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I need a "watt meter" to measure consumption of my home applicances - Page 2

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Posted by Spud on July 26, 2006, 5:03 pm

NeXTstep wrote:


25 euro

Posted by Neon John on July 26, 2006, 5:49 pm

An actual power company type electric meter is hard to beat.


You'll have to figure out a source in your country.  Over here,
they're available surplus for under $0 typically, and some power
companies will sell a new, calibrated meter for only a little more.

A watt-hour meter is by far the most accurate instrument the average
person has access to.  It handles distorted waveforms and low power
factor loads well.  Any in-built error will be the same as the revenue
meter on your house so by definition, the two will closely match.


John De Armond
See my website for my current email address
Cleveland, Occupied TN
Don't let your schooling interfere with your education-Mark Twain

Posted by R L driver on July 26, 2006, 6:14 pm

NeXTstep wrote:

There plug in watt meters that measure voltage , current, pf, watts and
running costs for less than 20 on ebay ... type in "watt meter."
steve the grease

Posted by philkryder on July 27, 2006, 4:37 am

It sounds like there are other things available, but wouldn't a US
Kill-a-watt with appropriate adapter plugs work?

I would expect that:
volts are volts
hz are hz
amps are amps
yes? no? why not?

NeXTstep wrote:

Posted by danny burstein on July 27, 2006, 4:48 am

The KAW is rated for 120 Volts. Messy things might
happen if you try it on the 240 or so volt European standard.

That being said... I risked one of mine on a US circuit
and got unusuable and ridiculous looking displays on it
(no damage, though).

However... I was actually hooked into two legs of
a three phase crcuti, giving me 208VAC and a wierd
wave form, which may have confused it even more.

One of these days, RSN, I'll find a single phase 240V AC
line and plug it into that.

(there are two common ways of getting so-called 220V
in a typical building in the US. Most often you've
got two hot legs that are 120V to neutral, and that
are 180 degrees (out of 360) apart. Hence one leg is,
loosely speaking, "pulling" when the other's "pushing".

If you tap hot<-> neutral you get 120V AC
if you tap hit <-> hot, you get 120_120 $ (which
lots of people call 220. don't ask)...

On the other hand, you can also have a three phase
situaition, wherer you've got three live legs coming
off the transformer (plus neuutral). These are
all 120 degrees apart (that 120 number is purely
conincidentally the same as 120 volts).

If you tap hot <-> neutral, you get the sam 120 VAC

If you tap hot<->hot, you get 120*(sqrt of 3) = 208V AC.
You also get a funky wave form.

Most, but quite definitely NOT all, 240 volt appliances
will work ok at the 208 figure.

(You'd use all three hot wires for a high power item
such as an elevator motor)

Knowledge may be power, but communications is the key
[to foil spammers, my address has been double rot-13 encoded]

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