not that I'm planning to leave it like that for long - it must be there for a good reason). Davebaldwin, have you replaced the VFD filter with anything? If not, have you noticed any negative effects?

I'd like to mention that Tormach themselves haven't been very helpful at all. They simply told me to consult a local electrician. This was surprising considering that 1) Their customer service is usually great. 2) This appears to be a known issue, and they have a good international customer base so this issue must have come up before. Perhaps they're covering themselves against liability in case something goes wrong.

But you have all been extremely helpful, so thank you!

This is a known issue when you hook a VFD to a GFCI breaker, as tormach's main customer base is in the us, this is not really an issue for them. as in NA gfci breakers are not used for this purpose. Their advice to consult a local electrician is the right advise as he/she will know what your local regulations are on this issue.

[davebaldwin]

I have been running without the internal EMC filter connected and no replacement external filter for several years with no adverse effects or any complaints from the family that I am interfering with the radio, TV or whatever. It certainly has no effect on the computer, ipod music player, wireless phone or other machines in my workshop.

My understanding of the EMC filter is it is to prevent any noise being generated by the fast switching of high voltage signals being injected into the mains wiring. My workshop is separate from my house and connected to the consumer unit by 15m armour cable with a RCD in the workshop.

Dave.

[Eli_Ben]

Its almost certainly option 1. Does your machine have CE approval?
My understanding of circuit breakers (which may very well be wrong) is that they are guaranteed to trip at no higher than the specified current. That means that they can trigger at significantly lower levels, and recent measurements in my house would also confirm this. My PCNC 1100 will run from some outlets but not others - all are 30mA. Try a different outlet!
If that doesn't work check under the VFD and you'll find a small tab. Pull it down and it will disconnect the filter. I simply added another filter next to the breaking resistor - it may not be as good as the built in filter but I wouldn't recommend using the machine without one, and certainly not without some form of GFCI
Step

If you have the Emmerson VFD controller then there is a jumper you can remove that will stop it from tripping the RCD. The manual for the controller is online and it tells you about this. It worked for me and I run with an RCD with no trips when the spindle starts. Let me know if you need more help and I will try and find my manual and look it up.

Dave.

I have been running without the internal EMC filter connected and no replacement external filter for several years with no adverse effects or any complaints from the family that I am interfering with the radio, TV or whatever. It certainly has no effect on the computer, ipod music player, wireless phone or other machines in my workshop.

My understanding of the EMC filter is it is to prevent any noise being generated by the fast switching of high voltage signals being injected into the mains wiring. My workshop is separate from my house and connected to the consumer unit by 15m armour cable with a RCD in the workshop.

Dave.

Very interesting Dave, thank you.

I'm not sure if I'd get away without an EMC filter here, as my mill is set up in the integrated garage. One RCCB protects all the sockets in the property (including the mill currently), and another protects the lights, hob and cooker.

It sounds like it would be OK to go ahead and do some testing with the EMC filter disconnected. Or can the noise generated by the mill cause any damage to other devices connected to the mains?

[davebaldwin]

Or can the noise generated by the mill cause any damage to other devices connected to the mains?

I doubt very much if you will damage any equipment. The worst I would expect is to hear/see noise on radios/TV/audio equipment but I think you will be unlucky if this happens.

Dave.

[lens42]

Re ".......A GFCI breaker is a diffrent beast again, where the current between neutral and ground is monitored should it exceed the rating of the GFCI the breaker will trip. Should the ground be compromised the breaker will trip......."

Not trying to be pedantic, but the above statement is not correct. GFCIs work by detecting the difference between currents in the hot and neutral legs. They actually don't need a ground connection to function and, for example, will still save your bacon when installed in place of an old two prong outlet in a 60 year old bathroom even if you don't run an earth ground to the outlet. It's not code, but it's better than not using a GFCI at all.

[keen]

Sorry I have not read all this thread but sometimes when I spindle on the monitor goes off for a few seconds - unnerving - but the machine continues to run fine ....so I have just ignored it.

related issue?

Keen

[xjdubber]

Re ".......A GFCI breaker is a diffrent beast again, where the current between neutral and ground is monitored should it exceed the rating of the GFCI the breaker will trip. Should the ground be compromised the breaker will trip......."

Not trying to be pedantic, but the above statement is not correct. GFCIs work by detecting the difference between currents in the hot and neutral legs. They actually don't need a ground connection to function and, for example, will still save your bacon when installed in place of an old two prong outlet in a 60 year old bathroom even if you don't run an earth ground to the outlet. It's not code, but it's better than not using a GFCI at all.

Let me corret then GFCI's work by monitoring the difference in currents between hot and neutral legs as you say. However if that current level should differ from each other than that current is going to ground, trough you, or another object, and yes with the ground connected to the GFCI or not. If you do connect a GFCI without a ground, you need to note on the outlet that there is no equipment ground.

[lens42]

I just got a 770 and have to install some garage wiring. Is anyone using one on a GFCI outlet WITHOUT problems?


Sent from my iPhone using Tapatalk

[109jb]

"... They actually don't need a ground connection to function and, for example, will still save your bacon when installed in place of an old two prong outlet in a 60 year old bathroom even if you don't run an earth ground to the outlet. It's not code, but it's better than not using a GFCI at all."

Actually, the installation you describe would meet code. A 2-prong non-grounded outlet can be replaced by either another 2-prong non-grounded outlet, or a GFCI outlet without the ground attached. The only caveat is the GFCI outlet needs to be labeled as not having a ground. This is actually recommended over keeping the 2-prong outlet.

[matteo_galet]

Sorry I have not read all this thread but sometimes when I spindle on the monitor goes off for a few seconds - unnerving - but the machine continues to run fine ....so I have just ignored it.

related issue?

Keen

Hey, me too experienced the same behaviour!
I really can't explain which way the spindle could interfere with the screen... Noise on the DVI cable or on the power line?

Came on this thread because of issues with my newly installed 30mA RCD/RCCB; I had a defective one and - paradoxically - the Tormach worked fine!
I'll definitely go for a 100mA one and hope to solve the issue.

[Eli_Ben]

Hey, me too experienced the same behaviour!
I really can't explain which way the spindle could interfere with the screen... Noise on the DVI cable or on the power line?

Came on this thread because of issues with my newly installed 30mA RCD/RCCB; I had a defective one and - paradoxically - the Tormach worked fine!
I'll definitely go for a 100mA one and hope to solve the issue.

Weird. I haven't had that issue, but I do vaguely remember having problems with an unshielded VGA monitor cable when I first got the mill.

Regarding my original breaker trip issue, I've been running my mill with the Emmerson spindle VFD's EMC disabled (pulled out the tab on the unit). I haven't noticed any problems.

[matteo_galet]

I finally went for a 300mA RCD dedicated to the machine line and now it works like it used before.
I kept the 30mA RCD for the rest of the house though.