KAW Question

I have noticed that the Kill-A-Watt and the Seasonic PowerAngel are identical and was wondering if anyone has more information.
Exhibit A the KAW: http://www.p3international.com/products/special/P4400/P4400-CE.html Exhibit B PowerAngel: http://www.seasonicusa.com/products.php?lineId=8

On Fri, 28 Apr 2006 21:11:24 GMT, "Daniel Armstrong" wrote:

I have noticed that the Kill-A-Watt and the Seasonic PowerAngel are identical and was wondering if anyone has more information.
Exhibit A the KAW: http://www.p3international.com/products/special/P4400/P4400-CE.html Exhibit B PowerAngel: http://www.seasonicusa.com/products.php?lineId=8

Just guessing. The KAW is made in Taiwan. The other one is probably the chinese knockoff.
I've compared both my KAWs to a laboratory standard and both are quite accurate. No knowledge of the knockoff.
If you need more functionality including battery backup and higher power handling capability, then I recommend the Watts Up line.
John --- John De Armond See my website for my current email address http://www.johngsbbq.com Cleveland, Occupied TN Don't let your schooling interfere with your education-Mark Twain

Neon John wrote:

I've compared both my KAWs to a laboratory standard and both are quite accurate. No knowledge of the knockoff.

I've heard others say it depends on the waveform, with it being way off with some loads. Not tested them myself though.
NT

In article , no@never.com says...

On Fri, 28 Apr 2006 21:11:24 GMT, "Daniel Armstrong" danielthechskid@mchsi.com> wrote:
I have noticed that the Kill-A-Watt and the Seasonic PowerAngel are identical and was wondering if anyone has more information.
Exhibit A the KAW: http://www.p3international.com/products/special/P4400/P4400-CE.html Exhibit B PowerAngel: http://www.seasonicusa.com/products.php?lineId=8
Just guessing. The KAW is made in Taiwan. The other one is probably the chinese knockoff.
I've compared both my KAWs to a laboratory standard and both are quite accurate. No knowledge of the knockoff.
If you need more functionality including battery backup and higher power handling capability, then I recommend the Watts Up line.
John --- John De Armond See my website for my current email address http://www.johngsbbq.com Cleveland, Occupied TN Don't let your schooling interfere with your education-Mark Twain

Hello John, I own a Valhalla power analyzer, Kill-A-Watt and (had) a Watts Up Pro. The Valhalla power analyzer cost $1,100 ish new and this is what I used as a reference. The Kill-A-Watt consistently read close to the reference. It is an impressive meter for $35 shipped.
The "Watts Up" line is available in three models and the higher two models have computer interfacing capability but I believe the sensing assembly are the same across all three modoels. The Watts Up is within the specified accuracy using a truly resistive load, such as a lightbulb, but two different Watts Up units from different lots I've owned did not handle inductive loads well at all. They both showed a level of error well in excess of the specifications, in fact to quite an unacceptable level in my opinion. The first unit I owned read high and was outside the guaranteed accuracy, so I sent in for a replacement. The replacement read 20% low.
Just where might you encounter a non-unity inductive loads? Basically, anything with an induction motor, such as: refrigerators, a window air conditioners, fans, among other things. The merit of an AC power meter over a simple ammeter is the ability to measure the real power of non- unity and non-sinusoidal loads, which my samples of Watts Up didn't do well. Both units have been returned to the manufacturer and they have been able to reproduce the problem, but they're not able to provide a they can guarantee to meet the instrument's original specifications, therefore, I don't believe this is an isolated incident affecting only my two units.
If you happen to own a Watts Up meter and you have a reference meter, you should compare the readings on them using an induction motor as the load. If you don't have a reference meter, connect a bank of motor start capacitors. The volt ampere value (voltage x ampere) should be quite substantial while the wattage reading should be negligle as the voltage and current phase are almost 90 degrees out of phase. If you get a substantial wattage reading, your Watts Up too suffer from phase error.

On Wed, 10 May 2006 16:25:36 -0700, ITSME.ULTIMATE wrote:

If you happen to own a Watts Up meter and you have a reference meter, you should compare the readings on them using an induction motor as the load. If you don't have a reference meter, connect a bank of motor start capacitors. The volt ampere value (voltage x ampere) should be quite substantial while the wattage reading should be negligle as the voltage and current phase are almost 90 degrees out of phase. If you get a substantial wattage reading, your Watts Up too suffer from phase error.

Yes, I have a watthour meter calibration bench that I maintain traceable. My old Watts Up did fine down to 0.5pf. I haven't checked any lower.
The two I just bought (pro and pro es) have a different "feel" which means the firmware is significantly different.
I haven't had time to check them but I will before using them for customer (paying) work. I did notice that the Pro behaved quite funny when connected to my washing machine. The skeletal motor in the thing is a low PF load and the PF varies widely over each agitator cycle. The PF indication was all over the place. I need to hook the Pro ES up and do a datalog to see what is happening.
I'll followup when I get more data.
John
John --- John De Armond See my website for my current email address http://www.johngsbbq.com Cleveland, Occupied TN Don't let your schooling interfere with your education-Mark Twain

In article , no@never.com says...

On Wed, 10 May 2006 16:25:36 -0700, ITSME.ULTIMATE itsme.ultimate@gmPINKail.com> wrote:
If you happen to own a Watts Up meter and you have a reference meter, you should compare the readings on them using an induction motor as the load. If you don't have a reference meter, connect a bank of motor start capacitors. The volt ampere value (voltage x ampere) should be quite substantial while the wattage reading should be negligle as the voltage and current phase are almost 90 degrees out of phase. If you get a substantial wattage reading, your Watts Up too suffer from phase error.
Yes, I have a watthour meter calibration bench that I maintain traceable. My old Watts Up did fine down to 0.5pf. I haven't checked any lower.

What type of power factor? My watts up doesn't seem to be as off with distortional power factor loss, such as switch mode power supply and greatest with cos theta displacement power factor, such as an inductor.
Computer power supplies can easily get around 0.5PF.
"did fine" defined as the meter did not deviate outside of stated accuracy?

The two I just bought (pro and pro es) have a different "feel" which means the firmware is significantly different.
I haven't had time to check them but I will before using them for customer (paying) work. I did notice that the Pro behaved quite funny when connected to my washing machine. The skeletal motor in the thing is a low PF load and the PF varies widely over each agitator cycle.

It's normal for AC motor to vary in power factor with changing load (in this case, accelearting the impeller against water.