AlanB
Sierra Vista, AZ
Senior Member
Joined: 11/18/2002
View Profile
 Offline
|
Correcting the power factor will reduce the current flowing in the wiring and reduce resulting heat. This increases overall efficiency.
http://www.allaboutcircuits.com/vol_2/chpt_11/4.html
AlanB
2002 Holiday Rambler Imperial 40PKDD Cummins ISL
|
wa8yxm
Wherever I happen to park
Senior Member
Joined: 07/04/2006
View Profile
 Online
|
I do understand how they work.. And they do work. What I don't know is if they save your money.
People tell me the meter on the outside of the house reads WATTS, If so power factor don't much matter
However if the meter reads VOLT AMPS (And I think it does but frankly have no way of proving it) Then fixing the power factor WILL make a difference
How big a difference depends on how bad the PF is in your house.
Nothin adds excitment like something that is none of your business
Kenwood TS-2000 housed in a 2005 Damon Intruder 377
|
Wayne Dohnal
Banks, OR.
Senior Member
Joined: 03/09/2003
View Profile
Offline
|
I don't think that anybody has been disputing that PF correction reduces losses in the distribution system. The issue is the claim of a lower power bill in a residential application, which isn't going to happen. There will be less loss between the PF correction device and the meter, but it's probably going to be too small to affect the meter reading.
2009 Fleetwood Icon 24A
LinkPro battery monitor
EU2000i generator
|
wa8yxm
Wherever I happen to park
Senior Member
Joined: 07/04/2006
View Profile
Online
|
az99 wrote:So how can I tell which type electric meter I have ? Mine looks like the standard glass dome with a spinning disc.
The DEMAND type has a "dial indicator" (meter with needle) on it and a resettable pointer that indicates peak demand Kind of like some of the water pressure gages they sell for RV use.
Makes it kind of simple
You don' have the Demand type, It is that easy
To the EE who posted about the meters
My question is this. Does the meter on my house multiply volts times amps. (Volt-Amp-Hours) which I believe it does or does it measure Watts as it advertises..
And if it measures watts, How does it compensate for the differnce?
|
stevenal
Newport, OR, USA
Senior Member
Joined: 03/16/2004
View Profile
Offline
|
I'm an EE for an electric utility.
The electro-mechanical meter described measures kWh. There is no compensation or multiplication needed, since only the in phase components of current and voltage work to turn the disc. In the electro-mechanical world, the utility would install a second meter to measure the kVArh, with one of the quantities shifted by 90 degrees. Today, electronic meters are used so a single meter can be used on industrial loads. All meters are ANSI rated at 0.5% or better tolerance.
The mix of loads in a typical residence has a pretty consistent pf. It is more cost effective for all to simply factor that into the rates and not spend the money to meter it. For industrial loads, the pf is far more variable.
It is true that utilities install capacitors in order to improve efficiency. But we are talking about miles of wire. The difference in losses between a pf corrected home and the uncorrected home will be tiny. The improvement will be on the utility side.
Demand metering does not equal kVArh metering. Demand is something else that industrial customers get to have.
The best scams provide you with true statements, and only lie by omission.
'99 Bigfoot 1500
with low loss control on the Fantastic, Dino board on the Dometic.
Torklifts and Fastguns
'04 F350 V10 Crew SRW SB 4X4 6 speed
with tow hook replacement, dual rate charging, Line-X, Timbrens.
|
|
|
az99
N.Y.
Senior Member
Joined: 12/26/2006
View Profile
Offline
|
stevenal wrote:I'm an EE for an electric utility.
The electro-mechanical meter described measures kWh. There is no compensation or multiplication needed, since only the in phase components of current and voltage work to turn the disc. In the electro-mechanical world, the utility would install a second meter to measure the kVArh, with one of the quantities shifted by 90 degrees. Today, electronic meters are used so a single meter can be used on industrial loads. All meters are ANSI rated at 0.5% or better tolerance.
The mix of loads in a typical residence has a pretty consistent pf. It is more cost effective for all to simply factor that into the rates and not spend the money to meter it. For industrial loads, the pf is far more variable.
It is true that utilities install capacitors in order to improve efficiency. But we are talking about miles of wire. The difference in losses between a pf corrected home and the uncorrected home will be tiny. The improvement will be on the utility side.
Demand metering does not equal kVArh metering. Demand is something else that industrial customers get to have.
The best scams provide you with true statements, and only lie by omission. Thanks for your reply. So I guess your saying they these devices do nothing ?
|
az99
N.Y.
Senior Member
Joined: 12/26/2006
View Profile
Offline
|
I wonder how the sales people make the clamp meter show that the motor is drawing less amps when the controller is switched on ?
|
smkettner
Southern California
Senior Member
Joined: 03/21/2005
View Profile
Online
|
Is it really for motors under full load like an air conditioner or is this for motors that are running but waiting for a load such as a table saw or sander?
|
az99
N.Y.
Senior Member
Joined: 12/26/2006
View Profile
Offline
|
smkettner wrote:Is it really for motors under full load like an air conditioner or is this for motors that are running but waiting for a load such as a table saw or sander? It was demonstrated on a 1/2 HP motor running with no load on 110 volts.
|
Wayne Dohnal
Banks, OR.
Senior Member
Joined: 03/09/2003
View Profile
Offline
|
Quote:I wonder how the sales people make the clamp meter show that the motor is drawing less amps when the controller is switched on ? I'll try a guess. When the current is out of phase with the voltage, the motor will need to draw more average current because it's not drawing its peak current at the time of peak voltage. The power draw would be about the same either way. Also, I believe, a motor's power factor will be at its worst when unloaded, so that would be the situation in which to record the most exaggerated data that tells the part of the story the sales person wants to tell.
|
|
|
