# Azure Dynamics/Solectria AT1200 Gearbox, Shown With Azure Dynamics/Solectria AC24 Mo



## stevesnj (Apr 13, 2009)

Anyone use this combination and pro's and con's... want to use this combination and need to find out how it's been working.

http://www.electroauto.com/catalog/acgearbox.shtml


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## tomofreno (Mar 3, 2009)

If I recall correctly the gear ratio on this box is about 10:1. That is in between first and second gear on most small cars, so will work ok if you are happy with top speed around 50 mph or so for use on secondary roads. Not ok if you want a vehicle to use on the highway. You will need a lower gear ratio to get to highway speeds and have decent acceleration above 40 mph I think.


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## TheSGC (Nov 15, 2007)

At my college we have a fleet of the Solectria Geo Metros which uses these, and they have a top speed of about 65 MPH but have a terrible time with these MA hills (thought it was just me...) and it turns out that a FB1-4001 with 120 volt system has way more power than the AC24 motors. 

Take a good look at the data sheets, they have a peak torque of 55 ft-lbs (half of a 4cyl ICE engine, and a 2/3 of a low end DC system)

If you want AC, the AC55 is the only real decent thing.

Oh, and the AT1200 is actually a modified Honda Civic transmission with a few tweaks.


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## stevesnj (Apr 13, 2009)

I really need a vehicle that can do 60-65 mph so I guess this would be out. Is there anyone else that sells single speed gearboxes? I like the fact I can use a push button gear selector as the AT1200 can via the controller. I would love to use this in the front of my Miata and hook t to the driveshaft to the differential. The diff is 3.90 gears. Any gear ratio website for this combination? Like plug in the numbers and get a final speed?


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## Drew (Jul 26, 2009)

stevesnj said:


> I really need a vehicle that can do 60-65 mph so I guess this would be out. Is there anyone else that sells single speed gearboxes? I like the fact I can use a push button gear selector as the AT1200 can via the controller. I would love to use this in the front of my Miata and hook t to the driveshaft to the differential. The diff is 3.90 gears. Any gear ratio website for this combination? Like plug in the numbers and get a final speed?



That IS a differential, plus a fixed rate gearbox. You'll get 10:1

this means that the maximum output speed is 1100RPM and you'll need half shafts to suit if yours don't have the correct spline on them.

The only thing you have to do is get the rolling radius of your tyres and times it by 2 x Pi to get your distance per revolution, times that by your 1100RPM, times by 60 to get hours and convert to convenient units.


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## tomofreno (Mar 3, 2009)

There is an "ev calculator" at http://www.evconvert.com/tools/evcalc which might help. There is a spreadsheet, referred to as "ev calculator" at electricnevada.org where you input the variables for your vehicle such as mass, gear ratios, drag coeff etc, and it will calculates things like available torque, power, and acceleration at various vehicle speeds. There are also charts of available and required torque, the intersection of which tells you the max speed of the vehicle. The input gear ratios are the overall ratio, transmission and differential. If you scroll down the spreadsheet you will see these output parameters are given for different motor/controller combinations. The one for the Azure D. AC24LS only gives results if the battery pack voltage is at least 144VDC (minimum per Azure spec). You could start by just using the input data that is there for a Suzuki Swift, and increasing the number of "batteries" (LiFePO4 cells) to 45 to get 144V pack voltage. The Azure D. site says the 1200 gives 10:1 or 12:1 overall gear ratio including differential. Scroll down to the bottom of the input variable column and you will see this is between first and second gear for the Swift. Use the right-left scroll bar at the bottom to scroll left and find the tab marked "AC24LS,DMOC445". Click on it to see a chart of available and required torque. In first gear max speed is about 55 mph, and in second it is about 75 mph. An overall gear ratio of 12:1 is close to first gear, so top speed might be around 60 mph, whereas 10:1 is about mid-way between first and second, so top speed might be around 65 mph. That is only part of the story though, if you go back to the spreadsheet by clicking the tab "data", and scroll down to the section for the AC24LS, you can see rows for "available power" and "available acceleration". You can see the max output power will be down at 20 to 30 mph for first gear, and much better at 30 to about 55 mph for second gear. So you will have poor acceleration above 40 mph or so if the overall ratio is 12:1. You can get to 60 mph but it will take a while. You can estimate how long by using the available acceleration. The acceration from 0 to 10 mph is about 7.5 mph/sec in first gear so it will take about 10/7.5 = 1.3 seconds to accelerate to 10 mph. Between 10 and 20 mph average acceleration will be about (7.5+6)/2 = 6.7 mph/sec, so it will take about 10/6.7 = 1.5 seconds, plus 1.3 seconds, or 2.8 seconds to accelerate from 0 to 20 mph. Repeat this for other speeds to get an estimate of the time to accelerate to a given speed. The spreadsheet is a bit difficult to get used to, but it gives you a lot of information.

