Hi peter
Very interesting question and perhaps the fellow from excel tech could help.
First the current limits from an inverter is for total current, both reactive
and in phase. But the starting and running currents for motors are from both
reactive and in phase current. Is the reactive current large on motor
starting? I expect the reactive current is small on start surge. On running
however the reactive current depends upon load.
Some one know?
Darryl
--- On Mon, 8/25/08, Peter Parrish [EMAIL PROTECTED] wrote:
From: Peter Parrish [EMAIL PROTECTED]
Subject: Re: [RE-wrenches] Power-Save and Power Works
To: [EMAIL PROTECTED], 'RE-wrenches' re-wrenches@lists.re-wrenches.org
Date: Monday, August 25, 2008, 10:14 AM
This is a pretty important measurement. I was hoping that
the Power-Save was
eliminating the out-of-phase current, leaving only the
in-phase component.
But if it throttling down the in-phase current as well,
that's another
story. It would be nice to know the Power Factor in both
cases, which would
answer the question.
Let's assume for a moment that the Power-Phase does
eliminate the
out-of-phase current, but not the in-phase current.The
immediate question
that comes to my mind is Are the current specs for an
inverter (continuous
and surge) based on in-phase current or the total current,
part of which is
in phase and part out of phase? I suspect it is the
latter (total current).
In which case the Power Phase (or its equivalent) would be
useful in
presenting lower (motor based) surge currents to an
inverter.
Another question that I have thought about every since I
bought my first
Kill-a-Watt, Is there a similar version for 240V
loads? I suspect that one
could kludge two 120V Kill-a-Watts together in a j-box and
make it work some
how, but a real 240V version at a reasonable price would be
great news.
- Peter
Peter T. Parrish, [EMAIL PROTECTED]
_
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On
Behalf Of Jeff Yago
Sent: Sunday, August 24, 2008 8:56 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Power-Save and Power Works
On start up, the A/C unit went up to 91 amps and leveled
out at 13 without
the Power-Save 1200 on. When the Power Save unit was
engaged it was a draw
of 35 amps and leveled out at 8.75. That pretty much blew
everyone away!
After that, I tested everything with a motor load in my
house. I was
astonished at the significant reduction in amperage.
- - - - - - - - - - - - - - - - - - - - - - - - -
You note they are not measuring the output of the device
being connected.
For example, they are reducing the current draw of the
motor in the AC unit
by slowing it down a little, which will reduce the cooling
output by same
percentage. Like a variable-speed-motor drive, yes you can
reduce the motor
current draw, but you are also slowing down the fan, pump,
or compressor it
is driving. Only time this may be an advantage is if you
want to reduce the
output of the device being driven as part of redicing its
current draw.
Jeff Yago
_
Netscape. Just the Net You Need.
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