lionelsoni That result tells me that the problem is not a short circuit, but that the locomotive is drawing an amount of current that is right on the edge of what the modern transformer can supply. It probably has a "foldback" overcurrent protection circuit, which is designed to reduce the current when it trips and stay that way, with only a small current flowing, until you reset it by shutting the voltage down. Since your locomotive seems to be drawing just barely enough current to trip the foldback, it might be possible to solve the problem my getting it to run just a little more easily.
That result tells me that the problem is not a short circuit, but that the locomotive is drawing an amount of current that is right on the edge of what the modern transformer can supply. It probably has a "foldback" overcurrent protection circuit, which is designed to reduce the current when it trips and stay that way, with only a small current flowing, until you reset it by shutting the voltage down.
Since your locomotive seems to be drawing just barely enough current to trip the foldback, it might be possible to solve the problem my getting it to run just a little more easily.
--Dan
Bob Nelson
lionelsoni To verify that the problem is electrical, I suggest that you get hold of a real, traditional transformer with a thermal circuit breaker, the bigger the better, and try to run with that. If the locomotive still stops intermittently, despite having ample current in the short term, then you can be confident that the problem is truly a short circuit; and no amount of cleaning and lubrication will help.
To verify that the problem is electrical, I suggest that you get hold of a real, traditional transformer with a thermal circuit breaker, the bigger the better, and try to run with that. If the locomotive still stops intermittently, despite having ample current in the short term, then you can be confident that the problem is truly a short circuit; and no amount of cleaning and lubrication will help.
On a (mostly) unrelated note, does anyone recall the value of a 1952 Marx 495? Mine's in rough shape, and I'm trying to decide whether or not to bother restoring it or rebuilding it according to my desires.
GG1 guy Super easy way to check a Marx armature-remove it from the motor and clean it if necessary. Take a simple volt/ohmmeter and make sure it is set to read resistance (ohms). Put one test lead point on one of the three copper surfaces of the armature, and the other to either of the other two sections of the armature. It should read about 1.1 ohms. Any two sections of the armature should read this resistance-if it does not, repair or replace the armature.
Super easy way to check a Marx armature-remove it from the motor and clean it if necessary. Take a simple volt/ohmmeter and make sure it is set to read resistance (ohms). Put one test lead point on one of the three copper surfaces of the armature, and the other to either of the other two sections of the armature. It should read about 1.1 ohms. Any two sections of the armature should read this resistance-if it does not, repair or replace the armature.
I see no clear reason why I should grow up...
DFD26 KRM I am thinking a armature problem with heat???? "And last check the armature to be sure it is not shorting out." Hi Kev, what do you do, specifically, to check your armatures for shorts? Thanks.
KRM I am thinking a armature problem with heat????
I am thinking a armature problem with heat????
"And last check the armature to be sure it is not shorting out." Hi Kev, what do you do, specifically, to check your armatures for shorts? Thanks.
Go here,
http://cs.trains.com/ctt/f/95/p/216725/2384261.aspx#2384261
Joined 1-21-2011 TCA 13-68614
Kev, From The North Bluff Above Marseilles IL.
lionelsoni When you write "short", do you mean that you know that there is an actual short circuit, as opposed to an overcurrent that may be slightly more than the transformer will tolerate?
When you write "short", do you mean that you know that there is an actual short circuit, as opposed to an overcurrent that may be slightly more than the transformer will tolerate?
I like that! Thanks! I did spray down the whole unit with CRC non residual electronic cleaner, took apart the brush plate, cleaned the brushes, the armature, got out the carpet fibers from the previous owner, etc., and relubed everything. At first it ran like a watch. Then, over time, it started to do the "cold short - warm up fine" problem I had described. I was just wondering if this was someting idiosyncratic of Marx tinplate motors. My Lionel prewar No. 248 doesn't have this problem. Thanks for all the input. I'm still learning how best to clean my engines.
If you are still having problems, check to make sure the brush springs are in good condition and appying even tension to the brushes. Also give the eunit a good spritzing with contact cleaner. It's like chicken soup - it can't hurt!
DFD26 Thank you Kev, I will check what you suggested. I gave the brush plate, armature, and brushes a good cleaning as well as the wheels and track. However, the wires and other items you suggested are worth an inspection. Thanks again! --Dan
Thank you Kev, I will check what you suggested. I gave the brush plate, armature, and brushes a good cleaning as well as the wheels and track. However, the wires and other items you suggested are worth an inspection. Thanks again! --Dan
Hi DFD26,
It could be a lot of things but here is what I would look for first. Pull the motor out of the shell. Check for loose or cracked wires from the pick up to the e-unit and from the e-unit to the motor. Check that the pick- up is not sloppy and shifting side to side. Make sure the drive wheels are nice and clean and getting a good contact to the track. I clean mine by running the motor upside down and running a fingernail file or some fine emery paper over the wheels till they shine. Pull the brush plate and clean the brushes and armature. And last check the armature to be sure it is not shorting out. Hope this helps.
I'm confused. More often than not, when my Marx 999 starts up cold, it registers a blinking "short" on the green light of my Lionel transformer. After a few restarts, the locomotive begins to run perfectly with no "short" with lots of power. I've cleaned and lubed the locomotive. What gives?
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