Tom


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## toyolla2 (Jun 21, 2010)

AEVA site, see "ABB Motor and VFD selection"
it's from Technical Discussion, Electronics motors and controllers.

About the Azure product, Richo says the AC24LS is based on an inferior 5.5Kw 4-pole ACIM that has been rewound for 40Vac/70Vac delta/star. 

Better to purchase locally an Aluminum motor for $600 new and get it rewound for $800. Myself I would suggest a star winding for 25Vac. Meaning that the new terminal voltage at 1500rpm @ 50Hz. will be 25Vac. Your all important V/Hz figure will now be 25/50 or 0.5. 

Winding at this low a value allows the use of 300 Amp controllers on 144vDC supplies and keeps you away from the more daunting 312Vdc battery pack. 

The V/Hz on the original GM EV1 was 0.74 V/Hz using a 10.5 : 1 gear ratio and a 312Vdc pack. Most industrial motors e.g. 50/60Hz 480volt are around 8.0V/Hz which explains why they are unsuitable for EV work as is. So select either a new or an EBAY special to be rewound for the job. It does cost $$$ and not all rewinders will do unusual voltages.

This is yet another case where mathematics and algebra are unneeded. You want the same total amps flowing down each stator slot just fewer wires carrying it. How few ? Well find the fraction of the new required voltage divided by the original nameplate voltage and multiply the fraction by the number of wires pulled out of that slot. 

If this route is chosen then while the motor is stripped remember to have them send off the rotor to be balanced for 9000rpm at the same time, or at least as high as they can. Even a 6000rpm balance will be usable in this application at 11000rpm. 

Of course you could request a new machine to be bult on your spec. Since the voltage specification only involves changing the wire diameter -everything else besides the name plate remains unchanged - the upcharge is not as large as you'd think. Unlike that for a DC armature rewind for instance.

In today's market, even motors as large as 4kw motors are no longer available off-the-shelf so be prepared to wait 6 months however. 

Re Azure, last March '09 I was priced Can$3500 for an AC24LS which apparently has a Tmax/Tnominal of 2.3. Some say that is as low as it gets. Hmm.. but this is said to be a 15 y.o. design.

The AT1200 gearbox for vertical mount on FWD with 12 :1 was quoted at CAN$ 2633. You should probably try to haggle these prices down about 50%. The AT1200 contains the diff as well and they will build halfshafts to your spec for ~$250 each.

For the expected efficiency improvement i.e. in increased range, that the transverse drive offers over the 90 deg hypoid rear end, the AT1200 is probably one component that is good value for overall system cost. But that's just my opinion. 

The 12:1 ratio will probably require 10500rpm for 60 mph. restricting the top end to about 70mph.
The way to think of it is like you're swapping some fast for some quick ! Single gear ratios always require this tradeoff. 

Sure a two ratio gearbox can help big time but note you are moving the problem elsewhere. Notice that Tesla following their gear box debacle, even with people on staff who were supposed to know what they were doing, eventually came back to single ratio gearing. 

If you consider using this 25Vac rewind together with a 144Vdc pack which will deliver 100Vac maximum - then conventional base speed for this motor will be raised from 1500 rpm to 6000rpm. From then on conventional constant power will extend through 11000rpm while rolling off slightly.

However this motor is anything but conventional. The increase in base speed to 6000 rpm at constant torque from 1500rpm brings the effective motor power up 4 times from 5.5Kw to 22kw. 

The rule for motor power is [new base speed/orig base speed]^0.7 = 6000/1500 ^0.7 = 2.6. So the new continuous power is about 15kw. Copper loss remains the same but iron loss is higher. Had the iron loss remained constant also the motor would be a lot more efficient - same losses but for four times the power output will always do that -and 22kw continuous would be available. Sure there are more iron losses but the efficiency is hardly affected and there is a heck of a lot more useful power as well. So who cares ? Fans can remove the heat at this level.

