# Curtis controller 1238-7501



## major (Apr 4, 2008)

licc said:


> Hi. We are doing a project on HPGC AC 50 motor and Curtis controller in 1238-7501. Mode controller is installed in Torque Mode. At startup, the controller limits the current 70A, and the car does not drive. We can not switch the other modes. The programmer we have. Why a low starting current?


Hi li,

I have found that you cannot switch from torque to speed mode due to the way the controller was tuned to the motor from the place where you bought the package. But you need to use torque mode anyway.

You should try driving the motor with the controller with an empty shaft first to see if you have all the connections correct. Once you verify that the controller and motor work properly at no load, couple it to the vehicle driveline and try it with the wheels jacked off the ground. Once you have the wheels spinning freely, set it down and go for a ride 

Report back.

major


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## licc (Aug 14, 2011)

Thank you. Yes, we tried to turn the motor with an empty shaft and on the road. Everything is OK. but very slow acceleration. initial current 70A.


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## frodus (Apr 12, 2008)

Check to see if you're in limp mode because your battery SOC is 0%.

sounds like you're voltages aren't set correctly for the vehicle. Every time I see this it's because the battery voltages aren't set up correctly and they're not able to go very fast.

I can help if you need, email me below.


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## major (Apr 4, 2008)

licc said:


> Thank you. Yes, we tried to turn the motor with an empty shaft and on the road. Everything is OK. but very slow acceleration. initial current 70A.


I assume you bought the AC50 package from someone. Ask them for help first.

If you can't get the motor to spin up at a good rate at no-load, it won't do well in the car. You need to check your inputs and parameter settings. But torque mode is correct.

major


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## licc (Aug 14, 2011)

frodus said:


> Check to see if you're in limp mode because your battery SOC is 0%.
> 
> sounds like you're voltages aren't set correctly for the vehicle. Every time I see this it's because the battery voltages aren't set up correctly and they're not able to go very fast.
> 
> I can help if you need, email me below.



Thank you. Our battery of 36 cells 90ah Winston. the battery is fully charged. In the mode 'Torque Mode' the motor must give maximum torque at 0 rpm (on the graph http://www.evparts.com/cms/picts/products/MT5615 Torque.PDF )?


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## frodus (Apr 12, 2008)

I realize that you're in torque mode, that isn't the issue. The issue is that your controller is limiting the current for some reason. I'm trying to get you to help me figure out why.


What is the SOC inside the curtis displaying? if it's not 100%, then you havent set it up correctly and the controller is being forced into Limp mode.


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## major (Apr 4, 2008)

frodus said:


> I realize that you're in torque mode, that isn't the issue. The issue is that your controller is limiting the current for some reason.


Or he's not getting the command signal. Is the throttle pot set correctly and is the pot functioning properly?


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## frodus (Apr 12, 2008)

Could be that, but on the systems I've worked with, almost every time they haven't set up the battery correctly on the programmer and it runs in limp mode if it sees the SOC as too low. Throttle could be it too, but SOC is an easy one to look for first if they have the programmer. HPEVS has something in their VCL code that limits the controller if you're below a certain SOC (BDI percentage).

First, get yourself the curtis manual from me:
www.evfr.net/uploads/123468_manual.pdf

Go to the monitor menu on the programmer (page 64). Go to "battery", then look at BDI percentage. If it's a really low number (probably 0%), then that's probably it.


The issue with most conversions I've seen, is when you want to use 36 cells and haven't set up the batteries. It's almost a given. It's up to the user to change those settings if they're using it above that "nominal" voltage.

It's a little tricky though, because everything is in SLA cell voltages.


Go to page 55.
This is for protection only:
- Nominal voltage: Set that to 36 * 3V = 108V
- Undervoltage cutback: Leave this alone.
- User overvoltage: Set to 115% for now (~124.2V)
- User undervoltage: Set to 80% for now (~86.4V)


Here's the important bit and likely where the issue is. This is what enables you to calculate SOC correctly. Curtis uses SLA cells, not lifepo4. See note at bottom of page 57. The number of cells in a pack is nominal voltage / 2. This for a 36 cell pack is 108/2 = 54. For a 32 cell pack, it's 96/2 = 48. 


