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RX400H transaxle

Posted: Thu, 13 Jan 2011, 16:39
by PlanB
I've been hanging around this forum like a timid wall flower this last eighteen months trying to get up to speed on EV conversions. I've decided if I don't make some sort of financial commitment I'm never gonnna get started. I've found a rear electric transaxle (motor-in-diff)from a Lexus RX400H wrecker stateside. It's 31kg, 50kw, 131Nm, 288v, 3 phase, 9 pole, perm mag for under nine hundred bucks so I think I'll buy it.
The missus is looking doubtful, but the boys (well young men in their twenties now) reckon "go for it". What's the worse that can happen?

RX400H transaxle

Posted: Thu, 13 Jan 2011, 21:17
by Electrocycle
shipping might be a fair bit, but assuming you can install that setup into another car it should work pretty well!

It'd go well with a Tritium controller :)

RX400H transaxle

Posted: Fri, 14 Jan 2011, 01:40
by antiscab
sounds like a plan, though i doubt its 9 pole, 8 or 10 probably (always an even number).

good setup for a small plugin in hybrid, or even just a really small EV.

or a way to add regen to a RWD DC conversion.

Matt

RX400H transaxle

Posted: Fri, 14 Jan 2011, 14:20
by PlanB
What the hell, I can always get it chromed & use it as a novelty door stop if things don't work out.

RX400H transaxle

Posted: Fri, 14 Jan 2011, 17:18
by acmotor
No no, go for it.
Probably the mechanical mount up will be the biggest task unless it is going straight back into an lexus toyota ? The electrical should be fairly straight forward. Most modern VFDs will drive synchronous AC (PM) motors at a voltage of your selection.
The 50kW is substantial. The iMiEV is 47kW in 1200kg EV and that works.
Chase down all the technical info you can on the motor. Is it BLDC or synchronous AC i.e. does it have commutating pickups on the rotor ?
I would think the motor is saleable anyway if you decided down the track not to make an EV of it.

RX400H transaxle

Posted: Fri, 14 Jan 2011, 19:43
by PlanB
tks Tuarn, I'm in awe of what guys like you have done. I was thinking if I could get into something light like a Suzuki Cappucino (650kg)it might have respectable performance. First thing is get it here in one piece then find a controller to run it.

RX400H transaxle

Posted: Sat, 15 Jan 2011, 18:17
by 7circle
I've seen a couple of Diahatsu Coupe cars for sale on the road lately.

Wow a Cappacino with a RX450H motor drive would be crazily fun.

Image

RX400H transaxle

Posted: Mon, 17 Jan 2011, 21:43
by ryan800
Hello PlanB and everyone else, I have one of these motors so I thought I'd comment... I live the the US so the motor is easy to get, but a controller is much more difficult. The tritium controller is still the best option because if it's high voltage and their willingness to work with the DIY crowd. I have one on order that should arrive at the end of Feb, although not sure if the flooding will change that.

Your stats are close, but to make a few corrections, it's 41kg, operates on 650V (288V battery pack with boost converter) and 8 poles. Everything else looks right.

The gear ratio is 6.859:1, and from the information I've found the peak rpm with 650V pack is 10752. You can run the math for your battery pack and tire size yourself, but what I have found is that it should work but there's not a lot of margin on top speed. A battery pack that sags to 384V (128 cells, 3.0vpc) and 185-65-15 tires will have a top speed of 108km/h.

Cooling might be an issue if you push it, but it's partially filled with ATF, so running that through a radiator should help increase the continuous power a bit if needed.

Rotor position is calculated using a resolver, so make sure whatever controller you use works with that - Tritium's controller does. Actually, James ("engineering director" at Tritium) wasn't sure he could make it work without seeing the motor, but after developing a resolver interface for another client, he was confident that he could make it work given the operating frequency and winding ratio. Very impressive customer service actually.


One last thing: the motor has a thermistor embedded, but I don't know any specifics. It reads (about) 74k ohms at 17C and is NTC type. Can anyone out there give me a part number or resistance-temp curve parameters from just that?

Keep us updated with how things turn out, especially if you decide to contact Tritium. I think actually having this motor would make the resolver interface a bit more of a certain prospect. If you have any questions I'll try to answer them, although most of the stuff I've found so far came from the internet.

-Ryan

RX400H transaxle

Posted: Mon, 17 Jan 2011, 21:56
by Johny
ryan800 wrote:One last thing: the motor has a thermistor embedded, but I don't know any specifics. It reads (about) 74k ohms at 17C and is NTC type. Can anyone out there give me a part number or resistance-temp curve parameters from just that?
Hi Ryan. Not enough info. Maybe you could get the motor up to 30 degrees C and measure it there as well???
Or drop it down in temperature. It would have to be for a fair amount of time to get the thermistor up/down reliably?