We are not finished yet. Most gas cars are sized for ten times peak what they require to cruise; while some sports cars 20 times even. 
With the electric vehicle I have just shown how the right gearbox can get four times nominal for a short time and 2.6 times continuous. But we can do even better than that.

Although the motor draws four times the current to get four times the power we have not technically put overcurrent into the winding since the fewer turns of much thicker copper wire will dissipate the exact same amount of heat as the original winding. So we haven't yet put the winding into an overcurrent abuse situation. Now we will.

Technically you can overcurrent most ACIMs up to 4 times along with even more severe timing restraints of course. A practice which allows the short term expectation of incredible amounts of power if the rest of the system is up for it.

So at 1500rpm let's say the new motor nominally draws 200A @ 25Vac but the electronic drive can supply 300A then the effective power can be 5.5Kw times 1.5 (8.5Kw) rising to 34Kw @ 6000 rpm but this is at least 60 second limited. The inverse time law may permit 68Kw for a 30 sec rating even. 

The best motors will take nearly 4 times the current over their continuous ratings while most will do at least 3 times before breakdown torque is reached. That would be 600Amps in our case but concerns for the abuse of the battery pack would kick in long before that.  

There are also a whole bunch of ACIMS with copper rotors now being introduced the SEW servos from France come to mind. 

Sorry, this is yet another ten minute post that started out that way about two hours ago !!

Hope it helps someone but I've been working along these lines lately.


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## powerproducts (Jul 21, 2010)

That is awsome gear. I think you can go for around 40 to 50 mph with it.


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## yarross (Jan 7, 2009)

powerproducts said:


> That is awsome gear. I think you can go for around 40 to 50 mph with it.


It's also way too costly. I think one could do a better deal by fixing existing transmission to one of its gears. Or even better leave transmission intact and save 1st gear for a case like undergound garage driveway.
The only way a fixed gearbox would work is when it's been coupled with sufficiently powerfull motor with good (I mean true constant torque - constant power) characteristics.


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## toyolla2 (Jun 21, 2010)

_- jaross The only way a fixed gearbox would work is when it's been coupled with sufficiently powerfull motor with good (I mean true constant torque - constant power) characteristics._

Too bad you don't supply the figures behind that assertion so an idea of what"sufficiently powerful" actually means.

I challenge anyone to reply to this mechanical problem :

Question. 

An AT1200 12:1 gearbox connects an induction motor that produces a nominal power of 5.5Kw @ 1500 rpm to a wheel of 60" circumference. 

If the motor torque is not to exceed 3 times its nominal torque value then what is the greatest mass in lbs that this automotive powertrain can pull up a 1 in 10 slope ? 

You can neglect frictional losses in the calculation. Please show the working behind your answer. Only ball park accuracy is required since this is supposed to be fun. I'll be back in a couple of weeks with my answer.


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## MJ Monterey (Aug 20, 2009)

Toyolla2, I see the point you are trying to make but the tone of your post is an open invitation to a flame war. We are all trying to learn here. A combative approach and tone is not necessary. E-thugging is not the answer.

A quick scan of tirerack.com leads me to believe that tires less than 20 inches rolling diameter would not be a practical choice on modern street driven cars. Most modern cars have 13inch or larger rim diameters. You would need to check clearances around brakes and suspension before you down sized to 12" rims or less. Also getting DOT approved tires may be an issue in the U.S.. You would also need to confirm if the remaining ground clearance would be sufficient for your driving conditions. Also the smaller diameter tire would require a recalibration of the speedometer.

As a legitimate question:Where does the 1 in 10 slope come from? Is this the max grade on a parking structure per a UBC? I have not yet done research to find out the answer. What is the real world number that should be used?

Would you care to restate your question using researched real world numbers? Also please site the sources or derivations for your asserted numbers.

To the others reading this post. My apologies for the Lecture. I believe Toyolla2 is attempting to make a valid point. I just have a major concern with the tone of this post. I believe he should have guided us through the mathematical process involved so that we can all understand and apply it in the future.

The process would look something like this:
We can derive the instantaneous torque from the power at rpm given.
Torque = 9549 * 5.5kw/ 1500rpm = 35 newton meters

Convert units: 35 NM * 8.85 Inlb/NM = 309.75Inlb
rounding up use 310 Inlb at the motor. 

