Dan, Glad you brought up reactive vs real power. I was under the impression that most residential meters measured apparent power not real power.
Based on your description: If the utility meter measures apparent power the power save will likely reduce the customers bills by ensuring that the apparent power matches the real power used. If the utility meter measures real power then it wont have any affect. Sky Sims Ecological Systems http://www.ecologicalsystems.biz 220 County Road 522 Manalapan, NJ 07726 732-462-3858 toll free)866-759-7652 fax)732-462-3962 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Exeltech Sent: Saturday, August 23, 2008 4:31 PM To: RE-wrenches Subject: Re: [RE-wrenches] Power-Save and Power Works 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 _______________________________________________ List sponsored by Home Power magazine [email protected] http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.6.7/1632 - Release Date: 8/25/2008 7:05 AM _______________________________________________ List sponsored by Home Power magazine [email protected] http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
