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View Full Version : Powersave Why don't you have one?



winchman
05-21-2008, 03:33 AM
I know it's a scam, but I'm not sure how it doesn't work.

http://www.power-save.com/product.html

Roger

John Stevenson
05-21-2008, 04:02 AM
If it works on the Capacitor principle then it will work under given circumstances.

I can't comment about a home installation but the piano factory I used to work at had it's own power room with banks of capacitors.

Because induction motors use different amounts of power as they come on load and off load it evens this out.

Our factory had literally 1,000's and that's no exaggeration, of small 1/2 HP to 2 HP motors on the production machines.

Fitting the capacitor banks which were huge, dropped the quarterly bill from about 24,000 UKP to 18,000 UKP

Other far more versed in power correction will be able to explain this better and compare it to the product on sale.

On home scale it may be a scam but in large applications it does work.

.

NickH
05-21-2008, 04:24 AM
I don't have need of one as all my equipment runs on invertor drives and all my flourescent lighting has caps to ballance the chokes, phase change on my suppy is not really a problem.
Might be different if all my stuff ran old single phase motors or I ran a lot of unbalanced inductive loads,
Nick

Evan
05-21-2008, 05:53 AM
It isn't really a scam but the case for it is very overstated as are the potential savings. Where it will save some money is on a single phase motor that is always running below full load. There usually aren't many of those in a household as most motors are sized for the load and only run close to full load when used.

laddy
05-21-2008, 06:56 AM
In Maryland there was a power saving plan you could sign up for with the eletric company. When peak output by the electric company was hit your power was reduced, kinda like a brown out. Friends of ours were on it but not for long. Seemed they were in brown out mode most of the summer and their airconditioning was barely on and lights were dim.

small.planes
05-21-2008, 08:00 AM
I was reading in one of the trade comics I get about a similar looking device which just reduced the incoming voltage to a stabalised 216V (IIRC) the theory being that there would be less current draw, and so less power consumed. I can see the theory, but I dont think it was rated for 100A operation, so no good at my house...

Found it in the mag, its called a VPhase, they create an antiphase signal to reduce the phase voltage :confused: Its only able to handle 2Kw though, so forget running the kettle and the oven and the washer and tumble dryer (thats pretty normal here), even before you run up that 2.5Kw Mill!


Dave

J Tiers
05-21-2008, 08:13 AM
I don't have time to watch the video, which probably is "de-teched" anyway, so I have not the benefit of whatever they let drop in terms of info. It almost HAS to be a capacitor, as that is all that makes much sense per the description.

If indeed it IS a capacitor type deal, it WILL NOT SAVE YOU ANY MONEY as things are now.

Yes, it will reduce the KVARs supplied to your house, but you are actually only CHARGED for KW, not KVARs. That's the way the US meter system works.

So, while it may be a very good and noble, and self-sacrificing thing to do, to spend money to reduce the excess load you put on the power company, it won't pay you back at present.

If at some time that changes, it may be a better deal........

But even then, a capacitor only cancels inductive reactance, reducing the current draw of your load. If you have no inductive items ON (no motors), which is perfectly possible, then it will actually HURT by reversing the net load to CAPACITIVE reactance, similar to, but opposite from the inductive reactance of motors etc.

Large industrial users already often use that system to reduce their loading, but they may be charged extra for reactive loads, or have the Powerco 'fix it" out on the pole.

Not "quite" a scam, but sorta like the old-time airline flight insurance..... generally not worth it.

Laddy: Brown-out (low voltage) mode sounds like a good way to cook all the motors. The Soviets tried it once, and fried most of the motors in the area. Industries often have "drop loads" which are cut off 100% under high load conditions.

Evan
05-21-2008, 08:37 AM
The power company here once offered a plan that reduced your bill at the homeowner level if you had a "shedable" load. The setup was an automatic load shedding switch on the droppable load such as electric heating which would activate when the system voltage fell below a certain value, say 110 volts. They wouldn't allow you to sign up unless you had an alternate source of heat.

lwalker
05-21-2008, 08:57 AM
I believe they do that here too.

We are on the plan that shuts off the A/C temporarily during high load periods. There's an automatic 10% off the bill for the summer months and we never notice the A/C dropout so it's well worth it.



The power company here once offered a plan that reduced your bill at the homeowner level if you had a "shedable" load. The setup was an automatic load shedding switch on the droppable load such as electric heating which would activate when the system voltage fell below a certain value, say 110 volts. They wouldn't allow you to sign up unless you had an alternate source of heat.

A.K. Boomer
05-21-2008, 09:08 AM
What about spike draws on stuff in your house, I thought there was a penalty for having something that drew allot of juice even if for a short period yet i look on my house meter and all I see is the standard spin dials, Does one of them re-set once a month and measure the spike er something or is it only something you find on bigger industrial/business/factory meters?

Also --- could it make sense to have a capacitor bank to cover such a thing?

Evan
05-21-2008, 09:25 AM
The plain old Sangamo style power meter doesn't measure anything except watt hours. Demand meters also have a resettable needle on a separate meter that shows the most power that was drawn during a billing period but that isn't used at the home consumer level, yet.

Don't worry, the power companies have a plan. They are retrofitting all the meters over the next few years to new electronic ones that will present them with a variety of new billing options, none of them cheaper, I'm sure. Businesses will be first but the plan extends to all consumers eventually.


Also --- could it make sense to have a capacitor bank to cover such a thing?

The biggest problem the utilities have now is non-linear loads such as CFL bulbs. Capacitors don't fix that.

The Doctor
05-21-2008, 09:04 PM
First video claims it "filters & recycles excess power". Second video does refer to it as a "capacitor based power conditioner". I'd call both of those stretching the truth. My guess is it's nothing but a fairly small capacitor in a box with no active components at all. They "prove" it warks with a Kill-A-Watt meter and an unloaded motor. If the meter was switched to "watts" instead of current, the truth would be clearly shown.

Checked the price - $299.95:eek: Wow, I gotta start sellin' capacitors!

BTW, the Kill-A-Watt is a usefull little gadget that measures voltage, current, power factor, KVA, & watts. They're great for setting governors & voltage regulators on portable generators, and for use in testing all sorts of electrical devices. Not made by this company though:)

Wanna really reduce your electric bill 25% or more? Turn your thermostat up a few degrees(summer), turn off lights when your not in the room, TV off when not watching, etc.


Ed

J Tiers
05-21-2008, 09:26 PM
The biggest problem the utilities have now is non-linear loads such as CFL bulbs. Capacitors don't fix that.


Actually, they CAN fix that..... partly.

Non-linear loads draw peak currents at certain points in the cycle. With no energy storage locally, that peak is reflected right back out on the line at max amplitude.

A peak charging current like the CFL load draws a short, relatively sharp current pulse as the capacitors in it are charged up to the line peak. That pulse may be a small part of a cycle.

Current is the flow of 'charge", i.e. electrons, very loosely similar to water or air flow in a pipe.

With a local capacitor, some of the electron flow (charge) can come from the capacitor, which is a reservoir of electrons.

That reduces the peak current somewhat, the amount depending on the size of the local capacitor vs the CFL capacitor.

The principle is similar to installing a tank on a long compressed air pipe. That smooths the flow of air, while the capacitor smooths the flow of current.

The effect is not large, and tends to be less the better and lower resistance your wiring is.......

However, I would NOT advise anyone to invest in a "Powersave" device just yet.....

It's primary result will be reducing the amount of money in your account...... NOT reducing your bill as things are now.

The "how it doesn't work" is that it fixes a problem, but one that you are not presently billed for.... So it can't save you money.