- reset volts per cell: Take some voltage above full voltage (maybe 3.4V a cell) and multiply by 36. This would be something like 122.4V. Divide by 54. That's ~2.25V. Enter that into the "reset volts per cell".
- full volts per cell: Take the fully charged voltage (maybe 3.3V a cell) and multiply by 36. This would be something like 118.8V. Divide by 54. That's ~2.2V. Enter that into the "full volts per cell".
- empty volts per cell: Take the empty voltage (maybe 2.5V a cell) and multiply by 36. This would be something like 90V. Divide by 54. That's ~1.67. Enter that into the "empty volts per cell".


Keep everything else the same.


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## frodus (Apr 12, 2008)

to check throttle signal:
Go to page 64

go to monitor, go to inputs.

Vary the throttle (on a jackstand) and vary the throttle from 0 to full. Ensure that the value changes on "Throttle command" from 0-100% or somewhere "close".


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## licc (Aug 14, 2011)

Thank you. programmer shows BDI (SOC)= 87%. We have input new parameters for battery to the controller. Starting current previous - 70a ... 
At vary the throttle from 0 to full, the programmer shows "Throttle command" from 0-100%, it is ok. Possible bad motor settings (see a pic.)


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## major (Apr 4, 2008)

licc said:


> Possible bad motor settings (see a pic.)


You didn't change any motor parameters, did you? Did you buy it as a matched motor and controller set? From where?


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## licc (Aug 14, 2011)

We have not changed the parameters of the motor. Kit was purchased from 'KTA services'.


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## frodus (Apr 12, 2008)

let me see the first image of the menu. does it have "NEV" in the menu?

What is the max RPM that the motor will run?

How are you loading the motor?

Please answer all of these.


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## licc (Aug 14, 2011)

I have not found in the menu "NEV"
the max RPM is 6400
motor mounted on the car. wheels are raised off the floor.
If we omit the wheels on the floor, making full throttle, the current 70A and car slow speeds. With increasing speed of current is slowly increased.


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## frodus (Apr 12, 2008)

Well, the wheels off the ground is probably why!

Controllers do not PUSH current into the motor, they allow current to go to the motor. If you do not load the motor, you will not get current flow. The motor only gets what it requires. The controller doesn't force current into the motor. If the motor only needs 70A to get to 6400RPM, it's not going to get any more.


Put the wheels on the floor, put the parking brake on, and then see how many amps you pull. Drive the thing around!


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## licc (Aug 14, 2011)

wheels off the ground for measuring motor max PRM only. if wheels on the floor, and put the parking brake on we have 70a .


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## frodus (Apr 12, 2008)

Does it run smooth or rough?

What is under "user settings"?


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## licc (Aug 14, 2011)

motor is run smooth, in "user settings" sets the "torqe mode"


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## frodus (Apr 12, 2008)

Not sure then....

Did you run the motor characterization for some reason? If so, you weren't supposed to.

At this point, I'd get a hold of KTA, since they sold it to you.


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## licc (Aug 14, 2011)

I wrote a letter to the KTA, but no response...


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## frodus (Apr 12, 2008)

Can you do this (I know it's time consuming)

either write down, or take screenshots of every parameter and then email it to me.

Since you only have the handheld programmer, it's a little hard to look at everything remotely.


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## licc (Aug 14, 2011)

Ok. We have already night, tomorrow I'll do photos. Thanks for your help!


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## frodus (Apr 12, 2008)

email them, don't post.... easier to forward to someone if I can't figure it out.


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## Hippie Djohn (Oct 24, 2011)

licc said:


> I have not found in the menu "NEV"
> the max RPM is 6400
> motor mounted on the car. wheels are raised off the floor.
> If we omit the wheels on the floor, making full throttle, the current 70A and car slow speeds. With increasing speed of current is slowly increased.


If it is a standard OS, "motor type" should be 193 for the HPEV AC-50.
change motor type to 193.
If it doesn't help, HPEV have manipulated the motor type in the VCL code.


