[Bowser330]

A 6000 $AUD, 150kw capable controller for use with a 50kw 1000$USD motor??

[AmpEater]

Originally Posted by Bowser330

A 6000 $AUD, 150kw capable controller for use with a 50kw 1000$USD motor??

Price and value are not the same thing

[Sutitan]

Motor is 450 for less than 60 miles away.

However, I cannot justify that controller. Also, a boost converter might cost a bit too, however, if I did consider the AC option, id probably just build a 450v pack

[Olaf-Lampe]

At least it's almost impossible to kill the inverter with such a 'small' load. At peak load it wouldn't draw more than 80A.
Someone should buy one and look inside. It's not easy to disassemble a PM-motor, but maybe he would only need to rewire the coils from serial to parallel or from wye to delta. That would raise kV a lot ( same RPM with less V )
If it's not possible, resell it again
-Olaf

[Bowser330]

Originally Posted by AmpEater

Price and value are not the same thing

I think the use of the toyota differential is creative and a great idea....I just do not see value in under utilizing a 150kw capable controller/inverter for 50kw peak use, but I guess that is just me...

[Ryan800]

I'm new to this so someone should check my logic, but here's how I see it:

For BLDC motors (that's what this is, right?), if the controller can provide enough power, they will make constant torque up to max rpm, so that's where max power will occur.

If one were to use the tritium controller and the motor revs to 10752 at 650 V, then at 450 V, it would rev to 450/650*10752 = 7543 rpm. With 6.86:1 diff and typical tire size, that's 75-80 mph, so more than enough.

Ignoring controller/motor loss, 50kW @ 4610 rpm (3279V) requires 179A because 50,000W/(650V*4610rpm/10752rpm) = 179A. My guess is this is peak power because the batter pack is only 288V so above this, full current can't be supplied... or something. Also, the pack is only rated for 45kW, so it makes sense that it can't keep supplying current beyond about this voltage.

For a sanity check, 50,000W/(4610rpm*2pi/60) = 104N*m (76lb-ft), so pretty close to constant torque all the way from max of 96lb-ft at 0 rpm.

With 180A up to 450V, the motor's power should increase to about 80kW without too much more stress than its OEM application, right? Also, the tritium controller only supplies 300A max so it's not a complete waste, but not a perfect match either. Plus I imagine the motor could be pushed beyond 180A for short periods.


Even if this is correct, this motor/controller/diff combo would only work for a very small car. Max wheel torque would be 96lb-ft*6.86 = 659lb-ft. A Subaru Justy 2wd in 1st gear with the smallest engine available puts up to 804lb-ft to the wheels ignoring losses: 59lb-ft*3.071*4.437 = 804lb-ft. A typical compact car, say a mid 90's impreza, sends to the wheels 110lb-ft*3.785*4.11 = 1711lb-ft.

I don't know what I've decided from all this, maybe just use the diff with a better motor since the size and ratio seem well suited to EMs.

I seem to be on a different page than a few others here, so feedback would be appreciated.

[Ryan800]

Bringing this back to the top... Based on Corbin's thread, I'm optimistic that quite a bit less than max torque will be enough to get up a 5-6% grade as long as the car isn't too heavy. I would also worry about steeper hills in the city since there would be no way to gear down (I live in seattle), but I figure it can probably take a bit more current for short periods than toyota rates it for.

So the point is, I'd be ready to buy this motor/diff and the tritium controller if I had some reasurrance that these figure were in the ballpark. Also, the tritium controller requires 3 hall effect position sensors, could I expect these to be built into the motor? If not can I add them myself? Is there a chance of a 100k NTC thermistor being in the motor somewhere or is there some place I could add one that would give a reasonable estimate of when the motor is about to fry?

Finally, if these questions make it obvious that I shouldn't dive in, somebody please tell me that too. I'm hoping that the tritium line is plug and play enough for me to get going then learn the details and customize things as I go along.

[GerhardRP]

Googling around on the Highlander MGR, I found a picture of one opened. Look near the bottom of this page:
http://www.vibratesoftware.com/html_...nsmissions.htm

[major]

Originally Posted by GerhardRP

Googling around on the Highlander MGR, I found a picture of one opened. Look near the bottom of this page:
http://www.vibratesoftware.com/html_...nsmissions.htm

Cool You think they could have put more copper in there? And do you know if it is liquid cooled?

Thanks,

major

[Ryan800]

So I actually bought one. It's not liquid cooled, but there is a drain plug that leads to the compartment in those pictures, so I suspect there's oil in there which would greatly improve heat transfer to the casing. The is also suggested by the open bearing. I guess I could pull the plug and look, but I don't see any reason just yet.

The main sticking point so far, aside from unknown torque capability and Kv, is that there are no hall effect position sensors, instead a resolver. James at Tritium has been very easy to work with and has suggested that if I can get him the operating frequency and primary:secondary turn ratio for the resolver he would buy one and build this capability into the next revision of their controller. Sounds like work on this would start in a month or two. I'm planning to use an audio frequency generator for my computer and an oscilloscope tomorrow or this weekend to sort out these parameters. Any suggestions for how to do this would be greatly appreciated. I have no experience with electronics, but an EE here at work said this strategy would more or less work.

The backup plan is taking the thing apart, removing the resolver, and shipping it to Australia.

Does anyone know an engineer that works for Toyota?