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Discussion Starter · #21 ·
A basic understanding of electronics is needed before making some of the statements you have both made.

First: faulty circuit breaker: that Bridgewerks will deliver 15 amps all day. If you have a SITUATION where you are drawing 15 amps, it will go on FOREVER and the circuit breaker will not trip, and well it should not.

If you manage to put the loco in a SITUATION where it DRAWS 15 amps, you will indeed destroy something.

The lack of understanding here is how to make the SITUATION where you can DRAW 15 amps. Clearly with the wheels turning, it was not drawing 15 amps, 15 amps going through that motor would destroy stuff. So there is NOTHING wrong with the circuit breaker.

Current is drawn in proportion to the voltage and resistance in the circuit. Please read about Ohms Law.

So, in the NORMAL SITUATION, the motor's resistance is such that it will only DRAW about 1 ampere... so no damage will occur. (you could have a 1 million ampere supply and this would still be the same)

Now, if the VOLTAGE from the Bridgewerks suddenly went almost triple, that would triple the current, i.e. the locomotive would DRAW more amps, and this could damage it.

locking or impeding the drive train will reduce the resistance of the motor and then it will DRAW more amperage, and that is a common mode of damage, BUT you say the wheels were turning... (this part of the story does not compute)

a SHORT CIRCUIT, i.e. bypassing the motor (the circuit becomes shorter) would DRAW a lot of current, and normally exceed the 15 amp rating and then the circuit breaker would trip, BUT you say the wheels were turning, so there was NO short circuit.

Again, the story still does not "jive" with what happened... it the loco was mechanically stalled or "binding" the story would make sense, or a short circuit somewhere... BUT if the loco derailed and the wheels were turning it cannot be..

Is there any chance that the wheels were turning, but really slowly and binding? This is about the only guess I can make where you could draw a lot more current to cause the motor / brushes to be damaged.

Greg
Greg,

Really appreciate your explanation and with you explaining Ohms Law, it makes sense that the engine would only draw current in proportion to the voltage and resistance in the circuit.
The question then becomes, what caused the engine to pull up to 15 amps because if it pulled more, the circuit breaker on the Bridgewerks would have tripped but since it was not tripped
the amps did not exceed 15 but that would destroy stuff like the motor and gears. Engine had a strong burnt smell.
The wheels were turning but slowly so I think you have pinpointed the problem. The drive train was impeded during the derailment reducing the resistance of the motor which caused it to draw
more amperage which could have gone up to 15 amps with my Bridgewerks which would have caused the motor and gears to burn out.
With the problem probably identified in that it was not a short circuit and that it doesn't matter how big a transformer I have because of Ohms Law, it sounds like Pete had a great suggestion when
he suggested I put a 3 amp polyswitch in one leg of the connectors between the transformer and track. This would pop at 3 amps and save the motor from burning out because of the extra amps the engine is calling for because of the binding of the wheels or impending the drive train.
Does that make sense?
 

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Yes, the wheels turning slowly could be a heavy load, hard to gauge, but the rest of the symptoms sure look like overloading the motor.

The trick will be to choose a polyswitch that will tolerate "normal running" but trip above that.

This may be a bit of work for you, since there is indeed a "fast blow" version of the polyswitch, but few people other than electrical engineers know about that model.

It will probably require you to go to Mouser or Digi-Key to get...

Also 3 amps will be too much, you may have to experiment, you want the lowest current model that allows normal operation of the loco, so you may have to buy several different values to get the one that meets your need, this is a fine line. 3 amps will be too much on the LGB motors, since they cannot handle gobs of current like the Aristo Craft locos that have 3 amp ones, they have fan cooled, high current motors as compared to your LGB

I would try ones from 1.5 amps to 2 amps at first, and the fast blow variety. The correct experiment is to find the lowest rated one that works in normal operation, so that means keep going down in value until it trips prematurely, and then go up one "step" in current rating. Again, your goal will be harder since the LGB motors are already low current and do not have a high tolerance for high current.

If one of my engineers was doing this, they would measure the current drawn under normal circumstances, and then pick one with the appropriate "hold current" (you will see this in the link).


Good luck. I would wonder if you could not do something else to avoid derailments also, but I'm sure you are full up with advice now!

