circuit breakers before a VFD

[newbiejason]

Learned something here. I want to add a sink for washing up in the shop, but it's going to end up being too close to a 220 outlet for comfort. I found that GFCI breakers exist for 220V and will be getting one prior to the sink installation.

Here in Australia there is still a minimum distance that an outlet can be away from a sink (500mm left or right)

Running your machine through an ELCB (earth leakage circuit breaker) can cause nuisance tripping as earth leaking from an electric motor is allowable down to 20k ohms, as do hot water services and electric cooktops.

 

[bezalel2000]

Running your machine through an ELCB (earth leakage circuit breaker) can cause nuisance tripping as earth leaking from an electric motor is allowable down to 20k ohms, as do hot water services and electric cooktops.

Hi Jason

That's one of the reasons 10 mA ELCBs are not popular on Aus

at 240V a resistive load of 20K draws 12 mA where as at 100V its only 5 mA well under the 10 mA trip level that appears to be preferred in the US.

So if you have a 10 mA ELCB tripping on a 240V motor then it could be operating normally. since anything less than 24K would trip it.

If your ELCB is 30 mA and it's tripping regularly then your Earth leakage is at or below 8K, IMHO that qualifies as a fault.

Cheers
Bez

 

[shred]

FWIW, my Teco FM50 VFD pops my GFCI outlet every time I turn it on. I did some investigating and ended up with "they do that". I'm not real happy with having to run it off an un-protected circuit, but there it is.

 

[willburrrr2003]

Ok, I build industrial control panels for a living in Seattle, WA. USA . If you are using a breaker with your VFD, only run the hot leg through the breaker. Make sure to have a good ground wire to your control panel. That being said, almost all of the major VFD manufacturers require FUSES ahead of the drive for protection, or they will not cover them under warranty. UL requirements call for fusing that limits the short circuit current possible though the device. All VFD's we wire are fused, since we are a UL shop. Fuse blow characteristics vs breaker, fuses will blow before a comparable breaker trips. Fuses offer equipment better protection for this reason as breakers let a bigger hit get to the equipment before the breaker trips. This is true of single phase power, and multiphase power. Verify which wire is your neutral wire, and which is your hot wire and wire accordingly. As for a VFD blowing a GFCI breaker, if the settings are more aggresive in the VFD then the inrush current is way higher than the GFCI is rated for, causing it to trip. If you fuse your hot leg/s make sure that your using the proper fuse for the application too( some are time delay before blowing, some are quick blowing, etc....)

Regards,

Will R.

 

[lectrician]

I am an electrician by trade. 40 years experience. No doubt about it, you need to run a separate line to the lathe. be sure to pull a large green ground wire in the pipe along with the power.Same size as the power wires or better. Do not use a breaker, use fuses before the freque drive. there is no need for a GFCI if you bond that green wire directly to your lathe and the ground buss in your panel. Don't depend on the cord to ground the lathe. If possible it would be better to go with a 240 volt feed to the freque drive. Plugging that thing into an unknown plug in your house is a huge fire hazard. Any further questions, i work with freque drive all the time at work. i may be coming into 6 of them that convert 230 single phase to 480 three phase soon. The the company is going to throw them away.