# BAE HybriDrive drive unit, large induction motor with planetary gearbox... Opinions?



## 1000EE-Monarch (May 15, 2018)

I just got this rather unusual electric drive unit made by BAE HybriDrive.

It was sold at auction by a BAE division here locally in San Jose that engages in R&D, maintenance, upgrades, etc. on military tracked aromored vehicles. It was sold by them circa 2015 and looked fairly modern the first time I saw it.

It has an induction motor in the rear half, oil cooled, and a resolver for feedback. The front half has what must be a planetary gear reduction. Reduction ratio is 4.75:1. It weights about 300Lbs

The following is speculation on my part. It was probably one of two Electric Drive Units in a tracked vehicle weighting around 50K lbs, each DU driving one track. I'm guessing that it was driveshaft coupled to the final drive gear box for one more stage of reduction before driving the track.

My current guess on specs:
200-400 kw
400-600 V
4-pole motor, so 400hz ish
12-14 k RPM rotor speed
2-2.5 RPM output speed

I have contacted BAE HybriDrive by email and phone with no luck (not surprised). Looking at their web site did to yield any clues, none of their offerings look like this unit. I'm guessing it was an internal R&D prototype. Hand written is on it is "Rev. D, SN 0055", supporting that guess.

I'm toying with the idea of building something with it. An electric Jeep Wrangler is tempting but this seems a touch big for that. Putting it in a 3/4 ton pickup is another idea.

Anyone recognize this beast? Any ideas? I might have to open it up and analyze further. 










































Thanks!
Alex.


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## brian_ (Feb 7, 2017)

Sorry, I don't have any specific information about this unit, just a comment...


1000EE-Monarch said:


> The following is speculation on my part. It was probably one of two Electric Drive Units in a tracked vehicle weighting around 50K lbs, each DU driving one track. I'm guessing that it was driveshaft coupled to the final drive gear box for one more stage of reduction before driving the track.


That's plausible, but with that drive yoke output, I would guess that it was intended to swap in place of the transmission of a conventional medium-duty truck or bus, for a conversion to series hybrid or for a straight battery-electric. Most of BAE's HybriDrive bus systems are series configurations, designed to mount in conventional chassis configurations.

With a reduction gearbox and yoke output, the MTS (modular traction system) (without the integrated starter generator) looks like the same configuration; however, that MTS is for heavy buses and trucks (20 or 30 tons GVW), while this found unit might be for a medium-duty (10 to 15 tons?). I assume that the speeds in the specs in that MTS sheet are for the final output, not the motor shaft.

Check out slide 7 of this Alexander Dennis Presentation on Hybrid Buses: the unit at the top of the "Legacy system" box looks _very_ familiar...


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## 1000EE-Monarch (May 15, 2018)

brian_ said:


> Check out slide 7 of this Alexander Dennis Presentation on Hybrid Buses: the unit at the top of the "Legacy system" box looks _very_ familiar...












Good work there! Looks like a match! The 190 Kw is a touch disappointing but within the realm of reality and would certainly be fun for a Jeep or something like that.

I also agree with you that it looks like something to fir the form factor of a transmission in an ICE bus or truck.

Now, what to drive it with... A large industrial vector drive VFD would work, anyone have ideas on a better option?

Thanks,
Alex


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## brian_ (Feb 7, 2017)

1000EE-Monarch said:


> The 190 Kw is a touch disappointing but within the realm of reality and would certainly be fun for a Jeep or something like that.


I'm guessing (and it's _only_ a guess) that the 190 kW is a continuous power rating. The MTS specs show an "intermittent" power 12.5% higher than continuous, and a "peak" power 25% higher than continuous; perhaps this unit is similar.


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## piotrsko (Dec 9, 2007)

For a rock crawler it would be interesting. Commercial style unit so it has bunches of torque


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## 1000EE-Monarch (May 15, 2018)

brian_ said:


> I'm guessing (and it's _only_ a guess) that the 190 kW is a continuous power rating. The MTS specs show an "intermittent" power 12.5% higher than continuous, and a "peak" power 25% higher than continuous; perhaps this unit is similar.


I agree. The electrical terminals are huge and it looks to have enough thermal mass. Compared to a Tesla DU, this thing is massive! 

BTW all my buddies that have seen it, are making fun of me for even considering using this vs. a Tesla DU. This thing isn't what you would call power-dense in comparison, but is rugged looking, and, well, it's here. A bird in the hand vs the sky.