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## Hippie Djohn (Oct 24, 2011)

Hippie Djohn said:


> If it is a standard OS, "motor type" should be 193 for the HPEV AC-50.
> change motor type to 193.
> If it doesn't help, HPEV have manipulated the motor type in the VCL code.


BTW. 
When you set the motor type to: 193, SlipGain should also change to 0.85
and field weakning to 100%


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## licc (Aug 14, 2011)

Thank you, we will do it after the holidays. KTA answered to us, too.


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## tomofreno (Mar 3, 2009)

I know of one person who had a problem somewhat like this. They had an AC31 and acceleration was very sluggish. Turned out that the motor type entered by HPEVS was AC35 rather than AC31. After correcting the motor type it ran well. KTA could check with them and see if that might be the problem.


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## JRP3 (Mar 7, 2008)

I've wondered what the difference was between the AC31 and AC35, don't they have the same specs?


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## Hippie Djohn (Oct 24, 2011)

If you have the AC-50_2 you should select motor type 201, then slip gain will be 1.35 and field weakening still 100%.


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## licc (Aug 14, 2011)

We have the AC-50-1 motor.


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## Rational (Nov 26, 2011)

Making or finding a three phase source to test your motor by itself may not be easy, so the easiest most harmless test is to measure the resistances from each motor terminal to each motor terminal, and to the motor shell, 6 readings in all?and compare these readings to the motor maker's spec's.


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## frodus (Apr 12, 2008)

Shut. Up. Rational.


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## Rational (Nov 26, 2011)

frodus said:


> Shut. Up. Rational.


Looking through the manual that was posted, I see that the OP can use a DVM to read out what's on the 35 pin connector and so figure out what the controller is 'thinking'. The manual shows what you can expect to see on each pin.

Do you want to help the OP or do you want to preserve your own idea of what you are and what you know? Decide.


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## tomofreno (Mar 3, 2009)

JRP3 said:


> I've wondered what the difference was between the AC31 and AC35, don't they have the same specs?


 Don't know what they are, but evidently they are not the same since after HPEVS told them that was the problem and told them what to enter it worked fine.
Edit: Here is an excerpt from the email I received from the person who had the problem:
"Well, with Bill's help we finally found the problem: We had the wrong motor number. It should be 164. Our motor is marked "AC-35" (contrary to what I said below), but apparently is really and AC-31. According to Bill, these motors are quite different (different number of rotor bars, etc.), so this would explain the very poor and inefficient low-speed performance. He indicated that ours was mislabeled as the factory was in transition from AC-31 to AC-35."


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## major (Apr 4, 2008)

Rational said:


> Looking through the manual that was posted, I see that the OP can use a DVM to read out what's on the 35 pin connector and so figure out what the controller is 'thinking'. The manual shows what you can expect to see on each pin.


Hey Rational,

Have you ever tried to put a probe on a pin in that connector? And you don't need a DVM to "figure out what the controller is thinking". The handheld pendant will display all the inputs from the pins.

There are several members here who have experience with the Curtis 1238 trying to help licc. And then there is you. 

Sincerely,

major


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## Hippie Djohn (Oct 24, 2011)

Hippie Djohn said:


> If it is a standard OS, "motor type" should be 193 for the HPEV AC-50.
> change motor type to 193.
> If it doesn't help, HPEV have manipulated the motor type in the VCL code.


It is important to say that it's only with the standard operating system that I'm hundred percent sure this will work.
With the standard operating system you're able to see all the parameters in the manual

As I wrote, the VCL Code can make a big difference


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## Rational (Nov 26, 2011)

major said:


> Have you ever tried to put a probe on a pin in that connector? And you don't need a DVM to "figure out what the controller is thinking".
> 
> The handheld pendant will display all the inputs from the pins.
> 
> ...


You need a 'breakout box' or you need to be extremely careful.

Since there is a problem with this unit and if you have reason to disbelieve the pendant I'd probe the pins with a DVM known to be working properly. 
When something doesn't work, all bets are off. Otherwise you are presuming to know the cause of the problem without testing your assumption.

