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pullmor motor for dc operation.

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  • Member since
    April 2003
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pullmor motor for dc operation.
Posted by Anonymous on Saturday, April 15, 2006 2:22 PM
I know this has been asked befor, but I cant seem to find what I want.
Is there a way to wire a pullmor motor for dc operation, but still suply ac
voltage to the tracks. I want to use my current transformers, and have
forward and backward operation, and still be able to use the air whistle.
Am I dreaming here, or can this be done?
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Saturday, April 15, 2006 3:11 PM
"Is there a way to wire a pullmor motor for dc operation, but still suply ac
voltage to the tracks."

You could wire in a bridge rectifier between the power leads to the motor and the motor itself.

"I want to use my current transformers,"

No problem, so far.

"and still be able to use the air whistle."

You will have to completely isolate the relay and air whistle components. A lot of PW trains used comon wires to feed current or collect return feeds to the wheels (saved wire and labor costs).

"and have forward and backward operation"

This is the tricky part. As you are rectifying the AC current to DC with a bridge rectifier, you need to figure a way for the E-Unit to swap the polarity of the current going to the motor(s).

My biggest concern is why would you do this? It involves a lot of rewiring and what do you hope to gain?
  • Member since
    April 2003
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Posted by Anonymous on Sunday, April 16, 2006 11:08 AM
Space allowing,you can mount a 6amp bridge rectifier inside a postwar loco and add a polarized capacitor. On steam such as a 2055 ect you have to break a grounding tab from the frame to the motor. On some Lionel engines it is impracticle to seperate the frame ground from the motor. The pullmore will run on AC or DC it does not care. However on DC with a capacitor it will run much smoother on the low end similar to a can motor. If you do a conversion make sure everything is insulated.

Dale Hz
  • Member since
    December 2001
  • From: Austin, TX
  • 10,096 posts
Posted by lionelsoni on Sunday, April 16, 2006 12:29 PM
Put the rectifier upstream of the e-unit, which will then reverse the motor whether it is running on AC or DC.

Bob Nelson

  • Member since
    December 2005
  • From: Hopewell, NY
  • 3,230 posts
Posted by ADCX Rob on Sunday, April 16, 2006 1:57 PM
Bob has the easy solution again - here's a little more detail...

use a 6-10 amp bridge rectifier before the e-unit: send all center pickup current for the motor out along the "+" output leg of the rectifier, disconnect the motor field connection to ground and attach that to the "-" leg of the rectifier. The "~" legs go to center rail & ground, either way - it doesn't matter.

Depending on the connections at the e-unit, you may have to seperate the wires at the fiber terminal block / e-unit switch to isolate DC for the motor, AC for the e-unit, or isolate the e-unit coil from ground also and connect to the rectifier to run it on DC too.

It's all easily reversible later if desired.

Rob

Rob

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