RX400H transaxle

Posted: Thu, 20 Jan 2011, 02:17
by PlanB
tks for the motor update Ryan. It would be great to track down who actually makes the beast, I bet Toyota contracted it out.
I was about to click the paypal button for mine when I got the urge to google the car parts supplier in the USA & their results on some of the consumer websites stateside were'nt all that good. So I'm back in limbo at the mo.
Really interested in your Tritium/Rx400H package, a logical combo if ever there was one. What mass vehicle are you thinking of as a donor?

RX400H transaxle

Posted: Sat, 22 Jan 2011, 11:08
by ryan800
Bummer, there seem to be plenty of these around though, so if you're willing to pay for the shipping I'm sure someone will send it. When I bought mine I just called a few places until I actually talked to someone on the phone who seemed reasonable. If you pay with credit card I imagine you have pretty good recourse against non-shippers. Also, they come out of wrecked cars so make sure you get pictures of the actual unit, especially the mount points.

I'm putting it in a Saturn sw (wagon), which I'm not sure if they have those in Australia, but it weighs less than 1100kg in most trims. I'm hoping to stuff it pretty full of batteries for a converted weight of about 1315kg.

I left the motor outside last night and measured the thermistor resistance when I woke up. Outside temp was 7.8C, resistance was 108.3k ohms. I think the best inside data point I have for room temp is 16.7C, 73.1k ohms. So I guess that yields a B-parameter of 3559K and Ro=52.3k ohms. So probably a 50k ntc thermistor... anyone know of a part number that would be likely? At some point I'll heat the motor up and get another data point. Obviously these measurements are pretty crude, but probably about 5C is all the accuracy I need. I figure keeping it under 150C is a conservative and hopefully acheivable goal... These guys had the prius motor stator widings up to 200C during their testing:

http://www.osti.gov/bridge/purl.cover.j ... 29-WIfqPO/

-Ryan

RX400H transaxle

Posted: Sat, 22 Jan 2011, 18:28
by PlanB
I'll keep hunting Ryan, if & when I score one that works we can compare notes hopefully.

RX400H transaxle

Posted: Wed, 26 Jan 2011, 20:36
by PlanB
Just thinking out loud here. If the high voltage version of the Tritium controller can take 720v that's 720/4.2 = 171 cells for 718v nominal at full charge. I think RMS on the motor is batt/1.4 = 508v?
From your numbers Ryan it looks like motor RPM=battx16.75? So 508x16.75=8509RPM which,on 15" wheels(60cm dia tyres) with the 6.86:1 reduction, is top speed of 140km/hr.

RX400H transaxle

Posted: Wed, 26 Jan 2011, 20:50
by antiscab
you only charge to 3.6v cell average (or lower), so max cells for 720v max is more like 200 cells.

Matt

RX400H transaxle

Posted: Thu, 27 Jan 2011, 16:13
by PlanB
Does anybody have any data sheets for 18650 format Lithiums? These sample 4AHrs I got off ebay say 3.7v nominal charge to 4.2v?

RX400H transaxle

Posted: Fri, 28 Jan 2011, 11:31
by antiscab
ah, lithium cobalt variety,
4.2v for the cv stage of cc-cv is correct for Lithium Cobalt.

Matt

RX400H transaxle

Posted: Fri, 28 Jan 2011, 19:36
by PlanB
Tks Matt. Ran some internal resistance tests on the 4Ahr 18650s to day. They arrived pretty much fully charged at 3.80v & I fiddled around a bit till I got them to a plateau at 3.65v. At the 4A C1 rate the voltage dropped to 3.00v & returned to 3.60v after the 1min test. So (3.6-3.00)/4 = 0.15R.
Bit disappointed actually, was hoping for a value about half that. Works out to 2.4w/cell (20% of usable power) at C1 or 12kw instantaneous for a 5000cell/250kg pack.
Looks like Tesla are right, 18650s need active cooling.

RX400H transaxle

Posted: Fri, 04 Feb 2011, 02:24
by PlanB
Been trying to work out what I need in a VSD to run the 50kw 8 pole 131Nm Rx400H transaxle. Didn't get very far till ACMotor helped me out & sent some numbers, half a day with pocket calculator & I think I've got it figured out?
1)Starting point is Ryans 10750RPM at 650v. From here I=P/V=50k/650=77A. And T=30P/PiS=(30 x 50k)/(3.142x10750)= 44Nm. Further k=T/I=44/77=0.57Nm/A. Also F=SN/120=10752x8/120=717Hz.
2)Peak torque is 131Nm so S=30P/PiT=(30x50k)/3.142x131=3644RPM. I=T/k=131/0.57=230A & V=P/I=50k/230=217v. F=SN/120=3644x8/120=243Hz
So at one end I need a VSD capable of 230A at 217v 243Hz & at the other extreme 77A at 650v 717Hz.
Suggestions anybody?

RX400H transaxle

Posted: Fri, 04 Feb 2011, 02:48
by antiscab
if you used a ~160kva 460v nominal (will be listed as 380v-500v) VFD you would be able to get 140kw out of that motor (no field weakening).

alternatively, you could get an 80kva 230vac nominal VFD you would be able to get 70kw, from 5000rpm (motor) onwards.

