# which motor should I use



## davidwillis (Feb 10, 2014)

I also forgot to mention, a pro to the ac-51 is regenerative braking. However this is not too important to me since I don't go over hills, and only stop a few times on my normal drive. But still it is nice to have.


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## onegreenev (May 18, 2012)

I would not use the Kelly controller. Better if your on a budget and want a good proven controller is to get your hands on a Synkromotive controller. Or if you need a super heavy cool looking one you can go with the Soliton. I say the Synkro for cost, weight, ease of use and no expensive cooling to deal with. It is also good for peak 900 amps and will go all the way to 192 volts if needed. The motor should be OK. 

If you go with the AC setup I'd go with the AC-75 because of the size of vehicle you have. 

Lots of folks are actually moving to AC instead of DC but DC still reigns supreme for grunt and cost but AC is closing the cost factor if you go with the HPEVS setups. It also does REGEN with no issues. DC regen is not recommended. 

Pete


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## davidwillis (Feb 10, 2014)

Thanks for the comments, and controller recommendations.

I was looking into the ac-75 or 76, but they don't have the option to be vented, and the continuous power is only about 15 hp, which is a lot less than the ac-51 with vented cooling, and seems too low. Am I missing something with this?


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## Ivansgarage (Sep 3, 2011)

davidwillis said:


> Thanks for the comments, and controller recommendations.
> 
> I was looking into the ac-75 or 76, but they don't have the option to be vented, and the continuous power is only about 15 hp, which is a lot less than the ac-51 with vented cooling, and seems too low. Am I missing something with this?


Where did you come up with those numbers? Horse Power.

Here is charts and numbers.

http://ivanbennett.com/forum/index.php?topic=132.0


Ivan


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## davidwillis (Feb 10, 2014)

go to http://www.hpevs.com/power-graphs-ac-75.htm

The click on.

AC-75 
Imperial
144 Volt
Continuous Graphs

Then click on the graph.

The data given in that link is for max instantaneous power, but not continuous.


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## onegreenev (May 18, 2012)

Guess I was not clear on this either. Thanks Major. I see. Still I don't see this graph as any thing very important. The importance is what kind of power you can expect from the setup. You see, you don't drive at one speed all the time. So knowing what it will do is what is needed mostly. For the size vehicle, the AC-75 should provide a much better motor. My earlier post about the cooling stands. 

I'd go with the AC-75. 

Call up HPEVS. They will help you understand. 

If you ever have questions about a product it is best to first ask the company that makes them. They know best.


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## major (Apr 4, 2008)

davidwillis said:


> Thanks for the comments, and controller recommendations.
> 
> I was looking into the ac-75 or 76, but they don't have the option to be vented, and the continuous power is only about 15 hp, which is a lot less than the ac-51 with vented cooling, and seems too low. Am I missing something with this?


That's the way I read this:











Actually about 12 hp at 2000 RPM for continuous power output. Seems about right for a TENV motor of that size.


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## davidwillis (Feb 10, 2014)

onegreenev said:


> Guess I was not clear on this either. Thanks Major. I see. Still I don't see this graph as any thing very important. The importance is what kind of power you can expect from the setup. You see, you don't drive at one speed all the time. So knowing what it will do is what is needed mostly. For the size vehicle, the AC-75 should provide a much better motor. My earlier post about the cooling stands.
> 
> I'd go with the AC-75.
> 
> ...



That makes sense. I will ask them. However to me the graph does seem important.... Please don't take this as me arguing with you, but I just want to understand... To me that chart says that after 5 min, this motor will heat up, and not put out more than 12-15 horse power. I drive for 45 min at 55 mph, and I don't see how 12-15 hp will move a 4,000lb vehicle at 55 mph.

Also, I must have missed your post on cooling.


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## onegreenev (May 18, 2012)

Oooops. I erased it when I updated my post. I have talked to HPEVS directly and the AC-75 will not overheat. It was a concern of mine as well about the cooling. They have told me to date that the motor does not overheat. They put one in their own vehicle as well. I trust there judgment and since they have been making them for a very long time trust their work. I have saved up for an HPEVS AC-75 for my Porsche 914. Soon I will buy one. I know of a person out here in my area that has put one in his vehicle and so far its running fine. He drives the freeway to work and back every day. 

Pete 

Like I said. If you have questions it is far better to ask those that make the product before putting your question on this site. Once your question is on this site you will get a load of speculation. Talk to the makers of the motor. Don't just rely upon those here. Lots of knowledge here but its always best to go straight to the source first. Always.


