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    smchenry
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Firing mode to "switched" for non-dimming operation?

For the next few months, I'll be working in a temporary setting where we would like to hang some movers (Mac 250 washes, if it matters), but the only available power is all dimmer circuits (fed from Sensor racks). There are no alternatives. Having never been in this situation, I just wanted to make sure that I have my facts straight before I blow a few thousand dollars-worth of equipment... I've read both online and in the Sensor manual that setting a dimmer's firing mode to "switched" outputs unregulated AC when the control level is above the threshold, etc, etc. Is it correct that this mode would allow us to operate our fixtures without blowing our power supply and/or frying the on-board electronics? If not, what is the correct setting, or is this simply a no-go? Thanks.

  • In a word, NO, you should not do this.

    Some add'l reading:

    http://www.etcconnect.com/img/whitepapers/SB010-Options_for_Non-dim_loads_bulletin.pdf

    http://www.controlbooth.com/forums/lighting-electrics/19842-powering-moving-lights-through-dimmer.html

     

    In general, a sinewave switching device is not a good power source for movers. It will be far cheaper to rent relays and/or constant power modules (that have a breaker only) then to repair fried electronics on the movers.  

    Steve B.

     

  • in reply to Steve Bailey

    Unfortunately, any hardware-level modifications to the existing system won't happen due to a number of factors (Believe me, if there was any way, we would have gone forward with it). From the reading I've done, in switched firing mode, Sensor dimmers are said to output an almost perfect sine wave (I think it even said again that in one of your links). Additionally, Martin lists the power factor of these fixtures at 120V and 60Hz, the settings we'd use, as being 1.0, meaning that a dimming module would get the job done, right? Even the content of your links argues that, under these circumstances, we'd be alright. Is my thinking flawed?

  • in reply to smchenry

    I wouldn't call swapping a dimmer module a "hardware modification"- the dimmer rack is designed to allow this easily.  I understand that there may be other (non-technical, i.e. political) issues that prevent you from renting/borrowing relay or constant modules and exchanging them for the dimmer modules.

    Yes, the Sensor dimmers will output an almost perfect sine wave.  Whether that little bit of distortion will cause a problem is unknown.

    I don't think you'll find anyone who will definitely say "Yes, powering the fixtures from a dimmer won't be a problem"- it may work for a while or the MACs may blow up.  Martin says to not do it, so you won't have any recourse if you try it and things end badly.

    -Todd

     

     

  • in reply to tdrga

    Thanks, guys. I really appreciate the input. And Todd, you nailed it. Corporate bureaucracy and protocols in our rented space is the roadblock in nearly every direction.

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