Harmonic Trap Filter Issue Revisited

Well, I can now report back on what we found with the Harmonic Trap Filter issue and running on a Generator.

Problem:
Multiple VFC's with attached Harmonic Trap Filters.  All connected to a back-up Generator.  The Gen-set was having trouble with the VFC's all on line but only half of them in service.

We installed Contactors in the Filters to disconnect the Capacitor Section of the Filters when the VFC is not running.

This fixed the problem.  It seems that the extra capacitance on the system was raising the voltage to a level that the voltage regulator on the Generator could not compensate for.  This was causing the Gen-set to trip out on Over Voltage.  Be aware that this is not as simple as just adding a contactor.  There is more equipment involved with this and various wiring changes that need to be made to make this work.  If you need more details, call me and we can discuss your application.

I have seen this now being asked for on several jobs that require a back-up Gen-set and the site having multiple VFC's, some that will not be in service during certain portions of the day do to the system demand.  So if you have a site that has this type of application and you are using a back-up generator, you have been informed and warned about possible problems you may experiance.

Just thought you may want to know....

Scott