# Curtis 1231C power



## F16bmathis (Jun 6, 2008)

While waiting for my Zilla to be fixed (my fault, Zilla's rule!), I installed my Curtis 1231C in the truck. Its a 500 amp controller, but I'm only getting 200 amps off the battery side, not sure of motor side. When I had previously had it installed, it put out a full 500 amps.

The Curtis manual shows "A2" connected to the "A2-S1" connection, but a wiring diagram I found on http://www.ev-power.com.au/-TECHNICAL-ARTICLES-.html says that the "A2" connection is for plug braking and not to connect it for a street vehicle! So when I wired this up, I didn't connect "A2". 

The Curtis manual only mentions plug braking in relation to the KSI connection.

I'd appreciate any help, but I'm going to go wire in the A2 to the A2-S1 connection and see if things improve.


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## F16bmathis (Jun 6, 2008)

Wired it up, now it runs in reverse! Not sure about power output. Back to wiring...


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## F16bmathis (Jun 6, 2008)

Hey look, the Curtis manual has a (fig 10) 4th? wiring diagram that is completely different from the rest. A2 to S2 motor connection instead of A2 to S1, M- to S1, and A2 to the A2-S2 motor connection.

Back to re-wiring...


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## F16bmathis (Jun 6, 2008)

Wired per Curtis Manual Fig 10. Runs forward, seems to put out the same battery amps (starts out really slow in 2nd gear, gets RPM's up to 6k or so, as amps reach 300+/-.


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## EVfun (Mar 14, 2010)

Please don't connect the plug braking system (A2.) Real EVs go to fast, that thing is only for forklifts. Using it in an on-road EV is mostly a way to blow up a Curtis.


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## F16bmathis (Jun 6, 2008)

I remember having it disconnected before when someone at our EV club told me I didn't need it, but I didn't remember which output (A2) it was. I've driven it almost 200 miles so far with it connected, but I'm just waiting for the 144V signal wire to break and send my controller into plug heaven. I'm at work now, but maybe I can sneak out and remove it...


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## F16bmathis (Jun 6, 2008)

Also, why doesn't the Curtis manual show this not connected. I had to go through three diagrams before I found the one that worked. If you follow the first two diagrams through the reverse relays, you'll find the wiring isn't the same as the third diagram.


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## major (Apr 4, 2008)

F16bmathis said:


> I remember having it disconnected before when someone at our EV club told me I didn't need it, but I didn't remember which output (A2) it was. I've driven it almost 200 miles so far with it connected, but I'm just waiting for the 144V signal wire to break and send my controller into plug heaven. I'm at work now, but maybe I can sneak out and remove it...


A2 on the controller is for plug reversing. You cannot plug reverse without a reversing contactor set. And since you say something about 2nd gear, I assume you use transmission for reverse and have the motor wired for unidirection. 

You can leave the A2 connection and this will help protect the controller in the case where you are rolling backwards and apply a forward throttle. It will give you an abrupt stop, so should be avoided. Other than that, the A2 connection does nothing in your set-up.

major


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## major (Apr 4, 2008)

F16bmathis said:


> Also, why doesn't the Curtis manual show this not connected. I had to go through three diagrams before I found the one that worked. If you follow the first two diagrams through the reverse relays, you'll find the wiring isn't the same as the third diagram.


O.K. F16b,

I give up. What's different, besides the field direction, which is dependent on your preferred rotation direction?

major


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## Woodsmith (Jun 5, 2008)

F16bmathis said:


> Also, why doesn't the Curtis manual show this not connected. I had to go through three diagrams before I found the one that worked. If you follow the first two diagrams through the reverse relays, you'll find the wiring isn't the same as the third diagram.


I found this with my Curtis 1214 on my Tractor. There wasn't any diagram without the A2 connection.

I tried with it disconnected and found the motor wasn't running as well, it felt like it was being strangled and was rough. With the A2 connected it would spin freely and produced lots or 'oomph'.
I figured I would leave it that way as it is unlikely the tractor will be going over 15mph or on the public road.


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## F16bmathis (Jun 6, 2008)

I disconnected it, all works fine!


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## major (Apr 4, 2008)

Woodsmith said:


> I tried with it disconnected and found the motor wasn't running as well, it felt like it was being strangled and was rough. With the A2 connected it would spin freely and produced lots or 'oomph'.