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## davidwillis (Feb 10, 2014)

Thanks. That is great to know it is actually working for someone. Do you know if they did anything to cool it?

I sent an email to hpvs, and they did answer, but they didn't give much detail. Maybe I will need to call them when I have a day off.

Here was there response:

The AC-51 would be a good choice. The AC-75 at 144 volts would be a better option than the AC-76 also.

My questions:
I am looking for a Motor for a conversion for a Honda passport (curb weight 3600 lbs). I was thinking about using the AC-76, but after looking at the continuous power, it looks like it will only put out about 15 HP. This seems too low to push a 3600lb vehicle at 55 mph.

I see the AC-51 has an option for a vented motor which produces much more continuous HP. So would this mean the AC-51 is actually better for this vehicle? It is also lighter, and less money 

By the way, I plan on driving this for about 45 min at 55 mph, so I am concerned the non vented motor will not provide the sustained power.


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## evmetro (Apr 9, 2012)

I run an AC74, and have not noticed any decrease in performance due to heat. My EV is a lighter weight vehicle, but I do run it pretty hard. 100 mph occasionally, long enough to giggle, I run a lot of 6% grades! and I run it hard on twisty hilly roads in the foothills. The motor temp does indeed go up quite a bit, but I can't detect any noticeable decrease in performance. This could be simply because my vehicle is so much lighter, so I don't know how it would work on a heavier vehicle like yours.


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## onegreenev (May 18, 2012)

Any idea how hot? Could you take a measurement and log it over time? I'd be interested in seeing that myself. But mine will be in a light weight little beastie too.


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## evmetro (Apr 9, 2012)

onegreenev said:


> Any idea how hot? Could you take a measurement and log it over time? I'd be interested in seeing that myself. But mine will be in a light weight little beastie too.


The site glass displays the temp in Celsius, so I don't really have any idea how hot it gets in real American degrees. I took a spirited drive the other day that included a one mile 7 % grade and then about 3 miles of twisty foothill roads and my temps were 32 on the controller, and 70 on the motor at the end of the ride. I do remember when I ran the AC35 on this same car that the motor and controller typically ran at roughly the same temp, unless I had the water pump off for the controller and the controller would get up to 70. The AC 74 is a fun motor, but I would have to say that the AC 35 makes more sense on a 2000 pound car. It weighs 100 pounds less and does not require suspension upgrades. The price of an AC 35 or AC50 is also a bit less. While I do not regret upgrading from the 35 to the 74, I am anxious to finish the conversion that I am putting the 35 into...


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## davidwillis (Feb 10, 2014)

It is great to hear of some real world experience with these motors.

I was just looking at some prices, and I see I could go with the ac-74 with 72v for about the same price as the ac-51 with 144V. There are no continuous charts for the ac-74 with 72v but the other charts actually look like the ac-51 144 would outperform and be lighter.

I wonder how this would compare in real world driving though... any thoughts?

by the way (evmetro), was your AC-35 vented or sealed?


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## onegreenev (May 18, 2012)

That would be 158F on the motor and 89.6F on the controller. Pretty good. Yeah! I like the AC-75 but don't like the weight of the beast as compare to the AC-35 or 50. I heard recently that the dual 35 is as long as the 75. Not longer. I may consider a dual setup instead. Similar weight but much more powerful. 

Pete


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## onegreenev (May 18, 2012)

In that case the AC 51 is a better choice because it gives you more power out to a much higher RPM. I would not go with the AC 74. Things just drop off too quickly. I much rather use the AC-75 at 144 volts. Not as much torque bit it takes it out to the 4000 plus rpm range before really dropping off. I drive in the 1 to 4000 rpm range in my Porsche. Perfect.


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## tomofreno (Mar 3, 2009)

What is CdA (product of drag coefficient and vehicle cross sectional area) for your vehicle?

Do you plan to use the transmission? 

Do you know the overall gear ratios (transmission and differential) for your vehicle?

What 0 to 60 mph time do you want?

What vehicle range do you want?

How much money are you willing to spend on the conversion - batteries, motor...everything?


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## davidwillis (Feb 10, 2014)

tomofreno said:


> What is CdA (product of drag coefficient and vehicle cross sectional area) for your vehicle?
> 
> Do you plan to use the transmission?
> 
> ...


