While browsing the forum, I ran across a posting by Lionelsoni in 2007 that described a simple DC conversion that involved substituting a bridge rectifier for the e-unit.
I was unable to clearly understand the process, so this post is a request to Lionelsoni to make a sketch of that schematic so the less experienced (mostly me, I’m sure) can do the deed for themselves.
Also, it was unclear to me whether the converted engine is intended to operate on AC or DC track voltage, so I like to get that cleared up,as well.
I just checked to see that I am closing in on 10,000 posts, and I just don't remember that thread or what problem I was trying to solve in that one. Can you give me a link to it? Or just post a new reply to it to bump it to the top.
Bob Nelson
lionelsoniI just checked to see that I am closing in on 10,000 posts...
Converting a DC locomotive in AC
Rob
The conversion to DC is quite simple. Connect the AC terminals of a bridge rectifier in series with the power feed to the univesal motor field winding. Individually connect each of the motor brushes to the DC terminals of the rectifier. The universal motor will now react directionally to DC polarity just like a can motor.
Thanks for stepping in, Bob. I've been distracted by some difficult repairs on my 1966 daily-driver Volvo.
I hope the original poster can confirm that that's the conversion he was looking for, that is, that the converted locomotive's direction would be controlled by the polarity of the DC track voltage, as if it had a permanent-magnet motor.
To be able to reverse direction of the locomotive, you will need to switch the DC polarity of the bridge rectifier outputs using a Double Pole, Double Throw (DPDT) switch.
The motor will run on AC track voltage.
Larry
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