David, The standard residential service in the US of A is 120/240 Volts AC.
It is provided by the center tapped secondary winding of the utility transformer. The center tap is grounded and becomes a Neutral such that in the home you have two 120 VAC legs, one from each of two ends of the secondary winding. The two legs are 180 degrees out of phase to each other, and separately are used with the grounded neutral to provide the 120 VAC service. For larger appliances such as stoves, ovens, hot water heaters, clothes dryers and Amateur Amplifiers, the current is sourced by connecting to both 120 VAC legs, resulting in 240 VAC being delivered to the appliance. No additional step-up transformer is required. There is no free lunch. The laws of physics cannot be changed. It is just a different scheme of power delivery which allows a grounded neutral to be carried to each small appliance or lighting fixture. I hope that helps a bit with your understanding. Milt, N5IA -----Original Message----- From: David Dunn Sent: Wednesday, December 14, 2011 3:04 PM To: [email protected] Subject: [Elecraft] Curiosity Only, somewhat off topic. I noted recently several refs by USA users asking about 240 volt ac power plugs etc. Now I have never even been to a 110v country - possibly only USA ? - and I can see a degree of (shock) safety offered with that system, but I can hardly imagine the mass of copper required to carry possibly 200 amps around the house. Nevertheless, I just wondered why there seems such interest in running 240v equipment, presumably via suitable transformer. David VK3DBD/G3SCD. . ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1890 / Virus Database: 2108/4680 - Release Date: 12/14/11 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
