Interesting from a production point of view. If they have a need for low quantities (relative) of motors with different HP then it might make sense to tools once and then be able to vary the characteristics during assembly. I was thinking it might be more interesting if they put the rotor on a lead screw and allowed the positioning of the magnets w.r.t. the coils to be adjusted. Would provide something like field weakening on a permanent magnet motor.
Regards, Lawrence Harris [email protected] > On Jan 4, 2018, at 15:09, ROBERT via EV <[email protected]> wrote: > > I do not see the advantage except having the capability to use one motor core > for multiply HP motors. Does anyone think GM is going to use different > magnet lengths in the same motor? Does this have some efficiency > improvement? Do you think they are going modify the controller to allow > different magnet lengths in the same motor? Anyone have any thoughts on this > subject? > > > ________________________________ > From: EV <[email protected]> on behalf of brucedp5 via EV > <[email protected]> > Sent: Thursday, January 4, 2018 2:43 PM > To: [email protected] > Cc: brucedp5 > Subject: [EVDL] EVLN: GM's Multiple-Magnet-Length Electric-Motor Patent > > Anyone who thinks General Motors isn’t serious about electric vehicle > leadership doesn’t have a clue. > > Despite Silicon Valley’s derogatory ideology regarding conventional car > companies like General Motors, the dinosaur from Detroit has been at the > forefront of electrifying personal mobility. GM’s flirtation with electric > vehicles began in earnest back the early ’60s. It started with the > Electro-Vair and Electro-Maro programs in the ’60s, then came a > battery-powered Chevette in 1977, followed by production of the EV1 in the > late ’90s, before culminating with the Chevrolet Bolt, the industry’s first > long-range-yet-affordable-mainstream-electric-car. > > But the company isn’t resting on its laurels, as Tesla Model 3 reviews begin > to hit the internet, GM is busy working on a new family of electric cars due > in 2021. While advancements in battery technology have long been heralded as > the key to consumer adoption, GM engineers haven’t forgotten that a motor is > still what propels a vehicle forward, electric or not. > > Published on December 19, 2017, by the USPTO, GM has filed a patent for an > electric motor with multiple magnet lengths which could totally change how > the company thinks about manufacturing electric propulsion systems. > > For example, the Chevrolet Bolt uses a permanent magnet brushless motor, > where a magnetic field is produced by the spinning magnet and rotor assembly > which then transfers to the stator core and interacts with flowing current > to create torque. Differing magnet lengths will change the torque output, > smaller magnets decrease torque, while longer ones increase torque, > proportionally. > > What the company is proposing is a new “modular” lamination sheet which > would be capable of accepting multiple magnet lengths. Instead of being > forced to re-engineer the lamination stack each time a change in magnet > length is required, GM proposes a series of tabs within the apertures of the > lamination sheets which, when layered, can be assembled to delineate the > magnet slots. > > Effectively, the tabs will allow the stacks to accept either short or long > magnets–the tab will support the shorter magnet halfway down the aperture or > get pushed out of the way upon inserting a longer magnet. GM claims there > will be at least a 25-percent difference in magnet lengths. > > It’s helpful to think about GM’s work with modular lamination stacks almost > like powertrain sharing–take GM’s naturally-aspirated 6.2-liter small-block > V8, which is offered in LT1 and L86 guise. As the high-performance version, > the LT1 is equipped with a shorter intake runner for better high-rpm > breathing, different exhaust manifolds, and unique cam timing; while the > trucks make use of longer intake runners in order to fatten up the mid-range > torque curve. > > What will be of interest moving forward is how GM plans to implement the > respective magnet lengths, will the smaller magnets be used for efficiency, > while the bigger ones left for high-performance or hauling? Possibly, but > there are also drawbacks to simply increasing magnet size; larger magnets > may create more torque, but they also force the coil to fight through more > resistance as the higher torque values lead to an increase in eddy and > hysteresis. > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180104/7d69000d/attachment.html> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180104/a1f14574/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
