# setup of a curtis controller with a sepex motor



## major (Apr 4, 2008)

colt said:


> Hi i have a 48volt curtis controller (1244can) running a sepex motor. Using the d&d motor performance chart at 2000 motor rpm i should get 10hp with 45ft torque. With these numbers and the correct ratio i should be able to maintain 60kmh. But all i can do is 50kmh. So my question is :
> Has anyone ever setup one of these controllers?
> Am i missing something basic?
> Any help would be grateful


Hi colt,

I've used a couple of these 1244s. With D&D motor. Not sure the motor you have is the same. But 45 lb.ft. is a bunch. On mine, like 300 to 350 amps. So you get a bit of sag from the battery (lower voltage). Puts my RPM down in the 1600 RPM range. I suspect you expect too much from this set up. What size vehicle do you have?

Regards,

major


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## Guest (May 21, 2009)

Use the field weakening function if it allows you to program that parameter or if it even has it. Hoping it has it and you can program it for use. It would help once at full throttle.

Pete


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## major (Apr 4, 2008)

gottdi said:


> Use the field weakening function if it allows you to program that parameter or if it even has it. Hoping it has it and you can program it for use. It would help once at full throttle.
> 
> Pete


Hi Pete,

That ain't going to do it. Field weakening works at light loads, but he is way out there. On this size motor, I bet field weakening would make it go slower, and draw more current.

This is a common misconception about field weakening. Yeah, it increases RPM at a given armature current. But it also decreases torque for that armature current. So, for light loads (torque), the RPM and current both increase as the field decreases. But at the high torque values, the increase in current due to weakening the field adversely affects the generated voltage and you see a decrease in RPM.

That is why these SepEx controllers have the field map programmed into them. I seriously doubt that the program would allow parameter settings for weak field up at 300 or 400 amps, where colt is at 45 lf.bt.

Regards,

major


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## DavidDymaxion (Dec 1, 2008)

Go to the Curtis web site, and you can download the 1244 manual. There are parameters like max field, min field, and the field map parameters you can program. The manual also gives tips on how to program your motor. I too have a 1244, so I'd like to hear about your results with it.

As major said, there is an optimum field current value to get the most torque at that rpm. If you continue to weaken past that point you'll not only get less torque, you'll also increase the possibility for arcing and motor damage. You might already be at the best point.


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## DavidDymaxion (Dec 1, 2008)

Yep, free, just download it.


fullhouse said:


> do they give it for free? I guess they should give manual upon purchasing it.


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## tj4fa (May 25, 2008)

The manual and data sheet are downladable on this link down the page:

http://curtisinst.com/index.cfm?fuseaction=cProducts.dspProductCategory&catID=9


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## anand.ssukhi (Jul 23, 2009)

iam going to use the same controller can u please tell me the motor and battery pack details also please tell me the range u r getting with the battery pack


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## anand.ssukhi (Jul 23, 2009)

also please tell me what is the voltage it gives to feild winding


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## major (Apr 4, 2008)

anand.ssukhi said:


> iam going to use the same controller can u please tell me the motor and battery pack details also please tell me the range u r getting with the battery pack





anand.ssukhi said:


> also please tell me what is the voltage it gives to feild winding


Hi anand,

If you choose the controller first, then you have to find a motor compatible with it, ie. a Separately Excited (SepEx) motor. Then your battery pack voltage must conform to the specified controller input. The Ampere hour (Ahr) rating will determine range. It is up to you to choose that.

The field voltage varies according to the motor (set-up in the controller parameters) and the actual load on the motor. The controller takes care of all that once you have it set up.

Regards,

major


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## anand.ssukhi (Jul 23, 2009)

i have ordered for an 48 v(armature)and 18-24v(feild) motor
it has an torque rating 45 Nm at 1500rpm.
we are going for a 48 v 160Ah battery we are expecting a max of 50kmph and our vehicle weighs abt 700 kg unladen & it is 2 seater so please give us the details abt what range i should xpect.


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## yarross (Jan 7, 2009)

major said:


> Field weakening works at light loads, but he is way out there. On this size motor, I bet field weakening would make it go slower, and draw more current.


I feel I have to disagree 
Actually, field weakening allows at certain RPMs above base speed (the speed at which the current falls below the motor current limit due to BEMF) to get MORE torque. This means wider operating range, but... if you still have your transmission (and you're willing to shift gears), there's no much gain from field weakening. It's critical in single-speed systems anyway.


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## major (Apr 4, 2008)

yarross said:


> > Originally Posted by *major*  _Field weakening works at light loads, but he is way out there. On this size motor, I bet field weakening would make it go slower, and draw more current._
> 
> 
> I feel I have to disagree
> Actually, field weakening allows at certain RPMs above base speed (the speed at which the current falls below the motor current limit due to BEMF) to get MORE torque. This means wider operating range, but... if you still have your transmission (and you're willing to shift gears), there's no much gain from field weakening. It's critical in single-speed systems anyway.


Hi yarross,

Give it a try and let me know how it works out for ya 

major


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## anand.ssukhi (Jul 23, 2009)

the motor says 
power: 3.2 kw
rpm: 3200
please tell me the torque rating I should expect
also the armature is rated 48v, 90 amp
and field 18v


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## yarross (Jan 7, 2009)

anand.ssukhi said:


> the motor says
> power: 3.2 kw
> rpm: 3200
> please tell me the torque rating I should expect


If those two values occur simultaneously, 9.55Nm (7.04lbft)


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## anand.ssukhi (Jul 23, 2009)

yarross said:


> If those two values occur simultaneously, 9.55Nm (7.04lbft)


thanx its peak current goes 300 amps please tell me what peak torque I should expect
and also what max rpm it can go by field weakning


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## yarross (Jan 7, 2009)

anand.ssukhi said:


> what max rpm it can go by field weakning


Up to centrifugal stress and/or commutator limit, but keep in mind that above base speed (where the field weakening kicks in) the torque will gradually fall, so the max speed may be determined by load increasing with speed.


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## anand.ssukhi (Jul 23, 2009)

I am using an curtis 1244 controller and Iam unable to figure out how to use the regen feature. there is no input for break pedal it only says abt automatic braking when u leave the throttle


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## Guest (Feb 9, 2010)

Does not look like it has parameters or connections for a brake switch type braking. Looks like only throttle off braking. Pop your foot off the throttle and it brakes. Do it fast and you brake hard. Do it slow and you brake slow. You still need manual brakes. Looks like there is loads of parameters you can set for the braking and fields. Nice. Sorry but I think you may have to have a different controller if you wand pedal braking. The controller is more for carts and such. Not an on road car. 

Pete


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