I've done some searches for MGR's, and have to agree that they're becoming less available. Unfortunately, it seems they stopped making the Highlander somewhere around 2012. I have no idea if Toyota has a similar thing with a different model.
I did find some on the east coast (around New York) mostly listed under Lexus LX400h. Also, I had better luck looking for "differentials" or "differential carriers" particularly for Lexus. Looking for Toyota or Highlander resulted in a lot of garbage.
In general, the Toyota motors use the same control (same amount of poles, same magnetic design, same encoder) It may be possible to get a Prius motor (transmission) for testing purposes or even EV power. A guy in Florida used one to power an MR2:
1991 MR2 + 2004 Prius Transaxle - DIY Electric Car Forums
I'm just not sure how the gearing would work.
Regarding motor testing, I've got a few limitations. The first one is I don't have a 50kW dino.
Another thought - would running the motor at full power for 60 seconds be worthwhile for a car? Seriously - I can't think of a time when I've pushed any of my vehicles at absolute maximum for a full minute. If you look at the accelleration specs for any car, top speed is usually well under 20 seconds. For example the Tesla Roadster reaches 104mph in 12.75 seconds. I seriously wouldn't mind if the controller allowed considerably more power for 10 or 20 seconds, then put a big limit on "continuous" 60 second type power usage.
Would it be possible to test the current-handling capability - not the power - of the stator windings at, say 12V? or perhaps use 120VAC to calculate an RMS AC type power??
- E*clipse
Quote:
Originally Posted by thingstodo
Thanks for the vote of confidence 
Short answer - I can't think of a way to calculate a max current, or a max USEFUL current, I guess. DC current is just V/R but that's not useful in spinning the motor.
A 10 second burst of power will heat things up for sure. Toyota has put a lot of engineering into this unit. In the interest of costs, their controller may not be ABLE to push too much current for longer than the motor can take it. At design time, which was a few years ago, the electronics would have been the most expensive part.
If it were my MGR that was being tested, I would:
- pump in 50 KW for 60 seconds
- run the system at idle and measure the changes in heat for the next hour or until temperatures return to ambient
- pump in 75 KW for 60 seconds
- run at idle and monitor
- repeat every 25 KW on up until you reach a limit.
The limit may be the insulation on the stator, the temperature of the magnets, the smell of varnish being burned off the outside of the housing ...
I have gone through ebay.ca and have not found any MGRs ... perhaps I don't know how to looks very well? |