# New AC motor system from HPEVS



## JRP3 (Mar 7, 2008)

Brian from HPEVS mentioned that they are considering doing a siamese AC motor system using two Curtis controllers and a dual AC 35 stator setup. They are trying to figure out how much demand there might be for such. General specs from Brian:



> we had a meeting this morning about building a dual siamese motor, like in the Jetta. This would have two of the AC35 stators and rotors, on a common shaft, in a single housing. I want to get some feedback and see if you think there would be interest out there for it. Preliminary power would be 190 Ft lbs of torque, 130 HP running on 144 volts. Base speed will be around 4500 RPM, so its going to pull to pretty high RPMs.





> We should have an outline drawing in a few days. I think it will be 20" long though. Weight around 150 pounds. Retail price point for the whole system should be around $9000.00.
> 
> It can use the new 144 volt 500 amp, 96 volt 650 amp or 72 volt 550 amp.


It should look a little something like this 










Anyone interested, speak up


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## JRP3 (Mar 7, 2008)

Looks as if they already have a web page up about it:
http://www.hpevs.com/dual-siamese-motor.htm


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## njloof (Nov 21, 2011)

Image is broken for me. But interested!


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## JRP3 (Mar 7, 2008)

I guess they didn't like the hot link. Look through the gallery here:
http://www.hpevs.com/jetta-photo-gallery1.htm


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## Nathan219 (May 18, 2010)

If you are using one controller, do you have the ability to use a stator which goes the whole length of the motor instead of two smaller stators? If you are using two controllers then never mind the first question. HPEVS is one of the few companies talking to the Ev community, for that, I thank you. 
I have been researching torque motors which use larger diameter and lower RPM, like Yasa motors, and think they are the best choice for direct drive applications. The problem I am finding is that there is not one designed for the RPM and torque range for a direct drive application in an EV under ~$20,000. What I want and think would be Ideal would be a 50nm torque at 1000rpm that should be able to push most cars down the road at 65 mph using two motors; a peak torque should be at least 4 times that for acceleration. The thermal dissipation should be for the 50nm continuous power. Also it would be nice if the motors were modular so you could stack them easily to increase performance. That is my wish list!


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## Yabert (Feb 7, 2010)

Nathan219 said:


> I have been researching torque motors which use larger diameter and lower RPM, like Yasa motors, and think they are the best choice for direct drive applications.


I strongly agree!

Dual direct drive motor with high torque and low speed (relatively 0-1500 rpm) and reverse/regen capability is way more interesting!... especially when you can currently buy a DC system able to output more than 130 hp and weighting less than 120 lbs for 3600$ (soliton Jr / Kostov 220).

A dual direct drive motor is simple, weigh less, is more efficient.... we all waiting the perfect motor/controller combo at decent price..


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## ev-converter (May 24, 2012)

Yabert said:


> I strongly agree!
> 
> Dual direct drive motor with high torque and low speed (relatively 0-1500 rpm) and reverse/regen capability is way more interesting!... especially when you can currently buy a DC system able to output more than 130 hp and weighting less than 120 lbs for 3600$ (soliton Jr / Kostov 220).
> 
> A dual direct drive motor is simple, weigh less, is more efficient.... we all waiting the perfect motor/controller combo at decent price..


Your comparison of costs are unrealistic. AC comes with all wiring and necessary guages, DC doesnt. AC requires less cells which really saves money. I did a dual AC-35 with 2-Curtis 650a controllers. one slave and one master in a boxster. AWESOME in power. Dual drive on single shaft is not going to work for most conversions, too long. Belt drive works best.


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## marc02228 (Jan 15, 2011)

hehe, I asked them for exactly that siamese motor, nine days ago


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## ruckus (Apr 15, 2009)

Well, I'm all for an inboard dual direct-drive set-up, BUT....

"...Preliminary power would be 190 Ft lbs of torque, 130 HP running on 144 volts. Base speed will be around 4500 RPM, so its going to pull to pretty high RPMs.
... Retail price point for the whole system should be around $9000.00"   

He better run a few basic calcs before building his planned system (or talking about it) as it would NOT WORK at all. His torque and rpm numbers are WAY off.

As others pointed out, 1500rpm is the max needed (good for over 110mph!!). 4500rpm is just plain ridiculous and shows he hasn't even done the basic math or doesn't understand the mechanical components and forces required to make a car go. 

Even the weakest cars ever made have about 100ftlbs x 3.5tranny x 3.5differential = 1200ftlbs MINIMUM. Even if you half that you still need 600 ft lbs.

190ft lbs won't get you out the driveway (if it is uphill).


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## JRP3 (Mar 7, 2008)

I don't know where this got off the rails with a dual motor direct drive system. This is meant to be used with a transmission or at least a gear reduction, just like all the other HPEVS systems. Let's try to stay somewhat on topic.


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## ruckus (Apr 15, 2009)

JRP3 said:


> I don't know where this got off the rails with a dual motor direct drive system. This is meant to be used with a transmission or at least a gear reduction, just like all the other HPEVS systems. Let's try to stay somewhat on topic.


Golly, sorry. Without a working picture, and all the posts talking about direct drive, that seemed like what the product was.

Ok, so now that I understand the proposal, I have a different critique. 

1. Why buy two controllers? Where is the advantage in that? (unless they are very unreliable).
2. 190ftlbs is still awfully weak in today's market and ESPECIALLY considering...
3. You can buy 3x the motor for 2/3 the price elsewhere.

I just don't see any advantage to low-voltage AC. High-voltage, yes... IF the price comes down to reasonable ($5-7,000 for motor and controller).

Cheers


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## Yukon_Shane (Jul 15, 2010)

This new design is definately interesting but the price is too high to make me seriously consider it; not when you can buy a warp 9/kostov and a soliton junior combo for under $4k. 

The extra $5k for this system would buy alot of batteries...


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## kerrymann (Feb 17, 2011)

I would be interested but at a price point is too high. 6-7k yes but 9k just doesn't give the price performance ratio.


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## somanywelps (Jan 25, 2012)

ruckus said:


> As others pointed out, 1500rpm is the max needed (good for over 110mph!!). 4500rpm is just plain ridiculous and shows he hasn't even done the basic math or doesn't understand the mechanical components and forces required to make a car go.


Differential gear down....


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## JRP3 (Mar 7, 2008)

ruckus said:


> Golly, sorry. Without a working picture, and all the posts talking about direct drive, that seemed like what the product was.


I did provide a working link.
To your questions:


> 1. Why buy two controllers? Where is the advantage in that? (unless they are very unreliable).


This is essentially two motors in one housing, the Curtis AC controllers, which seem very reliable, are limited to 144V and 500 amps, so you need two to get enough power.


> 2. 190ftlbs is still awfully weak in today's market


It's almost twice what the popular AC50 provides


> 3. You can buy 3x the motor for 2/3 the price elsewhere.


The jury is still out on that if you are talking about an AC system, but if it's true then yes that's a good point.


> I just don't see any advantage to low-voltage AC


Easier to configure and manage a pack.

Obviously this is not an ideal setup, but I guess HPEVS has not found an affordable controller other than the Curtis that works with their motors.


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