Can I use a 24 volt oil burner transformer to repair USA 40M

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  • Member since
    July, 2018
  • 2 posts
Can I use a 24 volt oil burner transformer to repair USA 40M
Posted by pethia on Friday, July 27, 2018 9:01 AM

I run G scale and have a USA trains 40M transformer that has a bad original transformer.  There are no markings on the transformer itself.  Charles RO says it is not repairable.  I was wondering if I could replace the power transformer with a 24 volt oil burner transformer?

  • Member since
    August, 2005
  • From: North Coastal San Diego
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Posted by Greg Elmassian on Friday, July 27, 2018 9:34 PM

hard to tell what the original voltage of the transformer was... is your replacement candidate 10 amps?

 

Greg

Visit my site: http://www.elmassian.com - lots of tips on locos, rolling stock and more.

 Click here for Greg's web site

 

  • Member since
    July, 2018
  • 2 posts
Posted by pethia on Saturday, July 28, 2018 6:48 AM

The replacement transformer is rated 40 volt amps at 24 volts. 

thanks for your input!

  • Member since
    December, 2008
  • From: Florida, USA
  • 100 posts
Posted by Narrowgauge on Saturday, July 28, 2018 7:28 PM

I know enough about electronics to be dangerous, so take it as forewarned.

 

First I would be looking to see what the output voltage of the 40M was supposed to be. If the output voltage is supposed to be above 21 or so volts the 24 volt input transformer may not be high enough voltage to cover the drop of converting from AC to DC plus filtering, etc. And that assumes that the other circuitry is sized for that voltage.

 

If the output voltage is only rated at 18 volts DC, a 24 volt input may be too high for the older electronics to handle, therefore when you turn it on you may let the 'magic smoke' escape.

 

My personal recommendation would be to replace it with an modern unit like a Bridge Works (NO CONNECTION WITH just good product). If you feel lucky, try to replace the transformer and see what happens. Either way, good luck.

 

Bob C.

  • Member since
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  • From: North Coastal San Diego
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Posted by Greg Elmassian on Friday, August 03, 2018 8:46 PM

So the power pack is offered as 24v dc, so an AC transformer will put out 1.4 times that voltage when rectified to DC, so you want about a 17 volt AC transformer, although with a full wave bridge, you lose 1.4 volts so you want about an 18v AC transformer.

So the answer is 24 volts AC is too high.. find an 18v one and that runs 18v under load.

 

Greg

Visit my site: http://www.elmassian.com - lots of tips on locos, rolling stock and more.

 Click here for Greg's web site

 

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