If we assume no parasitic loss in the drive unit:

Torque at the axle = 12 * 310 inLB= 3720 inLB (this 12 is the gear reductions torque multiplying affect)

I'm going to use 12 inches which is a middle of the road tire radius

Tractive force = 3720 inLB/12in = 310 pounds

At rated power you should be able to maintain a 3100 pound car ascending a 1 in 10 slope. 9300 pounds at three times torque.

Would I drive this car around town, perhaps. With a top speed of under 70 my effective service area would be under 5 miles. To go more than a few miles away I would need to use the freeway. All freeways around here feature rolling hills and 55 or 65 mph speed limit. Most people roll at around 70. These conditions would render the car useless to me because of the single speed gearbox.




toyolla2 said:


> Too bad you don't supply the figures behind that assertion so an idea of what"sufficiently powerful" actually means.
> 
> I challenge anyone to reply to this mechanical problem :
> 
> ...


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## yarross (Jan 7, 2009)

toyolla2 said:


> Too bad you don't supply the figures behind that assertion so an idea of what"sufficiently powerful" actually means.


I mean when your ACIM is not powerfull enough, with fixed gear you can obtain good starting effort or fully utilize motor power at cruising speed, but not both. It's because constant power region is somewhat limited to about 1.5x-2x base speed (caused by pullout torque limit) and beyond that power decays. There's also mechanical speed limit (typically 12000rpm). Large enough motor will cover cruising speed near maximum power point.


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## toyolla2 (Jun 21, 2010)

_At rated power you should be able to maintain a 3100 pound car ascending a 1 in 10 slope. 9300 pounds at three times torque._

Thanks MJ for taking the time to work through the problem.

Unfortunately the silence from others is deafening. No one else seems to understand the importance of the result at least to post a comment that makes sense. 

Our 5.5Kw motor appears to be quite able to pull a mid-size vehicle up a fairly steep incline. And there seems to be plenty of torque in reserve for acceleration once we start utilising the motor's short term 300% rating. I don't doubt that this result flies in the face of most who would have advised the use of 15Kw ~ 22Kw machines when talk of a single gear ratio is proposed. Clearly the above calculation shows they are misguided.

I am prepared, however, to offer the Lance Armstrong award for back pedalling to any that would argue that those larger and more expensive machines will run cooler. Case temperature is not a reliable indicator of comparitive efficiency. The heat generated internally may be the same but it stands to reason the smaller machine of equal efficiency will always run warmer as there is less surface area for dissipating that heat.

MJ, I think we're done here.


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## MJ Monterey (Aug 20, 2009)

Actually, I do not think we are done.

You see yes I have gone through the math for you and have proven that it will hold speed on a MINOR grade. Most everyone agrees you can gear for low speed hill climbing.

At the same overall drive ratio, which includes tire diameter, the mechanical limitations of the motor itself is not viable for extended use at freeway speeds. Which was also one of the original condemnations of the single speed system.

Tire radius of 12" yields an approx 75" circumference tires.

At 70 MPH converting units you are running (70*1760*36/60) 73,920 inches per minute. at steady speed of 70 you need to turn the tires at 985 rpm. which going back through the 12:1 gear reduction puts the motor at about 11,800 RPM. At which point you are near the mechanical limits of the motor. That figure is also approaching the point where I question the motor's ability to produce the torque to overcome aerodynamic drag.

The 11,800 rpm exceeds the max input rpm of 11,000 rpm for the gearbox listed here http://www.electroauto.com/catalog/adgearbox.shtml

The 11,800 rpm requirement also is too close to the 12,000 rpm limit of the motor listed here. http://www.electroauto.com/catalog/admotors.shtml 

I would not be comfortable operating the motor or gearbox in excess of 10,000 rpm motor speed for extended periods of time..

Although possible to run the car as single speed I still contend it is not a viable option with currently available products.

Am I missing something?


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## roflwaffle (Sep 9, 2008)

toyolla2 said:


> Our 5.5Kw motor appears to be quite able to pull a mid-size vehicle up a fairly steep incline. And there seems to be plenty of torque in reserve for acceleration once we start utilising the motor's short term 300% rating. I don't doubt that this result flies in the face of most who would have advised the use of 15Kw ~ 22Kw machines when talk of a single gear ratio is proposed. Clearly the above calculation shows they are misguided.


It depends on the situation and what speeds people find acceptable. Assuming a ~3% grade, then w/ 5.5kW a mid-size vehicle's maximum continuous speed would be ~15mph. If someone lives in a city w/ fairly low speed limits and nice rolling hills it may be OK, but if they live someplace where they wnat higher sustained speeds on 2-3+% grades it couldn't cut it.


