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Old 08-31-2014, 12:17 AM   #7 (permalink)
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Yes, I'm familiar with the voltage they require.

If one uses NiMh cells; yes - it will require a LOT, because the voltage is less than half that of the Lithium cells I am using.

The controller is going to be orders of magnitude better than "a carbon pile" and it's being developed right here. To make full use of this motor's capability requires knowledge of it's advanced magnetic structure. If one takes advantage of the amazing design Toyota did, then it's possible to make use of the reluctance torque to help fight the back-emf that starts to dominate at high rpm.

If I remember correctly, there was also a thread on DIYEV about using this motor. The conversion was a Saturn, and I think (I could be wrong here) he used a Prius sub-300V battery pack and a standard BLDC motor controller. To be perfectly honest, the author of that thread wasn't happy with the results. I definitely DO NOT want to diss on the author of that thread. He was doing ground-breaking work and was very innovative. If I could point out two reasons for his dissappointment 1) the vehicle was a bit heavy for a 50kW power source. 2) I doubt he got anywhere near 50kW, simply because the power source was supplying only half of what the motor was designed for.

While it **may** be possible to rewind this motor for lower voltages, I am not going that route. There are a number of extremely well-executed tests on these motors indicating the necessity of the high voltage. In addition, there is some excellent information from Toyota about this as well.

Here is a paper written by Munehiro Kamiya: "Development of Traction Drive Motors for the Toyota Hybrid System"
The paper details the power and efficiency advantages for increasing the voltage to 650V.

In addition, there are a mind-bending number of tests done by Oak Ridge National Labs on the various Toyota Hybrid systems. This is a perfect example of our government labs going all out with amazing results. For example:

SciTech Connect: Report on Toyota/Prius Motor Torque Capability, Torque Property, No-Load Back EMF, and Mechanical Losses, Revised May 2007


Reading a few of these publications leads one to the conclusion that Toyota might have a pretty good idea of what they are doing. While dropping the voltage significantly may reduce the amount of cells required, there are some very complelling reasons to use those scary-high voltages.

While I call this thread "hot-rodding" the MGR, I do NOT consider dropping the supply voltage significantly a method for improving the performance. It would be a bit like dropping the boost pressure on a turbocharged car and calling that a performance improvement.

Ok, to answer some questions about what I'M going to be doing with this.
1) They (yes, more than 1) are going to be the primary power source for an EV.
2) I am using a high voltage lithium pack to supply the power. The modules are from a Nissan Leaf, and so far I have a pack with over 400V. Boosting the pack to the full 600+V will require another 24 modules, which is not ridiculously expensive or heavy.

- E*clipse

Last edited by e*clipse; 08-31-2014 at 12:20 AM.. Reason: add link for controller
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