Regards, Greg
 

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Discussion Starter · #23 ·
Greg,

Really appreciate your explanation and with you explaining Ohms Law, it makes sense that the engine would only draw current in proportion to the voltage and resistance in the circuit.
The question then becomes, what caused the engine to pull up to 15 amps because if it pulled more, the circuit breaker on the Bridgewerks would have tripped but since it was not tripped
the amps did not exceed 15 but that would destroy stuff like the motor and gears. Engine had a strong burnt smell.
The wheels were turning but slowly so I think you have pinpointed the problem. The drive train was impeded during the derailment reducing the resistance of the motor which caused it to draw
more amperage which could have gone up to 15 amps with my Bridgewerks which would have caused the motor and gears to burn out.
With the problem probably identified in that it was not a short circuit and that it doesn't matter how big a transformer I have because of Ohms Law, it sounds like Pete had a great suggestion when
he suggested I put a 3 amp polyswitch in one leg of the connectors between the transformer and track. This would pop at 3 amps and save the motor from burning out because of the extra amps the engine is calling for because of the binding of the wheels or impending the drive train.
Does that make sense?
Yes, the wheels turning slowly could be a heavy load, hard to gauge, but the rest of the symptoms sure look like overloading the motor.

The trick will be to choose a polyswitch that will tolerate "normal running" but trip above that.

This may be a bit of work for you, since there is indeed a "fast blow" version of the polyswitch, but few people other than electrical engineers know about that model.

It will probably require you to go to Mouser or Digi-Key to get...

Also 3 amps will be too much, you may have to experiment, you want the lowest current model that allows normal operation of the loco, so you may have to buy several different values to get the one that meets your need, this is a fine line. 3 amps will be too much on the LGB motors, since they cannot handle gobs of current like the Aristo Craft locos that have 3 amp ones, they have fan cooled, high current motors as compared to your LGB

I would try ones from 1.5 amps to 2 amps at first, and the fast blow variety. The correct experiment is to find the lowest rated one that works in normal operation, so that means keep going down in value until it trips prematurely, and then go up one "step" in current rating. Again, your goal will be harder since the LGB motors are already low current and do not have a high tolerance for high current.

If one of my engineers was doing this, they would measure the current drawn under normal circumstances, and then pick one with the appropriate "hold current" (you will see this in the link).


Good luck. I would wonder if you could not do something else to avoid derailments also, but I'm sure you are full up with advice now!

Regards, Greg
Greg,

Thank you for your time and comments. Based on your expertise, I'm sure what you have described is causing the LGB to overload and burn up. Thanks for the link.
Will go with the 1.5 amps and 2 amps with the fast blow variety and see which one works.
As far as the derailment issue, I have tried to solve that problem. Problem is the engine could run for 6 hours a day for days at a time and be fine. Then it would derail. I live in Michigan
so this could be from snow on the track or some ice or maybe a bit of wind. Derailment always occurs at the turns and will just happen once in a while but if the sliders are still in contact
with the track, the motor will overload and burn out. Really appreciate you analyzing and coming up with the source of the problem which included that it was not the size of the transformer. Makes perfect sense. The solution is even better as it should solve my problem. Thanks again.
take care of the problem.
 

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Another possible issue is the SR 15 can output over 30 volts if the Black plate limiting the voltage is moved to the very top. I have seen this type of supply short the LM317 regulator and place 38 volts on the track as well as the throttle when the black plate is positioned at the top. The electronics in the LGB products will not tolerate this voltage and many things can 'burn' out/up. Note, I have no experience with the remote throttle unit.
 

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Discussion Starter · #25 ·
Another possible issue is the SR 15 can output over 30 volts if the Black plate limiting the voltage is moved to the very top. I have seen this type of supply short the LM317 regulator and place 38 volts on the track as well as the throttle when the black plate is positioned at the top. The electronics in the LGB products will not tolerate this voltage and many things can 'burn' out/up. Note, I have no experience with the remote throttle unit.
Thanks again for your comments.
 

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The older, original Bridgewerks were often guilty of high voltages in lightly loaded conditions.

But the new owner has corrected the problem and added circuitry to help control this. There is a way to spot this, and if you have an old style one, the new circuitry can be retrofitted.

Please scroll down to the Bridgewerks section: (with the new circuitry, I can recommend this product)


Greg
 

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I still can't picture a situation where the Loco derails because but the sliders stay on the track. Guess I would need to see a picture.
 

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I could see one slider... and I guess you could put the wheels on the ground so to speak and have sliders contact maybe at a switch, but I agree, pretty hard to figure out.

Maybe one slider, and the other wheels?

