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.
So DC motors are obsolete!
Started by ●May 9, 2017
Reply by ●May 9, 20172017-05-09
Reply by ●May 9, 20172017-05-09
On Tue, 09 May 2017 12:19:15 -0700, gyansorova 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.Keep what you have, at least. They'll work as well as they ever did. 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. Industrial brushless motors with built-in controllers are getting more common -- one box with a shaft on one end and a cord on the other. Give it power and commands, and it does what it's told. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work -- see my website!
Reply by ●May 10, 20172017-05-10
On 05/10/2017 03:19 AM, gyansorova@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. >Brushed motors are still being used in massive numbers in new product designs. For example, most new power tools and kitchen appliances still use them. It isn't high cost German manufacturers who produce those low end motors, though. Steve
Reply by ●May 10, 20172017-05-10
On Tue, 09 May 2017 12:19:15 -0700, gyansorova 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.We use some specialty "zero-cogging" motors to generate precision torque-systems - "manipulanda". These are grasped by the hand, and the user attempts to move the device while following a kind of video game. Unfortunately variations in torque - particularly at higher frequencies - excite certain proprioceptors in a bad way. We need super-smoothness as well as being able to deliver high torque perturbations. So yes, it's a _real_ niche application, but the loss of these motors is gonna be hard. There is at least one maker of a fractional-turn motor that is close to working (we haven't had to go there yet).
Reply by ●May 12, 20172017-05-12
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? -- Randy Yates, Embedded Firmware Developer Garner Underground, Inc. 866-260-9040, x3901 http://www.garnerundergroundinc.com
Reply by ●May 12, 20172017-05-12
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"). -- www.wescottdesign.com
Reply by ●May 12, 20172017-05-12
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. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●May 13, 20172017-05-13
On 5/12/2017 5:23 PM, 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.You need to be more specific. Is that an imperial "shit-ton" or a metric "shit-ton". The imperial "shit-ton" is an informal unit with a definition that varies with the speaker much like the inch being related to the distance between the user's knuckles. -- Rick C
Reply by ●May 15, 20172017-05-15
On Friday, May 12, 2017 at 5:23:34 PM UTC-4, eric.j...@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.milli-smidgen .
