To All,
the word from my local utility here in NY is residential meters are
just real power (Watts). For large commercial accounts they do measure the
reactive power as well (VARs). Hope this helps.
Chris Schaefer
Solar and Wind FX Inc.
5115 South Hill Road
Canandaigua(Bristol Center) New York 14424
585.229.2083
Cell 748.1870
[EMAIL PROTECTED]
http://www.solarandwindfx.com/
Where Knowledge Equals Power Independence
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Dan,
Glad you brought up reactive vs real power. I was under the impression
that most residential meters measured apparent power not real power.
Based on your description:
If the utility meter measures apparent power the power save will likely
reduce the customers bills by ensuring that the apparent power matches
the real power used.
If the utility meter measures real power then it wont have any affect.
Sky Sims
Ecological Systems
http://www.ecologicalsystems.biz
220 County Road 522
Manalapan, NJ 07726
732-462-3858 toll free)866-759-7652 fax)732-462-3962
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Exeltech
Sent: Saturday, August 23, 2008 4:31 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Power-Save and Power Works
A reply from a power engineer's perspective:
The "Power-Save" device contains only an AC capacitor. Nothing more.
I've had them in my hands, looked inside, and even used lab-grade
equipment to evaluate their effectiveness - or not.
When connected to an AC power circuit, all a Power-Save does is provide
varying amounts power factor correction when inductive loads are in use
(depending on the load). It does not, and can not reduce "real power"
consumed.
Prove it to yourself. Put a Kill-A-Watt meter or Watts Up meter in line
with an inductive appliance. With the appliance running, set the meter
to read actual watts, and record the value.
Next, change the wattmeter to read volt-amps and record the value. If
you're using a wattmeter capable of reading power factor, measure and
record that as well. With reactive loads (e.g. motors), the V-A value
will ALWAYS be higher than actual watts. How much higher depends on the
motor (among other things).
Then, put the Power-Save into the circuit. If you're lucky, the
capacitor will balance out some of the inductance in the circuit caused
by the appliance, and the measured volt-amps reading will decrease from
the previous reading. The power factor will also improve (get closer to
a value of 1.0). However, if you check the *real* power being consumed
with the Power-Save connected, you'll find the wattage hasn't changed.
Ray saw no change because he was monitoring real watts.
The allegation in the ad of a "big" change is either because they were
monitoring reactive power (volt-amps) in the demonstration.
Compressor surge watts will be different every time the appliance turns
on. The surge peak depends on a variety of variables, such as the AC
voltage at the moment the compressor turns on (are we at a peak or
zero?) .. the head pressure at that instant .. the type and age of the
compressor .. the position of the piston relative to a compression
stroke, and so forth.
As to the "testimonial" .. who knows? I recall seeing anti-aging skin
creams refuted recently, where doctors gave on-screen endorsements of
the product, then later admitted under oath they'd never touched the
very product they were endorsing.
I've also met electrical engineers who didn't know the difference
between watts and volt-amps. Perhaps this was another, if in fact the
endorsement is even legit.
The power company will like it if you improve your power factor, but you
won't see any measurable reduction in power consumption resulting from
the use of this device.
So why do they sell it? Something about "one born every minute" comes
to mind.
Regards to all....
Dan
Sr. Engineer
Exeltech
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