Greg
 

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Discussion Starter · #29 ·
The older, original Bridgewerks were often guilty of high voltages in lightly loaded conditions.

But the new owner has corrected the problem and added circuitry to help control this. There is a way to spot this, and if you have an old style one, the new circuitry can be retrofitted.

Please scroll down to the Bridgewerks section: (with the new circuitry, I can recommend this product)


Greg
Greg,

My 15 amp Bridgewerks is only a year old so it would have the new circuitry but as you pointed out, what was causing the motor to burn out was when the engine derailed and the sliders were still on the track, the wheels were binding and as the motor called for more voltage, the motor burnt out.
 

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Discussion Starter · #30 ·
I could see one slider... and I guess you could put the wheels on the ground so to speak and have sliders contact maybe at a switch, but I agree, pretty hard to figure out.

Maybe one slider, and the other wheels?

Greg
What happened on the 2 engines I lost due to this situation was that on a turn on my oval track, which has runs of 10 ft., meaning the turns are not that sharp, the front wheels were spinning and binding when the engine derailed. The engine was cocked just enough where the left and right front wheels were spinning and binding with one wheel just outside the rail and the other just inside the other rail. Since the sliders sit in back of the front wheels, they were still making contact with the rails and drawing the voltage. As you pointed out Greg, this caused the motor to seek more voltage because of the binding and when the amps exceeded the 1 amp that the engine usually draws, the motor burnt out. Am going to use your suggestion and link you provided to use the 1.5 amp or 2 amp fuse between the transformer and track which would prevent the motor from burning out when this happens again.
 

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I think you are on the right path, it may take a bit of experimentation, but it's the best I can come up with for ideas.

The only other thing would require more work, like some kind of thermal cutout on the motor itself. It would have to be adjustable, etc.

Fingers crossed for your success!

Greg
 

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Discussion Starter · #32 ·
I think you are on the right path, it may take a bit of experimentation, but it's the best I can come up with for ideas.

The only other thing would require more work, like some kind of thermal cutout on the motor itself. It would have to be adjustable, etc.

Fingers crossed for your success!

Greg
I think you are on the right path, it may take a bit of experimentation, but it's the best I can come up with for ideas.

The only other thing would require more work, like some kind of thermal cutout on the motor itself. It would have to be adjustable, etc.

Fingers crossed for your success!

Greg
Greg,

I really appreciate the time and effort you put in to help me. Was really nice of you. I won't be setting up the train until after Thanksgiving but I will be ready.
Will splice the 2 lines going to the track from the transformer and put in the fuse. Will experiment with the lowest rated trip rating until the engine runs smooth without the fuse
tripping. Thanks again.
 

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If you get stuck when you go forwards, you can email me privately too. Getting parts from Mouser can be fun, and I can help with that.

Greg
 

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Greg, I think these newer MLGB Stainz do not quite have the motor durablity of the older versions prior to Marklin taking over. I have seen more issues with newer version of this engine than the older Lehman built version that were known for being down right bulletproof, even with being submerged into ponds. I do agree he needs to also look into the spot it derails and take care of any track issues at hand. Along with the fast acting fuse to protect the engine should a derailment happen in the future. Make sure to post up some pics of this years holiday layout. I know I would love to see some pics or even video of your display. Good luck
 

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Discussion Starter · #36 ·
Mike,

Thanks for your response. Am in the process of purchasing resettable fuses with a 1.55A run rate and and a 2.67 trip rate. As Greg has walked me through this, hopefully with a derailment in which the pickup sliders are still on the track drawing electricity to the motor but a wheel isn't causing the wheels to bind and burn the engine out, the resettable fuse will trip and save the motor.
I have an oval track with 10 foot runs. The derailment occurs at one of the four turns. I'm in Michigan and around Christmas it gets cold and icy with the wind blowing. I think what happens is
a gust of wind or ice will cause just enough disturbance to knock a wheel off the track but not the sliders causing the motor to burn up because it is being run unattended.
A few years back, Valero Oil Company did a TV commercial on my Christmas display. Doesn't show the train and track but shows you the display. Attached is the link.

Thanks,
Mark
 

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I would gamble that the wind blows something onto the track, chunk of ice, a small stick ect. That would derail the Stainz.
 

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Discussion Starter · #38 ·
I agree with you. That is why I hope the resettable fuse will solve the problem. With the wind blowing obstacles on the track causing derailing, I wouldn't be able to completely solve this
problem with the train running unsupervised.
 
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