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Want to build CDU from kit or diagram/parts list.

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Want to build CDU from kit or diagram/parts list.
Posted by riogrande5761 on Thursday, February 12, 2015 6:36 AM

I want to build a Capacitive Discharge Unit to drive my Peco twin coil switch machines. I don't seem to be able to throw my Peco turnouts with a simple momentary contact button and A/C power alone.

Can anyone point toward any kit CDU's or parts list and diagram that will allow me to build one for a cost savings over the already made ones.  I'm on a budget.

Thanks

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by woodone on Thursday, February 12, 2015 7:12 AM

Take a look here. Sould help you out.

http://home.cogeco.ca/~rpaisley4/CDPSU.html

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Posted by rrinker on Thursday, February 12, 2015 7:25 AM

 Scroll down to the heading "Current Blocking Switch Machine Power Supply". The top one in the white block in that section is what you want. Fast recharge, simple circuit. I built essentially the same thing from the Kalmbach book "Practical Electronic Circuits for Model Railroaders" by Peter Thorne many many years ago. The second circuit in that block just adds an LED that lights when the cap is charged - not necessary, but for a $1 more in parts maybe it would be a fun addition, more blinky lights impresses some people.

             --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richg1998 on Thursday, February 12, 2015 8:32 AM

Circuitron sells the Snapper that operates off of AC as well as DC.

I built the below some years ago to fire a Peco three way.

http://www.awrr.com/cdsupply.html

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by richg1998 on Thursday, February 12, 2015 8:39 AM

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by riogrande5761 on Thursday, February 12, 2015 9:07 AM

Lots of good suggestions and resources.  BTW, I seem to remember someone posting a link to a vendor who offered kits as well, for a fairly modest price?

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Thursday, February 12, 2015 9:16 AM

I just did a Google search for capacitive discharge unit kit

One result below.

http://www.talkingelectronics.com/projects/CDU-2/CDU-2.html

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by richg1998 on Thursday, February 12, 2015 9:31 AM

Do a Google search and then click on Images, you will get loads of circuits.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by rrinker on Thursday, February 12, 2015 10:30 AM

richg1998

I just did a Google search for capacitive discharge unit kit

One result below.

http://www.talkingelectronics.com/projects/CDU-2/CDU-2.html

Rich

 

 Of theirs, I'd go with the MkIIB - the top one only has 2000uF total, which is on the low side, the MkIIB has 4400uF for significantly more storage - mainly important if you have situations like crossovers where more than one switch motor fires at the same time.

           --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Thursday, February 12, 2015 12:16 PM

The one i did to fire the peco three way, I increased c2 to 10,000 ufd.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    June 2007
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Posted by riogrande5761 on Thursday, February 12, 2015 5:06 PM

Rich/Randy, thanks.  Today all my brain power went to trouble shooting some IT issues so I needed to be fed with a spoon!  The kit looks good!

Rio Grande.  The Action Road  - Focus 1977-1983

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