My experience is with many different electrical/electronic things in general, yours is specific. I think both can help. And, after all, the OP can always ignore my advice.
I've found that posting my resume/experience on forums does not help. Each member has to prove himself.

After I thoroughly read and understand every line of the manual that was posted I hope I will be able to give more specific help.

BTW, I have to give you and Frodus credit for not playing mind games. 
And, conversely, by now you have a pretty good idea of who and what I am.


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## major (Apr 4, 2008)

licc said:


> wheels off the ground for measuring motor max PRM only. if wheels on the floor, and put the parking brake on we have 70a .


You know? The parking brake gives you a locked rotor condition. So 70A might be logical for battery current. Phase current should be 500+.


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## cruisin (Jun 3, 2009)

Hippie Djohn said:


> If you have the AC-50_2 you should select motor type 201, then slip gain will be 1.35 and field weakening still 100%.


WARNING passed to me from HPEVS, changing the motor type in the programming can damage the motor and VOID the warranty. The AC-50 should have a motor type 50 in the programming. If one is not sure, call Bill at HPEVS and he will be happy to help.


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## licc (Aug 14, 2011)

Now we are on vacation. Will continue to work with mid-January.


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## Hippie Djohn (Oct 24, 2011)

cruisin said:


> WARNING passed to me from HPEVS, changing the motor type in the programming can damage the motor and VOID the warranty. The AC-50 should have a motor type 50 in the programming. If one is not sure, call Bill at HPEVS and he will be happy to help.


That's why I wrote that your controller should be equiped with the standard operating system.

But if LICC are seeing a slip gain of 1.35 for the AC-50-1 someting is wrong !
Wrong software or somebody had curious fingers, I don't know.
As mentioned, I have no experience with HPEV products or how they have chosen to configure the view-able part of the operating system , but I have 5 years of programming experience for Curtis AC-controllers.
My source says 0.85 slip gain for AC-50-1 and 1.35 for the AC-50-2.
So that could be an easy way to check if you have the correct SW for your AC-50 motor.
I wouldn't worry too much about destroying the controller or motor, they are very well protected, so if slip gain is within the 0.85-1.35 range I don't believe anything will happen, besides poor performance.
So check your parameters before testing
Anyway, it's always best to contact the person/ company who made the SW, if they are willing to support you. They *should * know best.


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## JRP3 (Mar 7, 2008)

Hippie,
Have you ever taken apart one of these controllers? I'm trying to get the cover off mine and I thought you were supposed to be able to unscrew the large brass bushings on each terminal but they are turning very hard, with some squealing, and don't seem to be coming off. I've only done about two full turns on one terminal, B-, and it's not getting any easier. I'm using Vice Grips to grab onto it.


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## Salty9 (Jul 13, 2009)

JRP3 said:


> Hippie,
> Have you ever taken apart one of these controllers? I'm trying to get the cover off mine and I thought you were supposed to be able to unscrew the large brass bushings on each terminal but they are turning very hard, with some squealing, and don't seem to be coming off. I've only done about two full turns on one terminal, B-, and it's not getting any easier. I'm using Vice Grips to grab onto it.


The data sheet http://curtisinstruments.com/index.cfm?fuseaction=cProducts.dspProductCategory&catID=8 seems to indicate 4 screws probably coming in from the back at each corner. The recesses may be filled with potting compound.


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## frodus (Apr 12, 2008)

Salty9, Can you reference an actual datasheet and page as opposed to a list of PDF's? Not sure what area you're talking about on the 1238.

The 1236-6301, 1238-6501 and 1238-7501 I own have no screw holes or places where it looks like there is potting compound. The heatsink is a solid block with no portrusions that I can see. 



JRP3, Pretty sure the cover is pressed on and sealed/glued in place. I don't think those connections are meant to unscrew.


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## Salty9 (Jul 13, 2009)

The data sheet link is at the end of the 1238-75 description paragraph. It is a download. 50175_1238R_Rev2......pdf.


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## frodus (Apr 12, 2008)

Where on the 50175_1238R_Rev*D*2.pdf are you seeing these screws? Maybe I'm missing something.



frodus said:


> Can you reference an actual datasheet *and page* as opposed to a list of PDF's? Not sure what area you're talking about on the 1238.


