3 Phase Power Failure

We have a bunch of the ETC SmartBars in one of our black box performance spaces and we recently had a power failure on one of the phases of power coming in to the building.  It caused some of the ETC SmartBars to start acting up.  Some of the dimmers wouldn't fade up when they came up in a cue, and instead started acting like a non-dim.  When I cycled the power on the breaker that fed the three phase circuits in that theater, they all seemed to restore to their original state.  It was very odd that only a few of the SmartBars "freaked out" when they all would have lost power.  

We also had the Element get a bit confused too, for some reason a handful of the addresses in the patch suddenly had a profile put on the dimmer curve.  In the end I wasn't on top of it enough to actually cross reference the dimmers that had the profile curve and the dimmers that hadn't been working properly since cycling power actually resolved most of the problem.  I'm wondering if the two were related though. Is it possible that the dimmers sent information back thru the network and somehow forced a profile on to the console?


Brian Walker

Production Manager

Midtown Arts and Theater Center Houston

  • The SmartBar behavior actually makes a lot of sense if you have 6-circuit bars wired for 3-phase input. Those also have the option of bi-phase operation so if you happened to lose the B phase, then the bars could* go into bi-phase mode. That means dimmers 2 & 3 would behave exactly as you described. If the phase that dropped out is wired as A or C for some of the SmartBars, then those would not be affected in the same way. Aside from the improper dimming performance there's no harm in any of this and, as you found: resetting power should clear up all the confusion

    I'm not sure what happened with the console, but it's unlikely to have been related to the SmartBars' confusion.

    *This would be most likely if power drops out completely for a moment, then comes back with only two of the three phases.