I installed two 3-pole IEC style Siemens lighting contactors to control 6 circuits of fluorescent cove lighting. I'm energizing the 120v coils on the contactors from 2 non-dimming modules from an EDI dimming system so the fluorescent lights can be controlled through the dimming system (the non-dim modules have either 120v or 0v, they do not act like at all like a dimmer). When I run up the channels controlling the non-dimming modules, I can get the contactor coils to energize but when I run the channels down, the coils won't release, they just chatter. I tested voltage across the coil with a digital meter when I ran the channel all the way down and I have 0 volts but the only way I can get the coils to release is to shut off the breakers feeding the non-dim modules. A rep from EDI suggested that I need a add-on resistor for the contactors because the dimming system uses SCR's and there isn't a ground reference but I'm not sure what add-on resistors are. Any help would be greatly appreciated.
Lighting Contactors and Dimming Systems
- Thread starter bmcghee
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Re: Lighting Contactors and Dimming Systems
I assume your lighting contactors electrically held? And I'm not sure what you mean when you say you are "running the channels up or down"? Aren't they stricly On or Off?
I wonder if it is possible that the contactor is causing a spike when the module tries to shut it off. That spike might cause false triggering of the SCR in the EDI output module, thus turning the relay back on.
Try connecting one fixture (maybe incandescent) across the EDI output along with the contactor. That should abosrb any surges. If that makes it work, then you might see about getting a surge supressor that goes across the relay coil (that's an option available for some contactors).
Steve
I assume your lighting contactors electrically held? And I'm not sure what you mean when you say you are "running the channels up or down"? Aren't they stricly On or Off?
I wonder if it is possible that the contactor is causing a spike when the module tries to shut it off. That spike might cause false triggering of the SCR in the EDI output module, thus turning the relay back on.
Try connecting one fixture (maybe incandescent) across the EDI output along with the contactor. That should abosrb any surges. If that makes it work, then you might see about getting a surge supressor that goes across the relay coil (that's an option available for some contactors).
Steve
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