# Curtis 1238-144v



## JRoque (Mar 9, 2010)

Hey Cruisin, thanks for keeping us updated. What do you know about the new motor? Anything special in that and how is it better than the AC-51?

I really hope those 550A turn out to be 650A instead. Perhaps they're derating to 550A for air cooled but it can do more with water cool? There's new FETs out there that can certainly put out the current if properly cooled. 

The new system will likely cost more (as it should), plus more cells which cost more and adds more connections and weight for nearly about the same total power as the current package. I can't see that many jumping on that bandwagon. 

JR


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## cruisin (Jun 3, 2009)

JRoque said:


> Hey Cruisin, thanks for keeping us updated. What do you know about the new motor? Anything special in that and how is it better than the AC-51?
> 
> I really hope those 550A turn out to be 650A instead. Perhaps they're derating to 550A for air cooled but it can do more with water cool? There's new FETs out there that can certainly put out the current if properly cooled.
> 
> ...


The changes in the AC-51 motor are for the increased voltages only. Maybe after some time to evauluate the 144v controller, Curtis may up grade the output to 650a. Personally, the 100amp differance doesnt mean much to me, but do like the higher voltage for additional range, assuming the same size cells are used.


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## Tesseract (Sep 27, 2008)

gottdi said:


> ...Amperage ability is a big deal. Minimum of 650 is very important. 550 amps is just OK. ...


Just like with DC motors, you can wind AC motors to deliver more torque per amp with the tradeoff that they will then require more volts per RPM (frequency per RPM remaining the same).

So if a new motor is wound specifically for this higher voltage controller then the main benefit of the combination will be a higher RPM at which constant torque can be maintained (ie - more peak power); in existing installations, though, where the pack voltage and motor are already fixed, this controller will deliver less overall power.


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## Coulomb (Apr 22, 2009)

Tesseract said:


> ... in existing installations, though, where the pack voltage and motor are already fixed, this controller will deliver less overall power.


Well, yes, if you don't increase the pack voltage, and just reduce the controller current, you will deliver less power.

But what I suspect a lot of people want to know is, what happens if you change controller and also increase the pack voltage. Now you are getting less (55/65 ~= 84%) torque at low speeds, but it will stay at that level for longer, i.e. to a higher RPM. The RPM level would be about 144/108 higher (176/130? We don't know the exact numbers yet), but call it 35% higher RPM. 1.35 * 0.84 ~= 1.13, so that's a little more peak power. [ Edit: the final increase in peak power will depend on the exact specifications, and we don't have those yet. ]

With the new motor, with its higher torque per amp and higher volts per RPM, the torque curve would be more like before. [ Edit: except that the torque would start dropping at about 13% higher RPM. ] Assuming the AC-50 doesn't explode or arc over with the higher than designed voltage (I can't see any problem at less than say 400 VAC), it seems to me that the AC-50 would behave like the new motor but at a "half a gear higher".[ Edit: strictly: "half a gear taller". ] So if you normally drive in third, with the new controller and a higher voltage pack (someone suggested 13 more LiFe cells), it would be like driving the new motor in a ratio roughly half way between third and fourth gear. [ (65/55)^2 = 1.40 = about the ratio between 3rd and 4th on most 5-speed gearboxes. ]

In some conversions, you might find say third a little low and fourth a little high, so this could be even better than the new motor. Conversely, if you find say third gear just perfect most of the time, then you might benefit from upgrading to the new motor. Similarly, in a vehicle with the existing 1238 controller and AC-50, if you find yourself wishing you had a gear between 2nd and 3rd, you might benefit from switching to the new motor, *without* changing your pack voltage or controller. In other words, by using the "mismatched" motor and controller/pack combination, you get the effect of a "half gear" change.

But most people say that they don't change gears much, there is no need. So the benefit of being able to change the "overall ratio" by ~ 18% is presumably not that high. So I wonder if the newer motor development was really necessary. Comments welcome.


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## JRP3 (Mar 7, 2008)

Tomofreno talked to HPEVS and they said it was only going to be 500 amps max current, Jack Rickard said the same thing in last weeks show. Are you sure it's actually going to be 550 amps max?


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## cruisin (Jun 3, 2009)

JRP3 said:


> Tomofreno talked to HPEVS and they said it was only going to be 500 amps max current, Jack Rickard said the same thing in last weeks show. Are you sure it's actually going to be 550 amps max?


I am trying to determine your needs to find out if a product under development, not yet released, will be sold as a 500amp or a 550amp. What is your point? Do you have nothing else to do but to come up with this crap each and every time? Who cares? You seem to have a need to locate and prove something is wrong with some minor detail that somebody has posted. How about removing yourself from threads where I am trying to work with and help people without your interferance.


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## JRP3 (Mar 7, 2008)

I'm trying to get accurate information, for me and others. Why are you so upset about that? The data you provided is in conflict with data others have provided. I'm interested in the higher voltage controller, but if it's lower current than my existing one it provides no benefit. If you don't like to be questioned by me or anyone else I suggest you leave this forum. You won't be missed.


