# Curtis 1221 R



## faradohm (Oct 5, 2010)

Hello,

i'm rebuilding a 1221R curtis controller.

I'm looking for the datasheet of SR4180R 1 diode / motorola....

it's a two plate monuting similar "to220" with rounded diode insered in....

thank's


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## Tesseract (Sep 27, 2008)

Take a picture of the part because I can't find it, nor does it seem like a valid Motorola part number (Curtis likes to use Motorola dual-diodes with a common anode).

An example of a valid part number would be MUR1620CTR - the CTR suffix is important is it indicates the rectifier is a Center-Tapped, Reverse configuration.


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## faradohm (Oct 5, 2010)

hello , I've found the name of the case,

its "to-220 button"

see view one:

http://61.222.192.61/mccsemi/up_pdf/MR2400FR-MR2410FR(TO-220).pdf

your "MUR1620CTR" is a dual diode....not good for me!

mine is single, anode on pin 1 (left view front)....

no data-sheet found at this time

I think it is about 200V / 40A , but its imposssible in to220 normal case!

bye


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## Tesseract (Sep 27, 2008)

faradohm said:


> I think it is about 200V / 40A , but its imposssible in to220 normal case!


Sorry - can't help you. Your original part number is not a valid one for rectifiers; it cross-references to a crystal oscillator.

You will need to be able to determine what the diode is doing in the circuit - is this one of the freewheeling diodes, for example? - and then pick a substitute based on the controller's ratings.

Also, it is quite possible to have a 200V/20A rectifier in a TO-220 package as long as the Vf is less than 1.2V or so and the total thermal resistance from junction to heatsink is less than 3C/W.


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## faradohm (Oct 5, 2010)

yes it's for free-wheel. and regenerate too.

with 300A of current in max braking ,there are 12 diodes (and no place for more), it need 25A minimum...each


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## Weisheimer (May 11, 2009)

faradohm said:


> yes it's for free-wheel. and regenerate too.
> 
> with 300A of current in max braking ,there are 12 diodes (and no place for more), it need 25A minimum...each


 
I've used the MUR2020R in 1221's (and other early Curti) and they will work, despite a lower 20 amp current rating.
I honestly am not recommending them, but there is simply no other alternative that I am aware of.
These are still available, but probably won't be for long as they are the reverse polarity of their FAR more common cousins.

http://www.onsemi.com/PowerSolutions/product.do?id=MUR2020R

Cheers

Mark


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## jehan12413 (Feb 4, 2010)

I also have used the MUR2020R sucessfully. I am also working on an idea where I will use TO242 diodes which are not reverse and mount them sideways above the original TO220 location. Then I can use short jumpers from the appropriate leads the board. The only drawback is that they must be insulated from the heatsink. Just an idea.


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## faradohm (Oct 5, 2010)

Hi for all...

recently , one of sr4180r diod flashed on road...
diod replaced but curtis desn't works any more...
there was a flash on board next to...
i found a wire conductive on board cutted , an ic lm358out of arder too...
It works on table now , except the "drive" solenoid command who turn off after throttle..!
It's too , i'm powerless in front of this problem without schematic of this card.
It's the card with molex connect and 4 opto's on....
if neither some body as ever work on, i'm interested;

and excuses my poor writing english level!

thank's


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## faradohm (Oct 5, 2010)

For update....

I found faultly capas 0.1µF everywhere!

after all replace at new , it's ok


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## faradohm (Oct 5, 2010)

faradohm said:


> For update....
> 
> I found faultly capas 0.1µF everywhere!
> 
> after all replace at new , it's ok


so, re-comming there for new bad adventure
friend's curtis has decided to burn out at power on moment.
Worked well day before....
Not glad at all to repair again these 1231r models....
no more good news with a full schematic there....?....


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## faradohm (Oct 5, 2010)

or if someone can give a mink or , experience with....

our need is a serial motor controller , in sep-ex wiring
eventualy with the marvoulous recuperation mode on brake foot....
as the original 1221R from curtis....

we think the recently change of battery techno,
pb or ni-cd , to lithium, with less of intern-resistivity,
even with same nominal voltage, 96v,
can cause dammage to these controllers,
cause the more important power to dissipate ,
(Vin-Vout)xI...
so , new model , or repair original , will see the max direct current,
max reverse current,and max brake current, 2 half reduced ....
🙃


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## kangoofarad (7 mo ago)

good news , curtis saved , tested and re-bult on car!
the fault was cumulated dusty inside , dammage on isolattion pad , between bus and pcb.
A dead npn transistor mps750 of low branch push-pull driver stage,
and photo-flashed rc components....
Current value revised to low (1/2 approx) by A limit pot ....

to follow...i hope no


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