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Preventing the BCS from rapid ON / OFF with VFD on same circuit

Posted: Tue Aug 28, 2018 2:11 pm
by BREWMASON
What is the best way to prevent a BCS from triggering rapid relay ON/OFF ( from temps bouncing ) due to the polarity caused from a VFD, pump cart on the same circuit. It is plugged into a plug on the opposite wall but all ties into the same circuit breaker box. Have this happening at multiple locations when pump carts are plugged in.

Re: Preventing the BCS from rapid ON / OFF with VFD on same circuit

Posted: Tue Aug 28, 2018 2:21 pm
by JonW
Can you provide more information on how things are wired. Are you actually controlling the VFD pump from the BCS? If so, what kind of relay and how is it wired. Are the temp probe wires running alongside the pump wiring? This can cause inductance from the high voltage cable and entering the low voltage cable affecting the signals. Bottom line...need more info here.

Re: Preventing the BCS from rapid ON / OFF with VFD on same circuit

Posted: Tue Aug 28, 2018 2:48 pm
by BREWMASON
Completely independent and not running pump cart power cord near the temp probes or solenoid wires. The BCS-462 running in the control panel in question today is controlling a 10bbl and two 20bbl fermenters. Only the 10bbl ferm program was on with a delicious IPA inside. The pump cart was no where near any of these components. It was connected to some hoses in a loop circulating some sanitizer. I have seen mine in the garage on the 3bbl system behave the same way. I just disable the process and that prevents the solenoids from clapping as the temps jump all over.

Re: Preventing the BCS from rapid ON / OFF with VFD on same circuit

Posted: Tue Aug 28, 2018 3:31 pm
by JonW
Two other hobbies of mine are ham radio and home automation. In both of those worlds, it is well known that VFD pumps for wells, pools or AC units are some of the worst devices known for causing interference in other devices.

Do a google search on "VFD Noise Problems" for ideas on solutions to mitigate the problem. Your grounding is probably good, so you probably need to jump to doing either EMI filters or ferrite rings (or both). I've done ferrite cores on a lot of cables to fix amateur radio noise problems. They're cheap and work pretty good to clamp the noise and common mode currents.