ErnieHorning Posted March 12, 2013 Share Posted March 12, 2013 How accurate is the Kill-O-Watt anyway. Well seeing that I have access to some very expensive electronics test equipment and I was working on a project that required similar tests; I took advantage of the situation and tested the Kill-O-Watt also.The results were that the Kill-O-Watt is an extremely accurate piece of test equipment. The resistive watts measurement was made by paralleling various light bulbs and heater elements and varying the input voltage with a VARIAC. Everything was mounted on a wooden wall to keep the high voltage still and provide plenty of heat dissipation to the air. The wire between bulb sockets was 10 gauge and was left bare to provide cooling and to keep the wire resistance from changing very much.The values that you see in the chart are where the measurement unit was slowly increased until the measured value was reached. The value displayed on the Kill-O-Watt was then recorded.I was doing this test while connected to a 20 amp circuit, so I had plenty of headroom. But let me tell you, 1800 watts of heat is pretty amazing to experience. You’re just under the pain threshold at about 3 feet away.“I do these things so you don't have to.” - Glenn Sessoms (Texhoma Glenn)Kill-O-Watt Accuracy.pdf Link to comment Share on other sites More sharing options...
WilliamS Posted March 12, 2013 Share Posted March 12, 2013 Great write up, great tool for the guys still using a lot of blow molds, spot lights, or incans. Even the pixel guys with AC/DC power supplies need to watch how much load the pull at full power. Link to comment Share on other sites More sharing options...
MCas4380 Posted March 12, 2013 Share Posted March 12, 2013 That is really reasuring to know that my Kil-o-watt is that close Link to comment Share on other sites More sharing options...
George Simmons Posted March 12, 2013 Share Posted March 12, 2013 I've wondered that myself after seeing 4 watts and .06 amps on my KOW's readout with nothing plugged in. This is the second one I've had that's done this. I guess my question boils down to what should I regard that bogus reading to be? Is it a baseline that needs to be added to whatever I plug in to measure, or is it an artifact of good old Chinese technology to be ridiculed and then ignored? Link to comment Share on other sites More sharing options...
WilliamS Posted March 12, 2013 Share Posted March 12, 2013 I've wondered that myself after seeing 4 watts and .06 amps on my KOW's readout with nothing plugged in. This is the second one I've had that's done this. I guess my question boils down to what should I regard that bogus reading to be? Is it a baseline that needs to be added to whatever I plug in to measure, or is it an artifact of good old Chinese technology to be ridiculed and then ignored? Just a shot in the dark on this one, as any of the electricians may know this better. Would that load be from the KOW itself on that circuit. I never thought about it but is it taking in account for itself? Link to comment Share on other sites More sharing options...
ErnieHorning Posted March 13, 2013 Author Share Posted March 13, 2013 I didn’t spend any time on investigating the lowest measurement. This was a 40 watt bulb with the VARIAC setto the minimum. I didn’t investigate down that low; I didn’t know anyone would care. 4 watts is only 30 mA and on a device that can measure up to 15 amps without auto ranging; I was surprised that the KOW was this accurate. The KOW does not measure itself. It only measure the current passing through the outlet hot terminal. I don’t remember the exact value but the KOW does draw about 60 mA from the line. Link to comment Share on other sites More sharing options...
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