We are really fish out of water with this question. There are so many effects to be considered, such as the I**2*R drop of overhead wires, motor efficiencies, resistive characteristics of light bulb filaments .... The way I see it, everybody's posting on the subject (whether lowering AC distribution voltage would result in less power draw) has had a bit of truth and a bit of un-truth.
For instance, when considering motor efficiency. Lowering the voltage to a motor optimized for standard AC line voltages will cause it to run less efficiently. It still may draw less power. But, what if the motor is doing work such as drilling a hole or cooling a room? It will be operated at lower power for a longer time (after all, it still has to drill the same hole, or cool the same room) with lower efficiency. So when you calculate the energy used (after all, we get charged for energy, not power) the motor will use more total energy. And, its useable lifetime will be reduced. Which will increase the manufacturing rate of motors and the energy used to manufacture motors ... We are dealing with a complex issue here. Even light bulb filaments have non-trivial resistance characteristics. Devices operating from switching power supplies may or may not draw less power from less voltage, depending upon what line voltage they were optimized for. I know enough about this subject to know that we don't know enough to state answers with any known certainty. (say that 5 times fast for your kids when you get home tonight :-) Chris Maxwell Design Engineer NetTest 6 Rhoads Drive, Building 4 Utica,NY 13502 email: chris.maxw...@gnnettest.com phone: 315-266-5128 fax: 315-797-8024 > -----Original Message----- > From: geor...@lexmark.com [SMTP:geor...@lexmark.com] > Sent: Thursday, May 10, 2001 9:34 AM > To: emc-p...@ieee.org > Subject: Voltage vs. Power > > > > > Some posts seemed to suggest that lowering the distribution voltage > could cause the power to increase. I doubt this can occur, as it would > require a new basic device with operating characteristics opposite that > of a resistor. As one posted noted, power = V**2 / R. So, as V > decreases, > R would have to decrease rather rapidly for the input power to remain the > same or increase. > > It is true that most heavy RLC loads would operate less efficiently at > less > than intended voltages, but the power would still be less. I doubt the > efficiency would fall greatly at 5% or so reduction in nominal line > voltage. > > Merely my personal opinions................. > > George > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: pstc_ad...@garretson.org > Dave Heald davehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