650v I presume is dc V (so 460vac)
230A would again be from the battery (so ~190A line/phase current).

another alternative would be to use a tritium controller.
that gives 280vac, and plenty of amps.
you should be able to get 80 or 90kw.

Matt

RX400H transaxle

Posted: Fri, 04 Feb 2011, 03:30
by PlanB
RMS AC vs DC volts!? Hmmm, Ryan did say 10752RPM from a 650v batt pack didn't he Matt? I should rework those numbers,
1)Starting point is Ryans 10750RPM at 650v(DC)= 650/1.4=460v(AC). From here I=P/V=50k/460=109A. And T=30P/PiS=(30 x 50k)/(3.142x10750)= 44Nm. Further k=T/I=44/109=0.40Nm/A. Also F=SN/120=10752x8/120=717Hz.
2)Peak torque is 131Nm so S=30P/PiT=(30x50k)/3.142x131=3644RPM. I=T/k=131/0.40=328A & V=P/I=50k/328=152v. F=SN/120=3644x8/120=243Hz
So at one end I need a VSD capable of 328A at 152v 243Hz & at the other extreme 109A at 460v 717Hz.

RX400H transaxle

Posted: Sat, 05 Mar 2011, 12:21
by Mesuge
Bravo, I'm glad that after years of drumming up this option of re-using/recycling HSD components, somebody picked up the challange finally. Btw. a little hint, as discussed in older threads, there is not only Toyota (albeit highest production numbers), they licensed (or use same supplier) it to all major OEMs out there..

Also you might look at efficiency maps for given list of controllers at suggested rpm/voltage (for ideal driving envelope), to squeeze most out of it, obviously Tritium should be leading the pack.

Btw. from what I recall at least Toyota ver. describes the RX ver. as <<1500RPM peak torque, but that is probably function/limitation of the overall HSD controller/battery/gearing combo. Again, some of the bigger SUVs might be eventually different, e.g. Higlander hybrid datasheet seems the same: 67 HP @ 4610/5120rpm etc. So, it makes sense with ~6.8x internal gearing.

Not sure how many variations/licenses there are, perhaps RX/Highlander + licensed/copycats GM/Daimler/BMW/Fiat-Chrysler have got exactly the same unit, at least for the moment, although the latest gen of their hybrid alliance has got awd solved via shaft/differential.

2010 Highlander
Drives rear wheels, regeneration during braking
Permanent magnet motor AC 650V
max output: 68 hp (50 kw) @ 4,610 – 5,120 rpm
max torque: 96 lb.-ft. @ 0-610 rpm

--
On related topic, some of the SUVs in the "active hybrid" aliance feature quite powerfull mg1/mg2 HV perms: Escalade, GMC Yukon, Chevy Tahoe, ML 450, BMW x6 and other hybrids
--
On tangential topic. After all those years there seems to be only one somewhat documented project on recycling gen2 Prius powerstage with new control board, at the moment it's working in crude fashion open loop, but there are problems with low torque and overall operations. Perhaps close loop and better performace/reliability in the future:
http://www.diyelectriccar.com/forums/sh ... stcount=48

RX400H transaxle

Posted: Wed, 04 May 2011, 20:52
by PlanB
What do we know about creative dynomometering people? The Lexus transaxle has 2 half shaft outputs so coupling just one of them to a conventional dyno doesn't work even if you lock the other one (because that alters the internal gearing ratio).

RX400H transaxle

Posted: Wed, 04 May 2011, 23:17
by Electrocycle
if you put some wheels on it you can run it on any normal chassis dyno, or you could use a hub dyno.

RX400H transaxle

Posted: Mon, 09 May 2011, 21:08
by PlanB
Turns out this is an IPM motor. According to google the rotor saliency of IPMs has made them the darlings of the HVAC industry with 5%-15% better efficiencies.
Alas TJ reckons this motor is only good for 30kw tops with the standard wavesculptor. I'm running out of ideas here. Anybody know of VSD that can handle 700v+ DC & deliver as per below?
1)Starting point is Ryans 10750RPM at 650v(DC)= 650/1.4=460v(AC). From here I=P/V=50k/460=109A. And T=30P/PiS=(30 x 50k)/(3.142x10750)= 44Nm. Further k=T/I=44/109=0.40Nm/A. Also F=SN/120=10752x8/120=717Hz.
2)Peak torque is 131Nm so S=30P/PiT=(30x50k)/3.142x131=3644RPM. I=T/k=131/0.40=328A & V=P/I=50k/328=152v. F=SN/120=3644x8/120=243Hz
So at one end I need a VSD capable of 328A at 152v 243Hz & at the other extreme 109A at 460v 717Hz.


RX400H transaxle

Posted: Mon, 13 Jun 2011, 00:09
by Ilya
Hi from Russia! I was looking for information about RX400H transahle, and found your forum! I managed to gather much information about RX400H transahle, more convenient unit for electric I've never met! I recently bought RX400H transahle, for $ 500) I want to install it in my Honda Insight 2000 and abandon the gasoline!
If you need information about RX400H transahle - ready to respond!