That's odd. Unless there was something going on with that axle causing an uneven velocity. If everything is "right" and running in one direction, it should make no difference whether A2 is connected or not. The plugging diode will be reverse biased and essentially disconnect A2


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## F16bmathis (Jun 6, 2008)

Fig 10 is the closest to what I have it connected as, but remove the A2 connection. A1 to B+
A2 to A2
A2 to S2
S1 to M-
So why show the A2 connected if we should not connect it? I read through a few times and maybe passed over where they said not to connect it for a street vehicle, but I didn't see it, so I'm sure I'm not the only one, or am I? I'm just saying...

In Fig 9 its the same but with reversing relay

In Fig 8,
A2 to S1, not A2-S2
S2 to M-, not A1, so they did this for.... I'm not going to spend the time trying to figure it out. Don't care to...

And Fig 7, I can't figure where the relay connections go inside the relay, but I can guess easily enough. Its just hard for someone who has not done this kind of work before to figure out.

Not that I need to know, mines working fine with A2 disconnected. I'll get a diagram I'm happy with and add it to the thousands of web pages with Curtis wiring diagrams! (add smiley face here)


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## F16bmathis (Jun 6, 2008)

Woodsmith said:


> I found this with my Curtis 1214 on my Tractor. There wasn't any diagram without the A2 connection.
> 
> I tried with it disconnected ...


Yeah, with my first truck, I had somehow (stupidity I'm sure) wired it wrong. Don't remember how, but at full throttle the truck would just barely run and got really hot for a 20 foot drive. I'd look over the diagrams again and maybe even highlight each wire as you triple check them. Try this... diagram at the bottom of this page.

http://www.ev-power.com.au/-TECHNICAL-ARTICLES-.html


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## major (Apr 4, 2008)

Hi F16b,



> so they did this for.... I'm not going to spend the time trying to figure it out. Don't care to...


I'm not sure why they did this. But it really does not matter for the S1 and S2 connections, except for the direction of motor rotation. Which I think you discovered. And Curtis does not know which way you want your motor to rotate. 



F16bmathis said:


> Fig 10 is
> A1 to B+
> A2 to A2
> A2 to S2
> ...


These connections, in the diagrams, are the same execpt for motor rotation direction  You have a typo, A1 always is shown to B+.



> So why show the A2 connected if we should not connect it?


If you have reversing contactors, you should connect A2, the plugging diode. If you don't have a reversing contactor and never command forward motor torque when rolling backwards, it does not make any difference. It just saves a few feet of cable and 2 lugs 

See Fig B-1 for a diagram of the plugging diode. 

major


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## Woodsmith (Jun 5, 2008)

major said:


> That's odd. Unless there was something going on with that axle causing an uneven velocity. If everything is "right" and running in one direction, it should make no difference whether A2 is connected or not. The plugging diode will be reverse biased and essentially disconnect A2


I was testing with the axle in neutral so it was only spinning the chain drive in either configuration. I was playing with having the A2 link switched so that it could control anti roll back and neutral braking when required but could be switched off when not needed.



F16bmathis said:


> Yeah, with my first truck, I had somehow (stupidity I'm sure) wired it wrong. Don't remember how, but at full throttle the truck would just barely run and got really hot for a 20 foot drive. I'd look over the diagrams again and maybe even highlight each wire as you triple check them. Try this... diagram at the bottom of this page.
> 
> http://www.ev-power.com.au/-TECHNICAL-ARTICLES-.html


Now that shows an immediate difference, though I am not sure what difference it makes.

In my manual B+ feeds the fields first (via reversing contactors), then the armature and returning to M-.
In your link B+ feeds the armature first, then the fields and back to M-.

Not sure that should make a difference but maybe it does.


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## F16bmathis (Jun 6, 2008)

I'm using the tranny to reverse, well, to do everything. I use all gears when I want to go fast, and 2nd and up when normally driving.

When mine was acting up / going really slow / no power, I really had wired it in wrong. Not sure how it was wired (it was a few years ago) but after I re-wired it (still using the A2) it ran so much better. Eventually I pulled off the A2 like I did today. No difference driving it.


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## Ziggythewiz (May 16, 2010)

Came across this while looking to see what the plug braking adjustment screw was for...pulled my A2 lst night. Still runs great 

It's really helpful that curtis and others provide 3-4 ways (all with A2!) to wire things up with no indication that following the directions could be dangerous for an on road application...


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## dtbaker (Jan 5, 2008)

I believe the 'standard' for EV is:

motor A1-> contactor + -> batt +
motor A2-> motor S2
motor S1 -> controller M-

controller B- -> batt -
controller B+ -> contactor + -> batt +


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