ECN Forum Forums General Topics of the Trade General Discussion Area More snake oil?

Agreed. I guess my post was not clear enough. A residence is full with equipment that have potential pf issues. Anything with a motor, ballast, or transformer is a candidate. It all comes down to how often you use them. For example in my hose right now, I have a flourescent light on (ballast) the frige is cycling and my lap top is running off it power unit (transformer). All my electronis have a little transformer in them and a couple of motors. Seperatly they do not amount to much. Combined, they could add up. In hot areas, you have fans and AC running all day. Colder areas you have blowers and fuel pumps running. It is dependent on on what you got and how often you use it.

I personally find it hard to believe that a 10% savings is possible on a residence unless you have a mansion or you are just running a bunch of electrical equipment all the time. If residential pf correction was cost effective or profitable, the POCO's would be all over it.

IIRC, a residential kilowatthour meter measures only real power consumption, and ignores reactive power (the inductive or capacitive current draw). So a homeowner won't see any difference on the electric bill. The POCOs just figure that residences have about the same power factor, and it's just figured into the rates they charge.

Yep, exactly.

So NONE of these devices are going to save the homeowner one single cent!

Interestingly, the units nameplate says "7-amps" @ 240-volts".
I put a meter on the main and the current dropped 6 amps when the unit was turned off.
The branch breaker feeding the unit did the same thing.
My question is...

Is this thing actually consuming 1440 watts, or am I measuring 6 amps of capacitive current from the unit charging and discharging back into the line?
If so, what is the net consumption of the unit, if anything at all?

Thanks,

John

You'd know it if that was consuming 1440 watts, it'd be making a lot of heat. Burning up, almost. It's just charging and discharging back to the line, as you said in the 2nd half of your question.

POCOs don't like it when you draw current without consuming real power, it means that they have to have heavier wire and transformers without selling more energy.

Industrial users sometimes have, as part of the metering, a measurement of reactive power, as well as real power. That reactive power is usually inductive (motors and florescent light ballasts) and adding capacitors to that reduces that reactive power seen by the POCO's reactive power measurement. That's where money would be saved. Most homeowners don't have reactive power measured by the POCO, so they would not save any money with this thing. The POCO won't mind someone volunteering to reduce their reactive loading; they just won't know who is doing that (and how much) to be able to offer any money savings.

On a different aspect of the topic: looking at the cap banks on aerial distribution primary lines, I'm surprised by how many have one or two of the three cutouts open, and have been in that state for quite a while.

Since not all of the cutouts are open, I'm assuming the openings are due to fuses blowing rather than intentional switching operations (i.e. I don't *think* cap switching is done on a phase-by-phase basis). This would imply that keeping the caps operational is a relatively low priority.

The 1950s seemed to be the heyday of automated primary capacitor switching, with controllers activated by time, temperature, voltage, current, remote signals, alignment of the planets, etc. in any imaginable combination. That's probably still true for substation caps, but out on the lines around here, all I see is manual switching.