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Bachmann pancake motor smoking and sparking!!!

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  • Member since
    July 2020
  • 42 posts
Bachmann pancake motor smoking and sparking!!!
Posted by Traincraft199 on Saturday, March 20, 2021 10:07 AM

I was running my bachmann 4-8-4 northern and I saw smoke coming out of it. I opened it up and ran it and there were bright sparks popping inside the motor! This seems very alarming and I don't know what to do. Should I try to fix it or find a replacement motor?

I recorded a video of it:

https://www.youtube.com/watch?v=1s-Ij-0X2Uk

[Edit: Link made clickable by moderator]

Building my first layout, 4x8 contemporary urban area in HO scale 

  • Member since
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  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Saturday, March 20, 2021 10:41 AM

I had a half dozen Bachmann Pancake Motor 4-8-4s and the wheels fell off before they had enough running time to ding the motor.
 

Mel



 
My Model Railroad   
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I'm beginning to realize that aging is not for wimps.

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Posted by mbinsewi on Saturday, March 20, 2021 11:21 AM

It's the brushes.  Take it apart and clean the armature.  There are lots of YouTubes out there that will show you how.

Google Bachmann pancake motor.

Mike.

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Posted by Traincraft199 on Saturday, March 20, 2021 12:09 PM

the brushes just disintegrated when I tried to clean them...

Building my first layout, 4x8 contemporary urban area in HO scale 

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Posted by PM Railfan on Saturday, March 20, 2021 1:08 PM

I checked out your video. While you have the shell off, now is a good time to replace any broken, or slipping axle shafts too. This is another of Bachmanns 'common' problems.

Unfortunately this design flaw has carried over to other manfacturers of 'multi piece' axles. Such as the 'Proto' series. However, there are parts available for some of these. For Bachmann..... good luck.

I had to make my own Bachmann replacements. Be leary of models with multi piece axles, Ive never had to replace a solid axle in 50 years. (Manufacturers take note!)

 

PMR

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Posted by doctorwayne on Saturday, March 20, 2021 1:20 PM

The pancake is obviously over-cooked...shoulda used more syrup.

Wayne

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  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Saturday, March 20, 2021 1:23 PM

It’s been over 20 years since I was into a Bachmann pancake locomotive and I can’t remember what the brushes look like.  Can you post a picture of the brushes?
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Saturday, March 20, 2021 1:32 PM

I found a picture online with a Google search, I think the brushes are 2mm diameter if so try some 2mm mechanical pencil filler lead.  Cut it to about 4mm long and reassemble the motor and see if it runs.
 



Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

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  • From: Western, MA
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Posted by richg1998 on Saturday, March 20, 2021 1:35 PM

If you get the motor running and ever need axles Shapeways.com makes them from what I have heard. You might find a motor on ebay. Last I heard they make them for the 4-8-4.

 

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
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  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Saturday, March 20, 2021 1:43 PM

I think the Shapeways Bachmann gear is for the Plus Series and I tried some, they didn’t last very long.  They crumbled into pieces fairly quickly.
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    January 2013
  • 1,034 posts
Posted by PM Railfan on Saturday, March 20, 2021 2:46 PM

Yeah, add more syrup! Laugh

 

I couldnt find any replacements for my 2-8-0. So i 3d printed my own in ABS. While durable enough, they eventually started to slip. Allowing the rods to do their own thing, thus allowing the drivers to bind, blah blah blah.

Its just a bad design that can only be fixed by replacing with solid axles. I did however discover that Bachmanns run real good as shelf displays.

The OP, if so inclined, could always take the shell and replace the drive with another motor/frame from another manufacturer.

 

PMR

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Posted by Overmod on Sunday, March 21, 2021 7:45 PM

The motor can be fixed by replacing the brushes, truing and cleaning the commutator (cleaning out between the segments) and making sure the spring contacts are clean and make good contact with the back ends of the brushes.  

The bad news, though, is that the motor likely got in this condition by being massively overloaded -- by resistance, or wear, or slop in the drivetrain.  So much current was required that the brushes were sparking and overheating.  They are carbon, so they burned, cracked and crumbled -- something observable with old overloaded diesel-electric switcher traction-motor brushes, too! -- and the resulting sparking probably significantly eroded the commutator faces.  That will happen all over again when the 'rebuilt' motor is put back to be overloaded again.

It may be difficult to rework the chassis to run freely and well, but that, more than just rebuilding the motor, is essential.

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Posted by Traincraft199 on Saturday, March 27, 2021 1:36 PM

It seems to be fixed now. I thoroughly cleaned the motor as best I could with 99% isopropyl, and I stole and cleaned better brushes from an old bachmann diesel. no more sparks or smoke but time will tell

Building my first layout, 4x8 contemporary urban area in HO scale 

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