Energy - Power Meters

Wow, I wish I could do that -- I wouldn't have to water-cool my induction coil anymore!

Tim

So it was 2-wire, err single hot? (In the US, all the big stuph would be unmetered if you only looked at neutral...)

The voltage pickoff also powered it?

Did it write to flash periodically, or...?

Yup, the one we did was 240 single-phase.

Small power transformer for that. Nowadays I'd use a switcher.

On powerfail, from capacitive stored power.

John

I came to know it as Audio Shift Keying, related to AFSK (Audio frequent..)

Simple amplitude keying is commonly referred to as "OOK" (On Off Keying) - check Car keyfob IC vendors.

So you do not have central HVAC, refrigerators/freezers, clothes washers, dish washers, or any other motor loads in your house?

The device will not reduce the losses in the motors only the losses in the conductors between it and the meter. (and maybe not even that)

how these devices work is they are advertised at the beginning of a seasonal decrease in power usage so the customer sees a decreasikng usage.

I don't know what "central HVAC" is (so I'd guess that I don't have it). I have the others, but they don't account for a major part of the electricty bill, and the copper losses caused by any reactive component of the current draw (which is all that PFC would save) certaintly isn't significant.

Or do Americans wire their homes with NiChrome?

'Central Heating Ventilation Air Conditioning'

You don't have air conditioning ?:-)

WHAT IS your significant consumer.

...Jim Thompson

Nope. If I did, it would only get switched on for about 5 days a year.

The computers, followed by the kettle. Heating and the cooker are gas, the washing machine does one load per week, I don't need to use a dishwasher for one plate, the microwave only runs for five minutes a day.

Jim; not everyone lives in the middle of the desert...

I'd suspect his fridge.

BTW, another poster commented:

Not quite true; it will cut the I^2R losses in the motor by reducing the current.

I realize I forgot part of the spiel re: the NASA story...

So power needed is a function of load. Ask the water pump to raise 6 gallons per minute 8 feet, and it needs mumble_out watts. Make that 12 gallons & 10 feet; it's bigger mumble watts...true?

Each of the output power needs will be reflected in an input power need of (mumble_out+the losses). And that is I*E*pf, integrated over time.

And: An induction motor's power factor varies with load. The closer it is to full load, the better its power factor.

Mumble_out is fixed *by the load* in everyday apps. Changing a variable must change others so you still get the output.

Say:

Ia * Ea * .8 pf = Ib * Eb * .9 pf

If you improve the PF, and the E is fixed, Ib > Ia. Ergo, Ia^2R > Ib^2R... lower losses in b.

But the alleged way to lower the pf is to lower the pf and you do that by loading the motor to full{er} load. But that's fixed, so you lower the E to improve the PF...but wait, won't that raise I? [Let's not always see the same hands, class...]

And here's the hype.... when demo'ed at county fairs and flea markets; the carnie's display ALWAYS showed an unloaded, free-spinning shaft motor. THAT case could be helped by the Magic box. But in any consumer fridge, or dishwasher, you know Frigidaire or Kenmore or whoever had carefully designed the motor to be fully loaded; they are hardly going to give you more copper and iron than needed, are they? In real uses, as LeRC tested them, it's no better than a wash.

Thankfully ;-)

Remember folks, it's hell-on-wheels out here in Arizona and, with global warming, it'll get worse... so stay away !-)

Probably rents, has steam heat provided. Has no clue that part of his rent pays for that.

I vaguely remember some hype about an AC motor controller that varied its consumption according to load?

Here's one for you... my electric consumption (in kWh) is about 15% lower so far this year than last... looks like global _cooling_ to me ;-)

...Jim Thompson

You don't have to leve in a desert to need AC.

Mine have been dropping for several years. Last month was still under $100.

Just got my water bill. $205, for June.

How much is actually water? Probably lots of "fees" for garbage, etc... taxation without vote :-(

Here in Arizona, my bill is just over 1/2 that.

But my electric bill was $600.73 :-(

...Jim Thompson

I have my own well, so the electric bill covers both.

$141.63. The rest is sewer. Garbage collection fees are on the power bill, yet to come.

I'll be interested to see what that is. It'll be the first one with a full month of AC. I'm hoping AC isn't any more expensive than heat. Can't see why it should be; smaller temperature differential.

Right. Because here, the motor's consumption is basically windage (friction). If you can save just a little of the circuit I^2R losses, that's a big gain in efficiency.

If you save that same number of watts, but the power output is higher, the percent improvement is much smaller.