# Main Contactor Coil Voltage for Curtis 1238 Controller



## major (Apr 4, 2008)

Caps18 said:


> Does the Curtis 1238 controller put out 48V DC to the coil side of the main contactor?........


It can. The coil driver is programmable. It is set to a percentage of the main input voltage. See page 48 of the manual.


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## frodus (Apr 12, 2008)

Where and when did you get your Curtis 1238? 

As Major said, its adjustable in the controller. Older HPEVS parameters had the coil set up for 24VDC. The newer ones they sell (for the past year at least) have the parameters set as 48VDC. 

The good news is you can adjust it with a programmer. 

I haven't seen any HPEVS setups come with MORE than 48V, so if you run the 48V contactor at 24V, it may not close, or it may close and not hold. If you got it fairly recently, and the contactor came as part of the kit, I'm pretty sure you'll be fine.


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## Caps18 (Jun 8, 2008)

Well, that information was pretty much hidden. And it is kind of important information to know. I was going to put my inertia switch and AVC2 charging disconnect on that wire. I'm not sure if those can handle 48 volts.

It would be nice if they said something about that on their auto1234-1236-1238_513-up_revb.pdf electrical schematic...

And I purchased this in March 2014, so it hasn't been too long.


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## dougingraham (Jul 26, 2011)

The coil current is fairly low so I would expect both of those devices can handle it. I estimate 200ma at 48 volts. Shouldn't be any wear on the contacts because there will be zero current except in the case of an accident where the inertia switch opens.


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## frodus (Apr 12, 2008)

All of the contactor stuff is in the Curtis manual.... Not the HPEVS manual. 

It also isn't a smooth 48v that electronics like. It's meant to drive just the coil, so don't put anything else on it. Connect per the schematic from HPEVS.


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## Caps18 (Jun 8, 2008)

I just realized that there was a possible error in my wiring diagram with the Coil Return (pin 13) blue/white. It goes to both the main contactor and the brake light relay. And if it has 48V on it when the main contactor is on, the brake light relay can only handle 32V DC. Do I need a new brake light relay? Or will it only see the voltage of the Brake Light Switch (pin 3)? Is it even allowed in the controller to have the regen and accelerator pressed at the same time and would that fry a lower powered device that was hooked up to the main contactor @48V and a max 32V Crydom relay?


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## frodus (Apr 12, 2008)

I can't see what pins go to what device, because you have them color coded.

Looks like the Brake uses pin 3, which is a 12V output. The Contactor driver is PWM'd from pack voltage, so lets just say its 48V. The coil return is negative, so imagine that both have a common negative, but pin 3 gets 12V, and pin13 gets 48V. 

Just follow this schematic and you should be fine:
http://hpevs.com/Site/images/jpeg/S...1236-1238/auto1234-1236-1238_513-up_revb .pdf


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## Caps18 (Jun 8, 2008)

It is pin 13, the coil return (blue/white) that was my concern. And it has been awhile since I've done electrical engineering on this scale, so I was worried when I realized that the page 2 overall schematic doesn't include anything from page 16. And that they didn't really mention that pin 6 is 48V and pin 3 is 12V, and both are connected to what I am assuming is a common ground.

(I will be asking about anything and everything that might be a problem as I am getting all these parts together and building this over the next few weekends. I don't want to have any mistakes.  )

Thanks for the help


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