1- I don't know what the that is, but here are some numbers:
Wheelbase (in.) 106.4 
Length (in.) 184.2
Height (in.) 68.8 
Width (in.) 70.4 
Track (in., front) 59.6
Track (in., rear) 59.8 
EPA Curb Weight (lbs., MT/AT) 4013 / 4053 
Minimum Ground Clearance (in.) 8.2

2- yes I plan on using the transmission.

3- it is a 5 speed manual...
Final Drive Ratio (MT/AT) 4.3/4.1

4- I don't really care as long as it can get up to 55mph within a minute or so... obviously it would be nice to be able to accelerate at a good rate though.

5- I would like to get a 75 mile range, but absolutely need to get 65 miles. I currently have 48 200ah lithium Ion batteries for it, which I hope is enough. If not, I may need to change my plans and use a different vehicle...

6- I have the vehicle and the batteries, but I need to keep the rest at under 10k. but would obviously like to keep it as low as I can.


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## davidwillis (Feb 10, 2014)

ok, I did some calculation on range.

speed 55mph
weight 4000 lbs
coefficient of road friction 0.015
frontal area 35 ft2
coefficient of air drag = .32

Rolling force (N) = 266.7 Newtons
Air Friction force = 377 Newtons

HP required = 21.23 HP
Wh/mile = 288

Battery pack energy = 28224 kwh

Range = 78 miles to 80% DOD

So I think I should be able to get 60 miles with this.... I hope... 

I used this: http://johnsavesenergy.com/EVRangeCalc.html#.Uv2kzMMgfRZ

and put in my numbers. I don't think it accounts of how efficient the controller and motor is, as well as the drivetrain, and any power used for a heater in the winter or power stearing pump, etc.


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## davidwillis (Feb 10, 2014)

wow, look at this monster...Baldor AC motor

TEMR-50, AC, 72 Volt, 1775 RPM - $5,200.00


50 Hp @ 72-96 Volts AC - 3 Phase, 362 Full Load Amps @ 1776 RPM
Continuous Rated @ 150ft/lbs Torque
94.5 Efficiency
TENVAO (Totally Enclosed - Non-Ventilated, Air Over)
Sealed Bearings
IP54 with some IP55 Features
Brushless/Low Maintenance - Dirty Duty
Large Shafts - 1.625" OD Input and Output Shaft
Large 6312 Bearings on Both Ends
Bi-Directional Drive Shaft
Quaduature Encoder - 2 Channel
Thermisters
490 Lbs


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## PStechPaul (May 1, 2012)

davidwillis said:


> ok, I did some calculation on range.
> 
> speed 55mph
> weight 4000 lbs
> ...


I used my http://enginuitysystems.com/EVCalculator.htm with those values and at zero acceleration I get 23.2 HP and 310 Wh/mile. So that is excellent correlation. It may be best to add a little bit of acceleration or slope, unless you are driving on perfectly flat roads or you have a high percentage of regeneration. Adding 0.45 m/s^2 acceleration (4.6% slope or 1 MPH/Sec or 0-60 in one minute) requires 50 HP and 672 Wh/mile, but that will be only for a small portion of your drive, and the rest may average 1% slope, which takes 29.3 HP and 390 Wh/mile. This is what is required, not counting efficiency, which is probably 80-90%.

"YMMV"


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## davidwillis (Feb 10, 2014)

Ok, so lets say I avereage 310 Wh/mile, it will take 20,150 wh to drive 65 miles. But if I am only at 85% efficiency, it will actually take 23,173 wh which is 82% of my battery...

60 miles will use 18,600 WH, with 85% efficiency it will actually take 21,390, or 76% of my battery.


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## davidwillis (Feb 10, 2014)

ok, so back to which motor. I like the idea of a brushless ac motor, but The only one that will provide 30hp continuous is the ac-51 vented with fan cooling, And even with that, it will only do it at 4000 rpm's. I have not heard back from them on how the AC-75 would do or if I can provide cooling for it.

So I am thinking maybe a DC motor Would be better...


ME1002 - 35 HP continuous - 190 lbs - $1300

Warp11 - 32 hp continuous - 229 lbs - $2600

K11 or K11 Alpha - I am not sure about this, but I think it would be over 30 hp continuous 165 lbs - $2700 for Alpha


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## McRat (Jul 10, 2012)

GM has made a permanent magnet AC traction motor with 140HP. It "should" be fairly light. No idea how much $$$, they haven't hit the junkyards yet.


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## tomofreno (Mar 3, 2009)

davidwillis said:


> ok, I did some calculation on range.
> 
> speed 55mph
> weight 4000 lbs
> ...