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## toyolla2 (Jun 21, 2010)

MJ, I have to apologise for not acknowledging the faux pas I made in incorrectly specifying a 60" circumference tire. I had meant to describe something akin to the Prius tire which has a circumference closer to 70" but your substitution of 75" inches is fine. 
Seems you're not happy with motors at 12,000rpm. I will post shortly on that re the Electrovair II and the EV1.

ROFL take a look at my post #7. I specified the motor to pull 200 Amps at 25Vac @ 1500 rpm and driver permitting the applied voltage can rise to 100Vac @ 6000rpm still at 200 Amps. This will leave the vehicle continuing to climb a 10% incline at around 35 mph - not ~15mph - at which point it will enter the constant power region and could stall out. However the driver need not let that happen since the motor controller is specified to have a 300% reserve in overcurrent available. Although the best motors will accept a 390 % overcurrent before reaching their breakdown torque it is better to stay below that figure.

Clearly this powertrain could go much faster than 35mph on that slope. A 10% slope is fairly steep BTW. I was reading of one individual who climbed 700 meters in 17km which averaged 4.1%; apparently he was able to regen all the way back down but he thought this was an extreme situation. 

There are always going to be situations that test an EV. The question is how likely is it that the driver will meet with the 5 percentile of road condtions that will compromise the 70mph speed limit if they are sufficiently arduous.


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## roflwaffle (Sep 9, 2008)

Given your assumptions (rewound motor) the top speed on a 3% grade would probably be limited to ~60mph for 60s on a 3% grade, but after that it would fall back to whatever the continuous power rating was. If it's 5.5kW then it drops down to ~15mph, and as per the AD spec sheet for the AC24 at ~12kW that's ~30+mph. Like I mentioned before that may be O.K. for some but not for others. Personally it wouldn't cut it because of the 3+ mile 3-4+% grades I have around here, and for $600 more than what you're proposing I could get a Kostov 11"er rated at 40kW continuous/120kW peak. I could see it being O.K. for some people, but others may need more continuous power given their driving conditions.


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## MJ Monterey (Aug 20, 2009)

Perhaps our perspectives of driving conditions are keeping us apart on this subject. Here is my perspective living in coastal central California: 

our freeway overpasses have steeper than 3% grades. Our local ordinances do not question grade unless you go above 10%, and then it's o.k. as long as you take care of water run-off. We have many roads that where put in before building codes were established and I have a few friends that live on what were logging roads that have grades welll in excess of 10%. To get out of the area you typically must climb an approx 2000 ft hill.

Case Highway 17:subtracting the elevation of Scotts Valley from the elevation of "the summit" 1800ft - 561 = 1239 ft and from the wiki on highway 17 we go up this elevation in about 7 miles (12320 ft) This is a freeway with a posted speed limit of 50 and an average grade of 10%. this is the Santa Cruz county side. Santa Clara County side the base is Los Gatos Elevation 344 so 1456 change in altitude in 6 miles (10560 ft) nearly a 14% grade.

A secondary note is that there are a few grades on I80 in the Sierras with flashing lights indicating 5% and 6% grades.


These are some of my realities that I must deal with and plan around.


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## tomofreno (Mar 3, 2009)

> Case Highway 17:subtracting the elevation of Scotts Valley from the elevation of "the summit" 1800ft - 561 = 1239 ft and from the wiki on highway 17 we go up this elevation in about 7 miles (12320 ft) This is a freeway with a posted speed limit of 50 and an average grade of 10%.


 There are 5280 ft/mile, so 7 miles is 36,960 ft, and the grade is 100*1239/36960 = 3.3%. There are 12320 yards in 7 miles.


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## MJ Monterey (Aug 20, 2009)

tomofreno,

Thanks for catching the unit conversion error.

Even with the corrected numbers it illustrates the point.

Unfortunately this is still not a steep road around here. Just long and taxing on sub-prime vehicles.


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## MJ Monterey (Aug 20, 2009)

Drove over this on the way to a friends cabin today. Laureless grade road connects highway 68 to Carmel Valley Road. Speed limit 50. Curves marked as 35 mph Advisories.....

The cabin was at the end of Robinson Canyon Road.
http://www.actc.org/billygoats/bg1map.html 

And the Prius was down to under 25mpg and not happy pulling the grades.


