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Marx #333 running HOT!

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  • Member since
    December 2001
  • From: Austin, TX
  • 10,096 posts
Posted by lionelsoni on Wednesday, December 15, 2010 9:16 AM

I don't have an example of the locomotive nor any documentation for it; so I can't evaluate your description of the wiring.  But that starting behavior, as well as the overheated field winding, is certainly consistent with parallel wiring.  A motor with the field in parallel with the armature tends to want to run at a particular constant speed, regardless of voltage.  As you increase the voltage from zero, the field and armature currents rise until there is enough torque to start the motor.  With a little more voltage, it quickly jumps up close to that speed that it prefers, the "kick in", as you aptly called it.

Bob Nelson

  • Member since
    January 2008
  • 31 posts
Posted by NYCentralFan on Wednesday, December 15, 2010 7:22 AM

Thanks!  I took it apart, again, and it seems that the left motor brush goes up and ver down into the frame and is solder to the rear tab of the reversing unit.

The top wire from the stator (I had them backwards in the last posting, no fixed), that you call the "field" goes down the sme path, but I cannot see where that is soldered.  The bottom stator / field wire goes down the left side of the frame, but again, I cannot see where its soldered.

From the pictures I can find online, this is the factory arrangement.

It makes a fairly loud hum when first starting, then seems to "kick in".

  • Member since
    December 2001
  • From: Austin, TX
  • 10,096 posts
Posted by lionelsoni on Tuesday, December 14, 2010 9:09 PM

Check to see whether the armature and field are properly wired in series, rather than incorrectly in parallel.

Bob Nelson

  • Member since
    January 2008
  • 31 posts
Marx #333 running HOT!
Posted by NYCentralFan on Tuesday, December 14, 2010 8:31 PM

I started a new post on this, because my #333 seems to flinging molten solder while running...

It seems that my 333 likes to run hot, and I mean HOT!  It ran so hot on Monday, that it melted the solder that holds the copper wire from the winding on the ROTOR and soldered to the ROTOR frame.  Luckily, I had some higher-temp Pb-free solder and was able to touch it up, but should it run this hot?

How do I get it to run cooler?  It's WELL lubed and the wheels roll very freely when the ROTOR is out.

Thanks, Mario...

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