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## cruisin (Jun 3, 2009)

JRP3 said:


> I'm trying to get accurate information, for me and others. Why are you so upset about that? The data you provided is in conflict with data others have provided. I'm interested in the higher voltage controller, but if it's lower current than my existing one it provides no benefit. If you don't like to be questioned by me or anyone else I suggest you leave this forum. You won't be missed.


Others being who? The emails I get about you dont support your statement. You would be missed, for the better. You need to get a life off the farm. This is not to be mean, just a supported observation.


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## JRP3 (Mar 7, 2008)

I've gotten emails about you as well, from people who have actually met you in real life. They aren't positive, and don't paint a picture of a stable person to do business with, which your history of posting bears out. Unlike you I'm not trying to sell anyone anything.


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## frodus (Apr 12, 2008)

Stop the pissing match guys, lets keep this on topic....



From what I found out, the controller is the same size as the 1238's, so that's good. I'd likely want to watercool the new controller though.



Cruisin, 
want to maybe edit the first post and add a bulletted list of features we know are true?


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## JRP3 (Mar 7, 2008)

I'm just responding to his attitude. This is not a "you guys" issue, it's him going off script like a nut, as he has countless times in the past. I asked a simple question and he took it as a personal attack, just as he has in the past.


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## JRoque (Mar 9, 2010)

Hi all. Looks like Cruisin got banned. IMHO, I think we pull that banning trigger too easily. Having counterpoints and even "attitudes" is part of life.

Anyway, back on topic. There are MOSFET devices available right now that can handle the nominal 144V and 650A peak (with some paralleling) that we all want. These will probably fit the same footprint of those being used now on the current 650A model. That's probably why the casing looks about the same for the newer model even when it can do the higher voltage. I really hope Curtis/HPEVs keep the 650A output.

I also hope water cooling is an option in the new package so we can brew our own or buy it separately with the idea of saving some money. 

I'll leave it there; that's enough baseless speculation for now... 

JR


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## Tesseract (Sep 27, 2008)

JRoque said:


> Hi all. Looks like Cruisin got banned. IMHO, I think we pull that banning trigger too easily. Having counterpoints and even "attitudes" is part of life.


Since I've been a member here exactly 3 people have been banned: "James Morrison", "Dan Fredericksen" and "cruisin". No comment on whether those people deserved to be banned or not, just pointing out that 3 people banned in 3.5 years isn't exactly what I would characterize as an itchy trigger finger on the part of the mods... 



JRoque said:


> Anyway, back on topic. There are MOSFET devices available right now that can handle the nominal 144V and 650A peak (with some paralleling) that we all want. These will probably fit the same footprint of those being used now on the current 650A model. That's probably why the casing looks about the same for the newer model even when it can do the higher voltage. I really hope Curtis/HPEVs keep the 650A output.


I doubt the current/voltage limitations are the result of not choosing the right components and are, instead, more likely from EMI issues. Higher voltage means higher dV/dt means higher E-field radiation, the sum total of which is that high-impedance circuit nodes start acting goofy. Higher current means higher dI/dt means higher H-field radiation, the sum total of which is that low impedance circuit nodes start acting goofy.

I ran into a similar problem with the main control board in the Shiva. The same board works perfectly fine in the Soliton1 and Jr both because of the lower voltage and current, but in the Shiva it started acting funny and that required quite a bit of work on my part (and no small amount of luck!) to correct. The 1238 is a quite-compact design for the power level it delivers and it may just be that they've reached the limit of the design's EMI tolerance.

Still speculating, of course, but that's my armchair engineering opinion. Worth price paid, etc...


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## JRP3 (Mar 7, 2008)

JRoque said:


> Hi all. Looks like Cruisin got banned. IMHO, I think we pull that banning trigger too easily. Having counterpoints and even "attitudes" is part of life.


Crusin had plenty of similar episodes and was given plenty of latitude. At some point the negative outweighs the positives and just becomes disruptive.


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## DIYguy (Sep 18, 2008)

JRP3 said:


> Crusin had plenty of similar episodes and was given plenty of latitude. At some point the negative outweighs the positives and just becomes disruptive.


+1 here. Mostly spamming for sales, and attacking for little reason.


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## Bowser330 (Jun 15, 2008)

Image of 144V controller on the HPEVS website, Scion build project page.


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## JRP3 (Mar 7, 2008)

I couldn't help but notice this on the HPEVS site:


> *It is our understanding that there are AC-31 motors and Curtis controllers(1238-6501) listed on ebay.* *The listing states that the motor is capable of attaining 70 horsepower. **THIS INFORMATION IS INCORRECT.* *The AC-31 motor was originally designed to run at 72 volts and at 550 amps (Curtis controller 1238-6501) and produces 32 horsepower. This design was for vehicles under 3000 pounds at 25 miles per hour.*
> 
> *Some have had success with this set-up in light weight highway vehicles.*
> 
> ...


http://hpevs.com/catalog-ac-31-ebay.htm

Guess which banned former DIY EV member is behind this little deception? 


> *Should you have any questions regarding this listing, ntact seller.at 925.292.8565 Pictures of motor installation in a VW available from seller by emailing cruisin at live.com*


http://www.ebay.com/itm/Motor-NEW-A...version-130-ft-lbs-Torque-70-HP-/181119423725


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