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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