Ho engines triggering overload light gradually. Help

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Trainman2716

New Member
When running some of my ho engines they will have this issue we’re they will run for a minute slow down to a stop and trigger the overload light
Here’s a video detailing the problem
 

D. Soppy

Member
If it only happens to some of your engines , there could be a problem with the motor shorting out due to excessive carbon buildup on the armature. This usually happens in older engines and the commutator can be cleaned with brake clean or similar degreasing solvent. If it happens to all your engines , then I would suspect the controller. The only sure way is to insert an amp meter in series with one of the controller lines and measure the current.
 

Trainman2716

New Member
If it only happens to some of your engines , there could be a problem with the motor shorting out due to excessive carbon buildup on the armature. This usually happens in older engines and the commutator can be cleaned with brake clean or similar degreasing solvent. If it happens to all your engines , then I would suspect the controller. The only sure way is to insert an amp meter in series with one of the controller lines and measure the current.
Only happens to some and not others. How do I check for carbon. Like what is a sign of it discoloration maybe?
 

D&J RailRoad

Professor of HO
Gawd, that video is nauseating.
Anyway, check your wire connections to the track then check each track connection to each other. When you're tryin to draw current from the power pack to the motor and only a few strands of wire are actually making the connection or contacts between each track section is corroded or dirty, the power pack will heat up. Sorta like a light bulb. The thinner the element, the brighter the light to the point it will burn out.
 

D. Soppy

Member
Only happens to some and not others. How do I check for carbon. Like what is a sign of it discoloration maybe?
You have to get access to the motor and look at where the brushes contact the armature .It should be a copper color. If it is black, then you have a carbon buildup. This is usually caused by oil getting onto the brushes.
 

Trainman2716

New Member
Gawd, that video is nauseating.
Anyway, check your wire connections to the track then check each track connection to each other. When you're tryin to draw current from the power pack to the motor and only a few strands of wire are actually making the connection or contacts between each track section is corroded or dirty, the power pack will heat up. Sorta like a light bulb. The thinner the element, the brighter the light to the point it will burn out.Best I could do
 

JeffH

Well-Known Member
D&J (Ken) is probably right. Sounds like that loco needs some cleaning. A poor electrical connection will cause a motor to draw more power than it would otherwise need. I would start by giving it a bath in contact cleaner, like CRC Electrical Parts Cleaner. It's a sprasy that evaporates quickly and improves electrical "contact."
 

Snowman

Active Member
That's an overheating problem and it's caused by the locomotive's motor asking the powerpack for more current than it can safely deliver. The powerpack's main power transistor is overheating, and the safety circuit kicks in to lower the transistor's temperature...which it does by reducing the current output to the track...and the locomotive comes to a stop.
The overload/safety circuit is operating properly.
If this were a DIY built powerpack (throttle) you could--theoretically--add a larger heatsink to the transistor, but do NOT try that here. That's a sealed case for a reason, and you should leave it that way.
The root cause is a locomotive motor that's asking for more current than the powerpack can safely deliver, and that's what you need to address.

One common, but not commonly diagnosed reason is a geartrain full of hair, carpet threads, dirt, and general gunk. If the bottoms of the trucks are open, so that you can see the gears, and if the locomotive has just been thrown into a box, left on the carpet, etc, then that could be your culprit.
Two options there: 1) The best one is to take the trucks apart, clean the gears and gearbox out *carefully* and clean each gear. Clean out the rest too, using a toothbrush or something similar, and then put it back together again and see if that doesn't fix the issue.
Note: The plastic gears will be made of Delrin, which is a slippery, self-lubricating plastic. You don't need to lubricate it to have it run smoothly...although you CAN...
...which leads to option two: 2) Lubricate an already gunked up geartrain. It goes against all reason to try this, as gunk is possibly what's causing your issue, and lubricants can often just pick up more gunk--which is why there are those well known words of wisdom: "lubricate sparingly"--but
sometimes the opposite can work, provided you use the right sort of lubricant.

I'll suggest this one: https://www.homedepot.com/p/Super-L...ic-Grease-with-Syncolon-PTFE-21030/202932687?
This is a gel, and it won't dry out over the short term.
PTFE is teflon, so it's slippery stuff (!), and it can work where more conventional lubricants pick up gunk, but don't really do much else.

It ALSO has some useful electrical properties--it could really aid with carbon buildup (it works wonders on classic, open can electrical potentiometers when they are spiking), so if you "invest" in a tube @$6.67 (get the grey tube version, not the cheaper one), you can try it on the motor bearings or commutators too, if needed. But take it one step at a time.

Good luck
 

D&J RailRoad

Professor of HO
... If this were a DIY built powerpack (throttle) you could--theoretically--add a larger heatsink to the transistor, but do NOT try that here. That's a sealed case for a reason, and you should leave it that way. ...



Good luck
Why even suggest that to the guy? He sounds like he really has no experience what so ever in electrics.
 
D&J (Ken) is probably right. Sounds like that loco needs some cleaning. A poor electrical connection will cause a motor to draw more power than it would otherwise need. I would start by giving it a bath in contact cleaner, like CRC Electrical Parts Cleaner. It's a sprasy that evaporates quickly and improves electrical "contact."
Yes, CRC Electrical Parts Cleaner is safe for plastics. Do NOT use Brake Clean, or other cleaning solvents, unless they specifically say "safe for plastics". I have some brake cleaner at home that is definitely not safe for plastics (don't ask me how I know :oops:).

Clean everything, and lightly lube the mechanism. Make sure nothing is binding or rubbing, causing excess power draw.

Also, your transformer may be getting faulty and putting out less than adequate power. Although it's Athearn, it looks a LOT like MRC Railpower transformers. I have had a few of them start going bad for no apparent reason. You might want to check the output on it if you have the capability.
 

trailrider

Well-Known Member
Question: Have these same locomotives always had this problem? How old are they? I have a number of Athearn Blue Box F7's that would do this with a DC power pack, especially if I tried running two powered units together. Stall current on each of these was in excess of 1.5amps even when I cleaned the commutators and wheels. The current draw was more than the pack could handle after a while. My solution was to invest in a more powerful (higher amperage rating) power pack. The other possibility would be to re-motor the locomotive with a can motor with a lower current draw.
 




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