Could you be more detailed about what you're looking at (reference page, or at least a particular illustration)? I wouldn't mind taking apart my 6301.


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## JRP3 (Mar 7, 2008)

frodus said:


> JRP3, Pretty sure the cover is pressed on and sealed/glued in place. I don't think those connections are meant to unscrew.


I was just going by what a guy told me on the EVDL, and he provided pictures:
http://www.diyelectriccar.com/forums/showpost.php?p=268822&postcount=205
But they sure don't feel like they want to come off


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## JRP3 (Mar 7, 2008)

Salty9 said:


> The data sheet http://curtisinstruments.com/index.cfm?fuseaction=cProducts.dspProductCategory&catID=8 seems to indicate 4 screws probably coming in from the back at each corner. The recesses may be filled with potting compound.


I don't remember seeing any signs of screws or holes filled in with anything on the back of my 1238, just a solid chunk of aluminum, with the 4 mounting holes at the corners.


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## frodus (Apr 12, 2008)

Hmm.... looks like there might be some holes in the aluminum.... are they alignment pins or do they go through? 

My aluminum is one solid chunk with no holes....

will look at it in.... oh about 45 minutes..... I'll let you know what I find.


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## major (Apr 4, 2008)

frodus said:


> Hmm.... looks like there might be some holes in the aluminum.... are they alignment pins or do they go through?
> 
> My aluminum is one solid chunk with no holes....
> 
> will look at it in.... oh about 45 minutes..... I'll let you know what I find.


I remember one guy at a university who took an x-ray of it and put it on the web. I'm not sure if I can find that but it did show nicely what was inside


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## JRP3 (Mar 7, 2008)

If you click the link I provided you can see actual pictures of one opened up


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## Salty9 (Jul 13, 2009)

Sorry for posting. It seems I was "irrational".


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## frodus (Apr 12, 2008)

Salty9 said:


> Sorry for posting. It seems I was "irrational".


hold on a sec....

you, were actually right, I see what you meant. I have a heatsink on the one I use a lot and I didn't see them.... there are actually 4 screws on the bottom plate. I wasn't sure where you were referring to at first.....now I totally understand!

Thanks for the help!


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## frodus (Apr 12, 2008)

JRP3 said:


> Hippie,
> Have you ever taken apart one of these controllers? I'm trying to get the cover off mine and I thought you were supposed to be able to unscrew the large brass bushings on each terminal but they are turning very hard, with some squealing, and don't seem to be coming off. I've only done about two full turns on one terminal, B-, and it's not getting any easier. I'm using Vice Grips to grab onto it.


Same here, tried on my 1238 too, those screws come out easy, but those lugs do not. I think there's an o-ring that maybe seals it and the whole thing press fits on top, but it's still a PITA to try to pry up.

My 1236 came apart super easily and it was press-fit. Nice rubber seal along the edge and on all of the lugs.

I'm not TOUCHING my 1238-7501.


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## tomofreno (Mar 3, 2009)

JRP3 said:


> I was just going by what a guy told me on the EVDL, and he provided pictures:
> http://www.diyelectriccar.com/forums/showpost.php?p=268822&postcount=205
> But they sure don't feel like they want to come off


 The brass fittings in the photo look like the terminals for the 3 phases and the 2 DC terminals. I wouldn't twist them too hard or you might break them lose from the board.


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## JRP3 (Mar 7, 2008)

Yes that is what they are, but somehow that guy got them off. The brass ring does turn independently from the threads inside.


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## JRP3 (Mar 7, 2008)

I think maybe I didn't interpret the translation of the guy's instructions properly:

Ok, Donde se conectan los cables de alimentacion y motor, son unas arandelas de presion. 
debes levantarlas con una moldaza haciendo un pequeño giro de lado a lado

Ok, where you connect the power cables and motor, pressure washers are one.
moldaza you lift with a little twist of doing a side by side

So maybe I should be lifting up on the brass rings while wiggling back and forth?


