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