I don't have much to complain about, the 250-300 HP would be more than enough to break axles and spin tires on a Jeep Wrangler Unlimited. Won't be too impressive on a 7000Lbs 3/4 ton pickup. And those are the two silly ideas I currently have in mind....

If BAE does not come though with data, I'll still do exploratory surgery just to figure out the wire cross section and turns ratio in an attempt to figure out rated voltage. The other weird one will be base speed and maximum rotor RPM. I'm thinking max freq. will be around 400Hz and base maybe 60 ish? Or maybe I've been around too much industrial and aircraft motors and have those two numbers stuck in my head lol.


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## boekel (Nov 10, 2010)

That thing is much to big and heavy for you...

I'll help you and buy it to use in a boat


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## 1000EE-Monarch (May 15, 2018)

boekel said:


> That thing is much to big and heavy for you...
> 
> I'll help you and buy it to use in a boat


I agree, this maybe less than idea for what I'm thinking of doing with it... And maybe perfect for a boat. May I ask what you have in mind? Sailboat, and charge the batteries when winds are good?

I'll play with this for a while till I either build something with this or give up and go a different route.... Too early to tell, I've only had it for a week.

I think I'll have to pop it open and make a youtube video out of it...


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## aeroscott (Jan 5, 2008)

I've been looking for a hybrid trans for my 5.9 b series Cummings . I have a 47 ft. steel sailboat that needs a engine . I am looking for another 47ft boat to turn them into a catermran work boat. built a 52ft. catermarn and lost it to a arson fire.
Looks like there will be no shortage of these drive systems.


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## boekel (Nov 10, 2010)

1000EE-Monarch said:


> I agree, this maybe less than idea for what I'm thinking of doing with it... And maybe perfect for a boat. May I ask what you have in mind? Sailboat, and charge the batteries when winds are good?
> 
> I'll play with this for a while till I either build something with this or give up and go a different route.... Too early to tell, I've only had it for a week.
> 
> I think I'll have to pop it open and make a youtube video out of it...


It depends on the reduction rate - if the output rpm is low enough for a large propellor, it would be a nice choice for a working barge or tugboat.


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## 1000EE-Monarch (May 15, 2018)

aeroscott said:


> I've been looking for a hybrid trans for my 5.9 b series Cummings .


I happen to like those things! Have a couple of 2001 5.9l Cummins Dodges.... I can see doing a diesel electric hybrid with this drive unit in, say, a 6.0 Ford with a blown up engine and a 4BT cummins with ~ 80kw alternator.

The reduction is 4.75:1, so would probably need more reduction for a boat... But is about the same as a small(er) diesel.


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## electro wrks (Mar 5, 2012)

1000EE-Monarch said:


> I just got this rather unusual electric drive unit made by BAE HybriDrive.
> 
> It was sold at auction by a BAE division here locally in San Jose that engages in R&D, maintenance, upgrades, etc. on military tracked aromored vehicles. It was sold by them circa 2015 and looked fairly modern the first time I saw it.
> 
> ...


Great find. Just to clarify: is the output RPM 2-2.5k RPM or 2-2.5 RPM as written? Also, do you have a shot of the non-output end of the unit?


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## Karter2 (Nov 17, 2011)

E-works..
No big thing but,....is it really necessary to re-quote the entire post, including all photos,..just to ask a simple question .??
.....especially when that question was answered in the preceeding post !


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## 1000EE-Monarch (May 15, 2018)

electro wrks said:


> Great find. Just to clarify: is the output RPM 2-2.5k RPM or 2-2.5 RPM as written? Also, do you have a shot of the non-output end of the unit?


I meant 2-2.5K RPM, but, let me re-do the math (altho i'm still guessing a bit here).

400Hz max frequency, 4-pole would be ~ 12K RPM rotor speed.
4.75 reduction would be ~2,500RPM out. Very similar to a diesel engine.

Here's a shot of the back:










The connector in the center is for the resolver. The resolver has a traditional military/aerospace look to it inside, very 60's tech. The other connector must be for temp. sensor, etc.

I'm itching to take off the back cover, look inside, and make a video out of it.... One of these evenings! It looks pretty easy to open up, but will be messy (oily) and i will have to be careful of the resolver, bearings, etc. Planning on doing it pointing output down in a fixture on on the forks of a forklift. With a drip pan underneath lol.

Another reason for taking it apart is to understand the cooling / lube "plumbing" inside..... Which is the inlet, does it matter, bearing lubrication, etc.


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