Question about Power Factor

bmet · February 2013

I have added one of those air ionizers to my RV,since dust is ever an issue at the ranch. The RV is on grid power. KilaWatt shows 118VAC, 60Hz, uses a mere 8.5VA. The PF factor jitters around 0.69, and I'm curious if that is an indication of a problem. Air ionizers use high voltage to draw dust through its grids, and I can feel the 'draft' when it is on. With a PF of 0.69, should I be seeking a warranty replacement? Thank you.

niel · February 2013

Re: Question about Power Factor

while it's operating i can see there being small changes on the load and make the pf change slightly and the consumption is low so i wouldn't worry about a pf wobble. nowe, i could be wrong on this, but if it is working i wouldn't worry about it. of course, how would one know if it is working as ionizers just charge the dust particles so that they are supposed to clump together and fall down rather than be airborne?

BB. · February 2013

Re: Question about Power Factor

It should be OK... It takes work on the part of a power supply designer to make a PF~1.0 device. For the most part, small/simple electronic power supplies just clip the peaks off of the voltage sine wave (current draw "spikes" only during the +/- peaks) which give poor power factor readings.

If you were running this from an MSW type AC inverter, then I would check and make sure that the power supply (isolation transformer, etc.) are not overheating (the sharp MSW edges can create excessive current spikes in the diode rectifier/capacitor charging circuit).

In general, utilities only charge residential power users for kWH, not kVA--So you will not see excessive power charges either (this is obviously, a relatively small power draw).

-Bill

waynefromnscanada · February 2013

Re: Question about Power Factor

Agree with the others, extremely unlikely any problem, just the way the power supply was designed, no big deal at those low power levels. Low PF would not be a warranty issue with something like this. If it works and doesn't smoke, the manufacturer considers his or her job done. Not only that, but the vast majority of folks handling warranty or sales issues, have never even heard of PF.

Cariboocoot · February 2013

Re: Question about Power Factor

I have a few of these kicking around. Never thought to measure them because I don't use them (they get dirty faster than you can clean them). But most have a fan to move air through and a transformer to produce the high Voltage for ionization. That's two variable induction loads. Not surprising the PF is bad on them.

I'll have to see if I can find even one of them and see what it says. Finding things around here ... Well I'm thinking of naming the place "The Haystack".

BB. · February 2013

Re: Question about Power Factor

I believe that some/many/all (?) of these small ion generators are using Cocckroft-Walton ladders to generate the high voltage DC (at very low current and not great power factor):

http://en.wikipedia.org/wiki/Cockcroft–Walton_generator

http://homemadecircuitsandschematics.blogspot.com/2012/08/make-room-air-ionizer-circuit-get.html

Unless you are charging a electrostatic filter assembly, every one of these I have seen just ends up blackening the walls because the charged dust has to go "somewhere" (usually, the dirt does not clean up very easily either).

-Bill

Cariboocoot · February 2013

Re: Question about Power Factor

Good point, Bill; the ones I've got are either electrostatic filter or HEPA filter + ionizer.

Still worth a look at the power figures.

Now, where did I put my meter?

Question about Power Factor

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