Originally Posted by Bob Lee (QSC)
What do their power "conditioners" (or any other brand's) actually do?
Most "Power Conditioners" are over-hyped TVSS units, though they may have multiple functions. There are several functions that fall into this category:
> TVSS - Surge Supression. This is a reasonably valuable function, and serves to limit the number of transients that the MOVs in your equipment power supplies have to absorb, thus helping to extend their life. However, most of the devices on the market don't publish specs that really tell you how they perform (peak surge current, clamping time, clamping Voltage), so there is a lot of over-pricing and hype in this area.
> Series filtering. This is designed to get rid of high-frequency noise on the power lines. It can be valuable if you have noise sources in the house like electrically noisy motors in a refrigerator, HVAC unit, compressor, etc. They are unneeded in all but a few problem installations, but they won't hurt anything.
> Voltage control. This is generally in the form of Voltage limiting, as opposed to true buck/boost regulation. Depending on the technology used, this can actually cause as many power quality problems as it solves.
Now, a really GOOD power conditioner would operate like a double-conversion UPS, converting the input power to DC, then using an inverter stage to re-create the output AC wave. They exist, but they are not for the light of wallet.