Hi Brian:
I agree with Ted. The GFCI trips due to current. Leakage current is measured with a leakage current meter that doesn't read the higher harmonics. Measure the "leakage" current with a scope -- without the leakage current network. The GFCI works on difference current, and does not have the discrimination network used in leakage current meters. Best regards, Rich Richard Nute Product Safety Consultant San Diego > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf > Of [email protected] > Sent: Wednesday, August 15, 2007 7:10 AM > To: [email protected] > Cc: EMC PSTC > Subject: Re: Ground Fault Circuit Interrupter tripping > > > Hello Brian, > > I have run into a similar problem. The VFD is generating > harmonics which are likely causing additional leakage > current. If your product's leakage current is due to > Y-capacitors, you may have had a clean power source. In one > situation, I had a product that significantly increased > leakage current if the power was not clean. As the frequency > of the harmonics increased, the impedance of the Y-capacitor > dropped. Although the energy content of the higher harmonics > decreased significantly, the Y-capacitor allowed additional > current to flow resulting in a total leakage current high > enough to trip a GFCI. I found the susceptibility to this > problem to be closely related to the power source for my product. > > The problem may not even be due to harmonics in your product. > If the power in general is not very clean, the harmonics > will generate excessive leakage current through your Y-capacitors. > > The GFCI may not be falsely tripping. If possible, make a > measurement of the actual leakage current at the installation > where you have the problem. > > Ted Eckert > American Power Conversion/MGE > http://www.apc.com/ > > The items contained in this e-mail reflect the personal > opinions of the writer and are only provided for the > assistance of the reader. The writer is not speaking in an > official capacity for APC-MGE or Schneider Electric. The > speaker does not represent APC-MGE's or Schneider Electric's > official position on any matter. > > > > > "Kunde, Brian" > > <brian_kunde@leco > > tc.com> > To > Sent by: "EMC PSTC" > <[email protected]> > [email protected] > cc > > > > Subject > 08/15/2007 08:40 Ground Fault Circuit > Interrupter > AM tripping > > > > > > > > > > > > > > > > > > Some of our customers want to use a GFCI with one of our > products which has a frequency drive that runs a 1hp motor. > When this motor starts up the GFCI opens. We don't think the > problem is with leakage for our leakage current tester is > measuring less than 1mA. We are thinking that the GFI is > falsely tripping due to low frequency conducted emissions > caused by the frequency drive. > > Can anyone recommend a manufacturer of GFCI that would be > more immune to such false trips? Our product can run at both > 115VAC or 230VAC. > > What else could be causing the GFCI to trip that we are not > thinking about? > > Thanks, > The Other Brian > > LECO Corporation Notice: This communication may contain > confidential information intended for the named recipient(s) > only. If you received this by mistake, please destroy it and > notify us of the error. Thank you. > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] > Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] > David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] > Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] > David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.11.15/949 - Release > Date: 8/12/2007 11:03 AM > > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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