On Tuesday, May 9, 2017 at 12:19:18 PM UTC-7, gyans...@gmail.com wrote:> Talked to a motor manufacturer in Germany.> They don't even do DC motors any more, no call for > them at all. Just ac and brushless DC which is really > ac under a different name. Apparently with a good ac > controller you can get an induction motor to have the > same torque as a DC motor and you get max torque at > zero speed - all down to flux vectoring. So do we throw > out our brushed motors.There is a light rail system, a few years old now, in Seattle. If you are anywhere near the train, with an AM radio, you know that the train is running. The power converter puts out enough harmonics within the AM band, which then go down the overhead wires to any nearby radios (usually in cars). We also have some electric trolley (two overhead wire) buses in Seattle, with different converter technology, that also goes into the AM band. As far as I know AC/DC motors (series wound) are still used in many household appliances, still cheaper than the appropriate power converter. For tiny motors, like for battery powered toys, I believe that they are usual DC brush motors.
So DC motors are obsolete!
Started by ●May 9, 2017
Reply by ●July 18, 20172017-07-18
Reply by ●November 16, 20222022-11-16
eric.jacobsen@ieee.org wrote:> On Fri, 12 May 2017 13:56:50 -0500, Tim Wescott > <tim@seemywebsite.really> wrote: > >> On Fri, 12 May 2017 11:09:26 -0400, Randy Yates wrote: >> >>> Tim Wescott <seemywebsite@myfooter.really> writes: >>>> [...] >>>> I think that itty bitty brushed motors will be around for a while, at >>>> least until people figure out how to make itty bitty controllers that >>>> are cheaper than itty bitty brushes and commutators. >>> >>> Too funny! Tim, was the term "itty bitty" used in your graduate >>> textbooks? >> >> No. But it should have been. >> >> I couple of decades ago I realized, thanks to a colleague with a PhD, >> that "bazzilion", "ginormous", "teeny", etc., are all valid technical >> terms (meaning, in order, roughly, and in most contexcts, "so many that >> it's not cost effective to enumerate", "so big that it's not cost >> effective to consider the size", and "so small that it's not cost >> effective to consider the size"). >> > > There are measurement units that are commonly used to convey similar > meaning, .e.g., "buttloads", "shit-ton", etc. I've accepted these, > and many other, as legitimate technical terms or units of measurement > for a long time. They seem to be nearly universally accepted, so it > has been neither problematic nor controversial in my experience.Remember Mars Climate Orbiter and the Gimli Glider. You have to specify if it's a metric buttload or an avordupois buttload. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