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## toyolla2 (Jun 21, 2010)

Hey MJ you don't give up easily. Your first example was actually an 3.3% grade when your own figures proved that even a 10% grade can be managed by a 5.5Kw motor operating at nominal torque with a 3100lb load. 

You described it as sub prime when there is still a 300% capability to be tapped. It's a fact that most EV motors are expected to run with short term bursts of high power for acceleration and the occasional hill.

By suggesting that a rewound 5.5Kw motor into a 12:1 ratio is subpar you are discounting a solution that could save EV'ers quite a few dollars over a 7.5Kw or 15Kw motor that they would otherwise have purchased. 

This may be my last post as I don't seem to be gaining any traction for the rewinding of motors for high rpm in conjunction with large ratio reducers.


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## roflwaffle (Sep 9, 2008)

It doesn't seem cost effective to shell out $1400 for a 35kW (60s) motor when they could spend $2000 on a motor that can do 40kW continuous and ~120kW for a limited time period.


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## MJ Monterey (Aug 20, 2009)

toyolla2 said:


> Hey MJ you don't give up easily.


No I do not give up easily.


toyolla2 said:


> This may be my last post as I don't seem to be gaining any traction for the rewinding of motors for high rpm in conjunction with large ratio reducers.


Are you developing this product? If so cool and let me be more constructive in my feedback...


toyolla2 said:


> By suggesting that a rewound 5.5Kw motor into a 12:1 ratio is subpar you are discounting a solution that could save EV'ers quite a few dollars over a 7.5Kw or 15Kw motor that they would otherwise have purchased.


If you do choose to rewind motors for higher speed, and bring a product to market a couple of things to keep in mind during product development:

Noise, harmonics and how to dampen them being transmitted to the outside world. The majority of vehicles driven on the road in significant numbers that operate in your described rpm range are high performance motorcycles. I do not know how much of the objectionable noise produced by them are exhaust/intake related or how much is mechanical. You may want to review this subtopic in your development process. This may be an issue if the com end is exposed and can buffet the air. In other words you may need a muffler if you are air cooling the com. 

Subsystem approach. If you do develop and produce a motor and controller that meets your specs, I see an issue interfacing to existing technology of current differentials. You may want to consider integrating a speed reducer on the drive end of the motor. Something that would cut the speed to a max output speed of someplace around 3k to 5k rpm would ease integration into existing donor vehicles. After sourcing high speed bearings the reducer should be a relatively easy achievement. My concern with the speed reducer is that it may eat up the cost savings recognition of the higher speed motor.

A desirable add-on within the reducer may be a lubricant circulation pump to keep the bearings lubed and cooled in both the motor and reducer.


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## toyolla2 (Jun 21, 2010)

rofl - 40Kw continuous ??

A Prius will hold 100mph - scanguage verified - with only 49 Hp which is close to 40 Kw

The DOE''s FreedomCAR (modelled after a 2006 Camry with 2.5L engineand weighing 1148kg)
SPECIFICATIONS

Its accel performance from 0 to 60mph must be under 9.3 secs

It must also be capable of climbing a 6.0% grade at 55mph
From 20% top speed its motor must maintain a peak of 55kw for at least 18 secs.

From 20% to 100% top speed the motor must be capable of a continuous 30Kw output.

BTW if a batterry drain of no more than 200 Wh/mi is specified at 60 mph, this is equiv on the flat to 12kw continuous.power.

MJ thanks for your comments. If I were to build a design I'd be doing the twin motor approsach but with the next size down from 5Kw and then have a planetary built as part of the end frame of the motor. In the case of the AT1200 it already has a diff built in - have you been on Azure's site ? 

My outlook is that LiFe batts are too expensive to waste their energy by turning mechanical power through 90 deg in a RWD or having five or six sets of meshed gears in a manual transmission needlessly churning oil when only one gearset can be in use at a time.

Lubrication should not be an issue. It looks as though the differential gear at the bottom of the geartrain will, as it rotates, carriy oil up towards the intermediate spindle where it will spill onto the larger driven gear that meshes with the motor pinion.


