# Rinehart Motion AC controller



## Technologic (Jul 20, 2008)

davidru said:


> Hi all,
> 
> I've exchanged emails with Larry Rinehart, and it seems he is starting a pilot build of his 100kw AC induction controller. I guess it's all vapor until someone actually gets their hands on one, but it looks very interesting. 6kg, liquid cooled, 450V, 280A continuous, 400A peak, and can drive AC induction or PMAC motors, with or without sensors. I think he is pricing them around $8500.


Overpriced much?


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## etischer (Jun 16, 2008)

I was talking with Larry at Rinehart, he said he is dyno testing with the Ford Siemens motor. $8500 sounds like a deal to me, I don't think anyone knows the work involved. 

I'll hopefully be selling my inverter for the Ford/Siemens motor too, but it won't be much less than the Rinehart one, maybe around 6500. 

There is a huge time investment involved with tuning an inverter to work with a specific motor, and there are only about 300 of the these motors out there. Its tough to make a profit when you can only sell a few pieces. Since there are not many other inverter options out there, that also drives up the price.


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## samborambo (Aug 27, 2008)

David, US$8500 for an AC controller is pretty steep for a 100kW controller. I'm starting a build soon (just bought the donor Toyota MR2 yesterday) using two industrial AC induction motors. 

As I've played with 3 phase VSDs and designed switchmode converters before, I like the challenge of designing and building the inverter controllers. For this build they'll be space/vector controlled based on the Microchip app note with some added logic to share torque appropriately.

I'll share the schematics and board layouts, etc. once I'm done. If you're keen to build the controller from scratch, use standard induction motors and not in a big hurry then this is probably your best bet.

Sam.


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## davidru (Apr 12, 2009)

My thing is mechanical stuff, so I was hoping to buy a proven unit, though I'm not opposed to doing a diy inverter if there is no other cost effective option, and I don't have to etch my own boards ;+}

You bring up motors, and this is an issue. As I understand it, standard industrial induction motors of reasonable size for ev use (say <200lbs) are not capable of useful performance in an on road ev in their stock form at reasonable voltage levels. The HPGC motors are examples of modified induction motors, but as far as I am aware, no larger motors like this exist. We have the option of running several smaller motors in parallel, or perhaps trying to convince these builders to modify a bigger frame motor. From stuff I've gleaned from the evdl, a 4 pole industrial 3 phase motor can be rewired to put phase coils in parallel, increasing it's current capability. Note, This is not the same as switching from delta to wye (or the other way, I can never keep that straight), you actually have to cut wires and splice them together at a common point for each leg. Somewhere there is a picture of the GM EV1 motor taken apart (by Otmar, I believe), and this is visible in the images. The key is that the motor does not have to be completely rewound. I'm thinking something in the 213T frame size or smaller would be about right for a 100kw inverter.

I too have an MR2, really an MRS (or MR2 Spyder here in the states). It's not yet in a state where I would consider it a donor, but I have to say I'm very tempted by the low mass and great handling. Since I'm dreaming (I'm unemployed, the MR2 and a lot of other toys are probably going on the block soon anyway), I'd really like something even lighter, maybe like a Radical SR3, but not for $50k!


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## Technologic (Jul 20, 2008)

etischer said:


> I was talking with Larry at Rinehart, he said he is dyno testing with the Ford Siemens motor. $8500 sounds like a deal to me, I don't think anyone knows the work involved.


The price of a brand new Hyundai Tiburon at the end of the year sale sounds like a deal for a single AC motor controller?

People need to get off the paint sniffing.


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## samborambo (Aug 27, 2008)

The quote I got from ABB for two 4 pole 9.2kW aluminium 132M frame motors with about 4.5 to 5x short term rating is NZ$2000 (around US$1250) each. That's a little expensive and I'm questioning the need of going to an aluminium frame (most of the weight is in the iron core and copper windings). I'll investigate that further. These are 230V/400V 50Hz motors in delta/wye and 59kg each. I still need 3:1 reduction toothed belts from the motors to the half-shafts. My battery pack will be around 690Vx40Ah LiFePo4.

Apparently the MRS has much improved handling over the MR2. It looks too much like a hairdresser's car for my taste! Many people have suggested that since the conversion budget is about NZ$25,000 I should have spent more on the donor car. As it happens I found this 1990 MR2 with a blown motor and deregistered for NZ$380 - otherwise very good condition. Here in NZ if the car has been deregistered it needs to go through a full mechanical certification which is why no one else was interested in it. Certification is required anyway when converting to electric.

I understand where you're coming from though. When I first looked at industrial induction motors I immediately dismissed them as not having the power density required. However, after looking at what else is available, when you crunch the numbers, induction motors aren't THAT much heavier for their power rating. More metal in the motor means a higher specific heat capacity and better short term rating. I've designed for the continuous power rating to be the highway cruising top speed of 130km/h. I highly doubt that the short term bursts of acceleration will cause any heating issues especially in NZ's moderate climate. To be on the safe side, the motor quote included PTC resistors fitted for dynamic rating.

Sam.


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## davidru (Apr 12, 2009)

"Apparently the MRS has much improved handling over the MR2. It looks too much like a hairdresser's car for my taste!"

It's ironic then, as I've lost most of my hair.

So, your bus voltage is up there, that's another solution, wire the motor for 230 and run at 480 VAC (rms). Or will you use the hv winding?

I would love to find a cheaper solution, but just having spent weeks swapping a 1000lb diesel motor in an Isuzu NQR (Isuzu ELF in the rest of the world), my taste for "bargains" is diminished somewhat.

I found marathon in the US lists a bunch of aluminum frame motors in their "Black Max" series. They aren't substantially lighter than their steel frame counterparts, which is puzzling.


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## samborambo (Aug 27, 2008)

davidru said:


> So, your bus voltage is up there, that's another solution, wire the motor for 230 and run at 480 VAC (rms). Or will you use the hv winding?


Yeah, I'll wire it in delta to give the upper voltage headroom. I have 200A IGBT six packs on hand for the controllers which will hit current limit at low speed/voltage. I don't really want to fork out for 400A IGBTs so if I need the extra acceleration down low, I'll put a delta/star contactor on each motor.

Sam.


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## etischer (Jun 16, 2008)

samborambo said:


> I still need 3:1 reduction toothed belts from the motors to the half-shafts.
> 
> 
> To be on the safe side, the motor quote included PTC resistors fitted for dynamic rating.
> ...


Make sure the toothed belt/sprocket you choose is quiet. At high rpms, they can get pretty loud. The belt/sprockets may need to tolerate angular misalignment to allow for suspension travel, not sure what your plan is. 

If you are running your controllers in a torque mode, you will have current feedback. You can simply integrate the current squared over time to know when the motor is over loaded, and current should be reduced. I^2 * T is what is typically used for motor overload protection and is what a PTC resistor would do. Nice thing about programatic overload, is it can limit current instead of shutting the controller off completely. 

It's always nice to see someone doing something that hasn't been done before!

Oh yea, your 200A IGBTs are probably 200A per phase, so 345A for 3 phases.


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## Guest (Jun 1, 2009)

I will stick with DC for now. Don't price yourself out of business before you start. My dreams are dashed on building a nice AC system VW. : (


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## Bluefang (Jun 19, 2009)

Sounds great Samborambo, i for one will be very interested in the design of your controller as i should be getting 2 identical 3-phase motors from work rated at 7.5kw which i ll be either coupling together to drive the vehicle or have one on each axle to make it 4wheel drive.


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