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Author Topic: Smoked my 0-4-0 Gas Mechanical  (Read 3350 times)
Broken Shay

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« on: August 25, 2011, 03:38:30 AM »

Had a  Gas Mech that had other issues and the thought of a battery powered critter came to mind and playing around with a 9v battery and just the motor from the GM I hooked it up and all was good for about 15 seconds then ...............smoke..............

Now I am really confused, I have another one that has a Bachmann decoder hooked straight up to the motor without going through the original board.  The decoder puts out 12-14v for the motor and yet the 9v fried the other motor.

Bach-Man    I need some clarification.  Is the smaller motor in the GM not able to handle the 9v?  If not why is the same motor working off a decoder without the benefit of the original circuit board?

Thanks for any help

John
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NarrowMinded


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« Reply #1 on: August 25, 2011, 09:24:48 PM »

Did the motor seem to run over normal rpm's they will sqeal usually if they are redlined.

they should take more the 9vdc given the fact you can swap any decoder into them and change the voltage, mine has a TCI decoder and runs fine.

NM-Jeff
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Broken Shay

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« Reply #2 on: August 26, 2011, 02:33:02 AM »

not over reved at all,  smoke seamed to be coming from the brushes.

John
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NarrowMinded


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« Reply #3 on: August 26, 2011, 10:24:52 PM »

Thats strange smoking brushes would point more to over amped brushes I would think, but with no load on it that seems unlikely.

Maybe Jim Banner will chime in on this.

JIMMMMMMM?


NM-Jeff
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Broken Shay

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« Reply #4 on: August 27, 2011, 06:16:51 PM »

Well,

Decided that messing with these small motors with a 9v is not a good idea.  they work fine behind a decoder.  Tried a mogul motor  with the 9v and it was fine.  I can make the mogul motor work for what I want to do so that is the route I will head.

Everyone I explain this too cannot understand why it smoked really 3 motors smoked.  Going to stick with what works

thanks

John
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Jim Banner

Enjoying electric model railroading since 1950.


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« Reply #5 on: August 29, 2011, 12:27:12 AM »


Everyone I explain this too cannot understand why it smoked really 3 motors smoked. 


Sorry John, but I am missing something here.  Did you smoke 2 other motors beside the one in the gas mechanical?  Were they all gas mechanical motors? 

When I thought it was just one motor that smoked and it was from a locomotive with issues, I thought of a Bachmann H0 locomotive with issues that was brought to me with the request that I check out the decoder.  Sometimes it would run in reverse.  Sometimes not.  Sometimes it would run normal speeds going forward.  Sometimes it would barely run at all.  It turned out that there was a plastic arm from an engineer figure caught inside the motor.  As both the engineer and the fireman both had both their arms, I have no idea how it got there.  Sometimes it worked like a pawl and ratchet in reverse, stopping the motor from turning.  Sometimes not.  Sometimes it dragged against the armature, slowing the motor down in forward.  Sometimes not.  I tried various ways of dislodging the arm, including powering up the motor, which let the smoke out and finally settled the question of whether or not the locomotive needed a new motor.

The point of my story is that is had me wondering if there was a fault in your motor that not only let the smoke out but was also causing the issues with the locomotive in the first place.  But three faulty motors?  The odds are very much against it.  That now has me wondering if NarrowMinded isn't closer to the truth.  These little motors do have limits to the rpm's they can turn before damaging themselves.  If the bushings are well lubricated and in good shape and the motors have no load, they can turn their armatures fast enough that centrifugal force will expand the windings right out of their slots and peel the commutator bars loose from their attachments.  Expanded windings can short, usually to the iron core of the armature, causing the motor current to increase dramatically.  If the current to the motor is limited, the motor will slow.  If not, arcing will occur until something (windings, brushes, wiring to the motor) fails.  A fresh 9 volt alkaline battery can easily produce 10 or more amps and as far as the motor is concerned, is an unlimited source of power.  If the commutator bars start to move outwards, they will bounce the brushes in and out of contact which will tend to limit the motor speed just as a governor would but at the expense of the brushes burning away from the heavy arcing.  In this case too the motor will fail but from the brushes and commutator being burned away.  And sometimes a motor will develop a short, usually in the windings but occasionally between the commutator bars, under normal operating conditions.  I think they do this just to be ornery.  And sometimes we kill the motors, not for being ornery, but because they have a limited useful life and we exceed it.  The usual mode of failure here is that the brushes wear down to nothing and then the arms that typically support the brushes in a can motor wear away, and then it stops.

Now I don't know for sure what happened to you motor(s).  The above are just some possibilities I have run into over the years.  Fortunately, these little motors are not overly expensive to replace.  They are also repairable but I would not recommend that unless the motors are really irreplaceable and you are feeling very rich.

Jim
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Growing older is mandatory but growing up is optional.
railtwister

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« Reply #6 on: August 30, 2011, 10:02:40 AM »

Oil on the brushes canl cause smoke. It can also short out the commutator by causing carbon powder (from brush wear) to stick in the slots between the commutator plates. This can be flushed with a solvent like Ronsonol or Zippo Lighter fluid (Naptha), and the slots can be gently cleared with the pointed end of a toothpick. Be sure to allow the solvent enough time to fully evaporate before applying power, to avoid any chance of it bursting into flames.

Bill in FL
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Broken Shay

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« Reply #7 on: August 30, 2011, 12:47:33 PM »

Jim, 

In total there where 3,  it looks like with a straight 9v battery hooked to the motor it will smoke the smaller motors all day long.  I did the same test to a Mogul motor and it was able to handle the inrush of current fine.  The one that I took apart had the brushes melted into the plastic housing.

Lesson learned..........  put a decoder or other speed control in between the motor and power source.

One of the motors that smoked came from a working locomotive that had the stock Bachmann board (not decoder) in place.

They where all the same motor, the small can motor.

John
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wsboyette

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« Reply #8 on: September 04, 2011, 04:42:12 PM »

Get a Lionel, and you will not have to work on it or worry about motors burning up....  Grin
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NarrowMinded


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« Reply #9 on: September 06, 2011, 10:38:40 AM »

Wsboyett,

Does lionel make on30 gas mech loco's? also he didnt burn them up running them on the track, he burned up the motors which he removed from the loco and applied power to them. Atleast thats how i read it...

I have a little davenport that pulls 9 wood ore cars it has hundreds of hours on it and runs like a champ

Jeff
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Broken Shay

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« Reply #10 on: September 07, 2011, 11:48:16 PM »

Bet I could burn up a Lionel motor too,

This had NOTHING to do with Bachmann,  I burned them up playing with an idea.

John

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DWU

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« Reply #11 on: September 23, 2011, 09:20:57 AM »

Broken Shay,Join the crowd I learn everything the HARD WAY! I smoked my lawn mower 3 weeks ago,Bachman didnt make it!
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