 Drag coefficient of 0.32 seems low for that vehicle, but using that at 55 mph I get:

Rolling resistance = 70 lb (you estimated about 60 lb using a rrc of 0.015. I used 0.014 rrc, but added 0.003 for brake drag, total 0.017)

Drag force = 87 lb (you estimated about 85 lb)

Power = 30 H.P. or 22.4kW, for 90% drive train efficiency and 85% combined motor and controller efficiency (about 23 HP without these losses)

Wh/mile = 22400/55 = 407. 

The 144V HPEVS motors have a peak power of about 90 HP, whereas the original ice in these vehicles had 175 to 205 HP. I estimate 0 to 60 mph in about 20 sec. If that is acceptable, then you might find the HPEVS thread started by Brian in the Chat section here and post a question about motor heating at this continuous power. If you want greater acceleration, the cheapest way would be to use a larger DC motor and Soliton or Synkromotive controller. If you have space you might also consider the dual AC35. EV Propulsion, second add on the RHS of your screen has all these options to compare.

Edit: if you live in a cold climate remember to add about 25% battery capacity for cabin heating, and leave a cushion, say discharge to 30% SOC for the desired range.


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## davidwillis (Feb 10, 2014)

I think I will need a little more range... 

Looking at the motors, I think the best option would be to get a few more batteries and run the k11 Alpha at 192V (after I add another 16 batteries for a total of 64 200 ah batteries). This would add another 33% which should give me the range, and that motor would give me plenty of power.


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## tomofreno (Mar 3, 2009)

davidwillis said:


> I think I will need a little more range...
> 
> Looking at the motors, I think the best option would be to get a few more batteries and run the k11 Alpha at 192V (after I add another 16 batteries for a total of 64 200 ah batteries). This would add another 33% which should give me the range, and that motor would give me plenty of power.


That should work for range. I forgot most of your driving would be at 55 mph, so a 3kW heater would increase your Wh/mile by only 13% rather than 25%, assuming you don't get stuck in traffic. That size motor with one of the two controllers I mentioned should give you sufficient torque and power. Might check with others running DC motors at that continuous power, but I would think you should add a blower to the comm end. EVWest and others sell them. If you live in a cold climate add heaters for the batteries to avoid loss of capacity in winter - you will have a bit more drive train friction in winter too. If you can't mount the motor up high enough to avoid slush and water splashing add a belly pan under it to protect it (just needs to be long/wide enough to protect the motor from spraying slush from the wheels).


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## toddshotrods (Feb 10, 2009)

davidwillis said:


> ...I think the best option would be to get a few more batteries and run the k11 Alpha at 192V...


Nothing wrong with that motor choice, that I know of, but just to be sure you're aware (and others who may read this) - you don't have to increase the motor's voltage capacity just because you increase the pack voltage. The controller can have a higher max voltage, up to 300-400v (with Soliton, Zilla, etc) and limit the maximum voltage the motor sees to what is safe for it. The range will still be there, because the energy is still in the pack.


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## davidwillis (Feb 10, 2014)

toddshotrods said:


> Nothing wrong with that motor choice, that I know of, but just to be sure you're aware (and others who may read this) - you don't have to increase the motor's voltage capacity just because you increase the pack voltage. The controller can have a higher max voltage, up to 300-400v (with Soliton, Zilla, etc) and limit the maximum voltage the motor sees to what is safe for it. The range will still be there, because the energy is still in the pack.


Thanks. I was actually not aware of that, so it does still give me options of using the lower voltage motors, and saving a little.

Another question thought. If I use a BMS, can I use a different brand of battery in series. For example I have 48 of one brand (200 ah), can I add 16 more of a different brand (as long as they are 200 ah), or do the batteries need to be the exact same?


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## davidwillis (Feb 10, 2014)

tomofreno said:


> That should work for range. I forgot most of your driving would be at 55 mph, so a 3kW heater would increase your Wh/mile by only 13% rather than 25%, assuming you don't get stuck in traffic. That size motor with one of the two controllers I mentioned should give you sufficient torque and power. Might check with others running DC motors at that continuous power, but I would think you should add a blower to the comm end. EVWest and others sell them. If you live in a cold climate add heaters for the batteries to avoid loss of capacity in winter - you will have a bit more drive train friction in winter too. If you can't mount the motor up high enough to avoid slush and water splashing add a belly pan under it to protect it (just needs to be long/wide enough to protect the motor from spraying slush from the wheels).