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## tomofreno (Mar 3, 2009)

Could be they are just pressed onto a stud with an o-ring seal tight around the stud and onto the cover to seal it. Maybe some gentle twisting back and forth while lifting. Mind you, I would send it to Curtis, but I know you won't.



JRP3 said:


> I think maybe I didn't interpret the translation of the guy's instructions properly:
> 
> Ok, Donde se conectan los cables de alimentacion y motor, son unas arandelas de presion.
> debes levantarlas con una moldaza haciendo un pequeño giro de lado a lado
> ...


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## Hippie Djohn (Oct 24, 2011)

JRP3 said:


> Hippie,
> Have you ever taken apart one of these controllers? I'm trying to get the cover off mine and I thought you were supposed to be able to unscrew the large brass bushings on each terminal but they are turning very hard, with some squealing, and don't seem to be coming off. I've only done about two full turns on one terminal, B-, and it's not getting any easier. I'm using Vice Grips to grab onto it.


Sorry, no I didn't try to take one apart. Normally I throw defect controllers in the bin or send them to Curtis for warranty claims. 
Even though it is very rare to see warranty related faults on these units, normally it's human errors.


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## JRP3 (Mar 7, 2008)

tomofreno said:


> Could be they are just pressed onto a stud with an o-ring seal tight around the stud and onto the cover to seal it.


That's what I'm thinking. There is a small groove machined into each one that a small puller might grab onto. 


> Mind you, I would send it to Curtis, but I know you won't.


 Not until I *really* break it.


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## JRP3 (Mar 7, 2008)

Hippie Djohn said:


> Sorry, no I didn't try to take one apart. Normally I throw defect controllers in the bin or send them to Curtis for warranty claims.
> Even though it is very rare to see warranty related faults on these units, normally it's human errors.


Yes, complete human error on my part.  Now about those controllers you're tossing in the bin, they might be gold mine for people like me who need parts


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## Salty9 (Jul 13, 2009)

It might be useful while you have the controller apart to see how the MOSFETS (IGBTS?) are situated so that effective cooling can be arranged.


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## JRP3 (Mar 7, 2008)

Well I gave it a try, no go. I couldn't get a puller on it so I went back to Vice Grips, pulling from the top and trying to rock it back and forth. The car was rocking back and forth but the brass terminal did not budge. I stopped before I broke anything, I think . I'll probably contact the Curtis service center and see what they say: http://www.fsip.biz/Curtis.html


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## Salty9 (Jul 13, 2009)

Have you tried warming the terminals? I wouldn't use anything warmer than heat from a hair drier.


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## frodus (Apr 12, 2008)

JRP3, 

Wanna start a new thread, we took this way off topic....


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## Coulomb (Apr 22, 2009)

JRP3 said:


> Now about those controllers you're tossing in the bin, they might be gold mine for people like me who need parts


Or to cut open, to figure out how you could have opened it properly 

I often find after I've mangled something open, that it's then obvious how I could have and should have opened it.  With a junked controller that you are using just for parts, it's OK to mangle it open (unless the part you wanted was the case, of course).


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## JRP3 (Mar 7, 2008)

frodus said:


> JRP3,
> 
> Wanna start a new thread, we took this way off topic....


Why, it's about a 1238-7501 isn't it  Anyway, I'm done messing with it, whatever I end up doing I'll post in my build thread.


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## efan (Aug 27, 2009)

hey everyone, I was wondering if any of you know how the Sevcon Gen 4 (g8055) compares to Curtis 1238? has any of you worked with Sevcon?

http://www.electricmotorsport.com/store/pdf-downloads/sev_gen4.pdf


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## EV West (Jan 12, 2012)

Hi guys, 

Regarding cooling the 1238, we just finished our Curtis Chill Plate. Very affordable system for keeping the Curtis cool. 

We have complete information at the link below, and we even include an instructional video with your good friend Matt Hauber. 

http://www.evwest.com/catalog/product_info.php?cPath=25&products_id=104


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## frodus (Apr 12, 2008)

Nice! I might have to get me one of those!

(one other thing, if it fits the 7501 and 6501, it should fit the 7601 too)


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