Can TRIAC dimmers cause lagging power factor?

The building that I manage has a film production sound stage with an old lighting system. It is not unusual for the stage to use 30 kW of lighting. In the past we have seen lagging power factor corrections on our utility bill that I have always attributed to our air conditioning load, but we just recently got hit with one when I know that we weren't using enough ac to cause it. My question is could the dimmers from the lighting system for the stage be contributing to the lagging power factor?

Thanks, for the confirmation! I've been trying to figure that one out for a long time. It feels good to know what it is now!


Senior Member
191213-1348 EST


Just look at your voltage and current waveforms in time relationship, and you will clearly see it.