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#68729 - 08/15/06 05:00 AM How to Measure Power Factor
rhpope Offline
Member
Registered: 02/23/06
Posts: 18
Loc: North Carolina
How do you measure power factor and what do you measure it with. Is there some type of hand held meter that can be used to measure watts as I am told this is really what you are looking for and trying to reduce?

Thanks,
Roger
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#68730 - 08/15/06 10:28 AM Re: How to Measure Power Factor
John Crighton Offline
Member
Registered: 05/16/05
Posts: 177
Loc: Southern California
I assume you're asking about a meter for small appliances that plug into 120 V receptacles. Fortunately, there's a really neat meter for the purpose, and it's less than $25.

Froogle "kill-a-watt" -- you can't miss it.

It's a digital meter that measures RMS voltage and current, frequency, power, power factor, and VA, and it's become an indispensable part of my tool kit.
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#68731 - 08/15/06 11:49 AM Re: How to Measure Power Factor
derater Offline
Member
Registered: 03/30/02
Posts: 179
Hey, John what model do you have, do they vary in options/ performance? Froogle? I thought you were kidding!!
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#68732 - 08/15/06 01:04 PM Re: How to Measure Power Factor
John Crighton Offline
Member
Registered: 05/16/05
Posts: 177
Loc: Southern California
I'm pretty sure there's only one model, the P4400. Here's the manufacturer's web page for it.

They make great gifts for gadget geeks!
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#68733 - 08/15/06 01:27 PM Re: How to Measure Power Factor
Dnkldorf Offline
Member
Registered: 12/12/04
Posts: 1064
Loc: nowhere usa
Roger,

What exactly are you looking to measure, or is your question in general about PF?
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#68734 - 08/16/06 03:57 AM Re: How to Measure Power Factor
rhpope Offline
Member
Registered: 02/23/06
Posts: 18
Loc: North Carolina
The power factor question is related to a Rotary Phase Converter. I am trying to reduce the converters power consumption to the least possible amount. I just wanted to know how to measure the power draw from the two single phase legs on the input side so that is necessary I can add capacitance between these two legs to get the power factor closer to 0.9. Everything that I have been read is that a Rotary Phase Converter produces a bad power factor.

Roger
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#68735 - 08/16/06 07:14 AM Re: How to Measure Power Factor
renosteinke Offline
Cat Servant
Member
Registered: 01/22/05
Posts: 5316
Loc: Blue Collar Country
First of all...the "Kill-a-watt" is sold in the ECN store!

Power factor, simply put, is the difference between "watts" and "kva."

If you have a steady load, you can get a good idea by comparing the meter reading to whay you get when you measure volts, measure amps, and multiply the result. This is one of those times you want to have "true RMS' type meters!
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#68736 - 08/16/06 07:50 AM Re: How to Measure Power Factor
Dnkldorf Offline
Member
Registered: 12/12/04
Posts: 1064
Loc: nowhere usa
Roger, count me in on this one. I want to see you get through it, and learn with you if you don't mind.


Give us the motor size and readings, and we can walk you through it, and all learn something together.

Radar??
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#68737 - 09/12/06 10:40 AM Re: How to Measure Power Factor
Almost Fried Offline
Member
Registered: 09/04/06
Posts: 98
Loc: Madison County, Ark. USA
rhpope, what did you ever do about this concern?
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#68738 - 09/14/06 09:56 AM Re: How to Measure Power Factor
Trumpy Offline


Member
Registered: 07/05/02
Posts: 8211
Loc: SI,New Zealand
Reno is quite right here.
Power factor is the ratio of useful power(VxI) to useless (Wattless) power in a circuit or even an entire installation.
To a degree, the lower the wattless component, the higher the power factor.
It is about using the most from what you have supplied to you.
We had a dedicated PF meter at the PoCo, but I can't at this moment remember how it was wired.
What's even more scary, is the fact that I built the thing in the first place.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin
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