Ah. I was thinking they were placed in each lead, but filtering the common mode makes sense.
----- Original Message ----- From: "John Kasunich" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Sunday, October 28, 2007 7:40 PM Subject: Re: [Emc-users] Threading Hickups > Javid Butler wrote: >> If you do use the ferrites in the outputs let us know how much heat they >> produce. I would guess it will be a function of the quality of the VFD's >> output stage, but have never tried power ferrites. >> >> The filters used in theatrical dimmers can get pretty hot, and those >> frequencies are low compared to a VFD. Since ferrites are more lossy at >> high >> frequencies I'm curious about it. >> > > In my experience, ferrites are used on VFD outputs to filter common mode > noise. For that purpose, all three VFD leads go through the ferrite > together, and the ferrite doesn't "see" the motor current, it only sees > the common mode current. Under that condition, heating is minimal. > > If you put ferrites around the individual motor leads, the motor current > will probably saturate the ferrite and make it ineffective, as well as > producing core loss that heats up the ferrite. > > Regards, > > John Kasunich > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