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## roflwaffle (Sep 9, 2008)

toyolla2 said:


> rofl - 40Kw continuous ??
> 
> A Prius will hold 100mph - scanguage verified - with only 49 Hp which is close to 40 Kw


Yuppers. A typical sedan (~3000+lbs w/ driver) will need 30+kW to maintain 60mph on a 3% grade. Faster speeds and/or grades steeper than 3% will push this to and beyond 40kW. Around here I would need at least 30+kW continuous to feel comfortable w/ traffic in a full size sedan (two ~5+ mile 3-4% grades).



toyolla2 said:


> My outlook is that LiFe batts are too expensive to waste their energy by turning mechanical power through 90 deg in a RWD or having five or six sets of meshed gears in a manual transmission needlessly churning oil when only one gearset can be in use at a time.


At least for FWD setups, it's more or less a wash with direct drive setups at lower voltages unless someone has a lot of flat ground to cruise on w/o interruptions. Transmission efficiency increases by ~3-5%, but motor efficiency drops because of the need for greater torque compared to having multiple shorter gear ratios to choose from. I don't think either of those is a deal killer, but IMO the best thing about a multispeed setup is greater power at lower speed ranges.


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## MJ Monterey (Aug 20, 2009)

Toyolla2,

I respect your goals and they are worthy. Something to consider..... 

Others will not be converting a vehicle as aerodynamically clean as a Prius. The Cd for the glider car may have significantly more drag.

Now a legitimate question. You are asserting that a ring and pinion gear drive is less efficient mechanically than the type of gear sets that are used in front wheel drive vehicles. Can you point me toward some documentation for this? I ask because I will be building from scratch and am trying to decide between 4 choices:
1) Keeping the sc300 diff and using 2 of three speeds in a converter-less automatic (t350 or C4)
2) Going to a Ford 8.8 from a Thunderbird w converter-less Powerglide
3) narrowing a front diff housing from a Toyota IFS 4x4 also w/PG
4) trying to fit a Front wheel drive diff into the back of the car (MR2 style).


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## tylerwatts (Feb 9, 2012)

Hi folks

Reviving an old thread. Does anyone have info on the AT1200 please? I understand it is based on a Honda transmission or something. Anyway, I want to know whether I can get gears to alter the ratios to get a bit more top speed. Is this an option?

Does anybody know who actually manufactured the AT1200 transaxle please?

Thanks!


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## TheSGC (Nov 15, 2007)

tylerwatts said:


> Hi folks
> 
> Reviving an old thread. Does anyone have info on the AT1200 please? I understand it is based on a Honda transmission or something. Anyway, I want to know whether I can get gears to alter the ratios to get a bit more top speed. Is this an option?
> 
> ...


I've also been wondering who actually made the AT1200. I have one with an AC24LS that I just haven't gotten out of the box yet due to life, but now that I'm snowed in I might finally get things out and start playing. I'm going to compare the differential with my Civic's and see if they take the same axles.


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## tylerwatts (Feb 9, 2012)

SGC that was my next question, do civic drive shafts fit. Then I want to know if I can regear the trans with civic diff gears. Please let us know what you find. Want to play with mine this weekend also! Maybe disassemble one to see what part numbers I can find...


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## LotusEV (Sep 8, 2012)

You guys are discussing exactly what I need to know right now.

My AT1200 gearboxed EV which was built by EVII (unfortunately, gone) has a snapped half-shaft and to figure out replacements I need to figure out what fits in the splines on the AT1200, have you discovered if indeed the Civic half-shafts fit? (if so, which year civic, if it matters)

It would be awesome to figure this out so I can get this sucker repaired and back on the road.

THANKS in advance!


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## tylerwatts (Feb 9, 2012)

Attention attention! 

The Daewoo / Chevrolet Matiz (little European car) drive shafts inner CV cup and spline piece is a perfect fit for the AT1200 transmission. And because these cars copied alot of Japanese mechanical parts I bet the civic and other shafts fit also! Trick is finding who made the gearbox in the Matiz and what else that was fitted to. This gives a wide range of drive shaft choices to mix and match lengths and wheel end stub shafts for various conversions. 

I found out by hauling my AT1200 to a breakers yard and trying anything that looked like it fitted. I'm starting a thread on my build soon if anyone is interested but will keep info specific to this drive combo here as I'm chucking 2 into my build. EV awd...


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## z_power (Dec 17, 2011)

Matiz evolved from Tico, Tico is a clone of Suzuki Alto, maybe some Suzuki parts could fit?


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## tylerwatts (Feb 9, 2012)

Probably a whole bunch of small fwd vehicles fit. Remember most gearboxes are made by a gearbox manufacturer not the vehicle manufacturers so the same is used in a number of different vehicles.


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