# Curtis 1238-7501



## Nick Smith (Oct 26, 2007)

Does anyone have any "real world" experience with this controller, specifically with how to wire it? I am quite familiar with the Curtis DC controller and probably because of this I am having trouble with understanding how to wire up AC system KSi input without putting full pack voltage into my cars 12v system.

The DC contoller system shows a KSi relay powered by the 12v (control) system which switches pack voltage to the controller. The AC system wiring diagram does not show this "but" the wiring is shown in the thin linetype (thick lines for pack voltage) that would seem to indicate "control" wiring voltage i.e. 12v.

Am I letting the DC controller wiring diagram lead me astray? Should the AC controller KSI input only be 12v? This would seem to make more sense to me. No mention either about whether to fuse this line or not.

On the other hand! The manual indicates that the precharge is now taken care of internally and hence the KSi would need to provide the pack voltage to charge the capacitors.

If this is the case, does the controller provide isolated power outputs to drive the main contactors etc. and what voltage is this? As you can tell, I am finding the Curtis manual less than clear on these issues. 

Any feedback/thoughts would be appreciated. Hopefully Jack Rickard will cover this in detail on EVTV.me


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## tomofreno (Mar 3, 2009)

You should have gotten a small 12V automotive type relay supplied by HPEVS that connects to pin1 (blue wire, "controller enable") on the controller, and through a 10A fuse to the positive terminal of the contactor. This supplies pack voltage to the controller, and acts as the "pot box relay" as described by Mike Brown in Convert It. You also should have received a wiring schematic from HPEVS which shows this. The coil of the contactor connects to pins 6 (orange/white) and 13 (blue/white) on the controller. Precharge is internal.


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## Nick Smith (Oct 26, 2007)

Thanks for the info. I must "come clean" and admit that I don't actually have a controller - yet. I have recently bought a donor vehicle and was reworking the circuit diagrams in preparation for an AC drive system.

I have been on the HPEV website but it is early days in the webpage development & you only find the same old pictures of motors and controllers as everywhere else. If you know of someone who has the schematic I would very much like to get hold of a copy though. My "local" curtis agent (all the way over in Sydney, Australia) hadn't even heard of the 1238-75 controller - so the call went out.

From what you say it would seem that the KSi turns on with the key and stays on to provide precharge to the controller, which is what I would have expected. I will maybe ask HPEV for a copy of their wiring diagram and study it carefully.


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## Nick Smith (Oct 26, 2007)

I have been busy trawling the net and found out some more stuff.

Seems that the contactor output is PWM dc and can be set in the software to run 12v, 24v coils anywhere up to the pack voltage. I have noticed that a lot of the resellers are suggesting that a contactor with a 24v is necessary but it looks like I could use my Albright SW200 12v.

I have also found a wiring diagram which I have attached. It answers nearly all my questions - now to find some time to actually sit down and read the curtis manual!


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