Thanks, great suggestions! My commute is about 45 min each way(30 miles each way), so my average is not 55, but I drive at 55 for a lot of it. I have also heard you need to keep lithium ion batteries above freezing when you charge them to avoid damage, so the battery heaters will be important.

Also if I go with the k11 alpha, it has a blower on the motor, do you think it needs more than that?


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## tomofreno (Mar 3, 2009)

It is best to have the batteries (cells) well-matched in capacity and internal resistance but people have mixed cells without problems. You are of course limited by the lowest capacity cell in a series string.

I would guess the blower that comes with the motor would be sufficient, but am not familiar with it. Maybe someone else here is. You could check with a manufacturer representative, or maybe find info on the manufacturer's website.

You can set a limit on motor voltage with the microprocessor controlled motor controllers like Synkromotive or Evnetics, but not the cheaper analog ones.


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## davidwillis (Feb 10, 2014)

I finally got another reply back from hpevs.

Here is the question I asked this time:

I have been doing some calculations, and with this weight of vehicle I will need around 30hp continuous to keep it going at 55 mph. The Only motor I see that will do that is the AC-51 vented with fan. And that will only happen at above 4,000 rpm's.


Is there a way to provide cooling to the AC-75 so I can get a sustained 30hp?



And the answer:
You may want to look at the AC-34x2 or the AC-35x2.

To be honest, I am not really impressed with there help.

So I think I like the option of going with the k11-alpha.


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## davidwillis (Feb 10, 2014)

So looking at the k11 alpha, it does not look like it comes with an auxiliary shaft. I need to have something to run my power steering, power brakes, and my AC pump (this is not critical, but would be nice).

I see I can get these as separate devices, but since I already have a power steering pump, and AC pump, I would rather not pay the extra money to buy new ones. Could I just mount a small motor with some belts to run these pumps?

buying them separate:
Power steering: $920
vacuum pump: $388
AC $900


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## davidwillis (Feb 10, 2014)

I am still looking at my options here. I can't help but like the idea of an AC motor, however if I go up to 192v, the controller will not handle that much voltage... The only thing I can think of is to run the two packs in parallel and run it at 96 volts.

I am just wondering if there are any other options, or any AC controllers that will handle 192v like the DC controllers do.


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## toddshotrods (Feb 10, 2009)

davidwillis said:


> ...I am just wondering if there are any other options, or any AC controllers that will handle 192v like the DC controllers do.



 Sevcon
Tritium
Rinehart
 There's a guy selling an RMS drive in the classifieds here.


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## tomofreno (Mar 3, 2009)

You won't be happy with performance if you use 96V.

EVWest (advertisement on the RHS of your screen) seems to have the most offerings in AC motors and controllers. The Sevcon Gen4 Size8 will handle the 192V, but you will be limited in power output with that voltage due to its peak 400A. EDIT: Same issue with the RMS in Classifieds. It's peak current is 350A. Most of the AC controllers are made to operate at higher voltage/lower current compared to the Curtis controllers used with the HPEVS motors. You have to use a higher voltage pack to get more power output from them.


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## davidwillis (Feb 10, 2014)

I guess those are not cheap, since the one for sale is $4500 plus shipping.


What are your thoughts on this:

Siemens 1PV5135-4WS14-Z Motor
Azure Dynamics Force Drive DMOC 645 Inverter


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## davidwillis (Feb 10, 2014)

tomofreno said:


> You won't be happy with performance if you use 96V.
> 
> EVWest (advertisement on the RHS of your screen) seems to have the most offerings in AC motors and controllers. The Sevcon Gen4 Size8 will handle the 192V, but you will be limited in power output with that voltage due to its peak 400A. EDIT: Same issue with the RMS in Classifieds. It's peak current is 350A. Most of the AC controllers are made to operate at higher voltage/lower current compared to the Curtis controllers used with the HPEVS motors. You have to use a higher voltage pack to get more power output from them.


I think 400A at 200V is enough power for me. I am more worried about the price of the controller. I can't see any of the SEvcon contorllers at EVWest, but I see the Rinehart controllers.


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## davidwillis (Feb 10, 2014)

So I have decided to go with the Siemens 1PV5135-4WS14-Z Motor
and the Azure Dynamics Force Drive DMOC 645 Inverter. The price was good, and I like the motor (plenty of power and liquid cooled), the only thing that worries me is that there is no warranty or support for them....


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