I have an 18x12 oval running around the top of my office. Double track mainline with no cross overs.
I have an Athearn Genesis SD45-2 model with a Soundtraxx non-sound decoder. Loco is running solo with no cars. No other locos on either track. After running for a few minutes, the loco with begin to run very herky-jerky and then eventually stop. I'm guessing the decoder is shutting down before over heating. While testing the model with the shell off, I noticed that the motor was HOT.
I'm running a MRC Prodigy Advance system with a MRC 8-amp power booster.
I have the booster connected to 14 gauge wires, which are fed through a terminal strip splitting into multiple sections going through 4 DCC Specialties PSX-1 circuit breakers. Each track is split into two isolated sections and each track has a dedicated bus line with 18 gauge feeder wires every 30 inches.
When I measure the track voltage with a RRAmpmeter, its reading between 14.9 and 15.1 volts.
While I haven't outright tested other locomotives out of fear of destroying DCC decoders, looking back I have noticed similar performance from other Athearn Genesis locomotives with Digitrax decoders.
This leads me to believe that its not the locos or DCC decoders but rather something with the system.
Any ideas on the cause of this? Is the voltage too high? Is it possible the MRC system / booster have gone bad?
If your meter will measure DCC voltage will it measure DCC current? If so check the current draw of the locomotive in question, at normal running speeds the current should be well under one amp.About the only thing that would make the motor run hot is too much load. Make sure the locomotive isn’t binding up somewhere putting extra load on the motor.Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Duke249 I have noticed similar performance from other Athearn Genesis locomotives with Digitrax decoders.
I don't recall anyone with a similar observation.
When I got back into the hobby, 5 or 6 years ago, I recall reading about some Soundtraxx decoders running hot.
More recently Rapido had a motor problem with their RS18? the details of which I don't recall, but they did a youtube video on it.
Your voltage sounds good and an 8 amp system doesn't force more amps than a properly functioning loco asks for. (If there is a short, well that's why you have circuit breakers, though they don't guarantee the decoder won't fry.
If there is some binding in the gear train, that would make the motor draw more current and get hot.
Henry
COB Potomac & Northern
Shenandoah Valley
I’m pretty sure the problem is internal in the locomotive. Do the lights work normal? Does the throttle work OK. I can’t think of anything that could go bad in a DCC system that would cause the motor to over heat.Try running a second locomotive to make sure your Prodigy is working OK. Has this locomotive worked OK earlier then had problems?Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Athearn has not been immune to bad motors:
ATH_DC-motor1 by Edmund, on Flickr
The best way to disagnose this is to isolate the motor from the decoder and run the motor on pure DC with a good ammeter in the circuit. A set of test rollers is helpful as is a good DC supply with metered outputs.
Good luck, Ed
I've been running a number of different locomotives today and have found no issues with any. Therefore, it looks like you guys are correct in that its the genesis model that is having the problem.
I haven't had time to test the motor. Hopefully I'll get to that this weekend!
Thank you for the quick replies!
A hot motor is an amperage issue, not an overvoltage concern.
In DCC, the supply voltage has little to do with what the motor 'gets'. These are voltage-controlled motors, so the decoder synthesizes the voltage necessary to make the motor turn, and the locomotive run, at a particular speed.
Amps are drawn, not forced. That means that the 'ampacity' has nothing to do with "forcing" the motor to do anything; more amps just means more reserve on which the motor can draw if it needs Moar Power.
What this translates to is that a hot motor is an overloaded motor, not an "overpowered one", and you should identify the reason(s) the motor is drawing high current and repair them. Some of these might be within the motor structure itself, so be prepared to understand how your particular motor works. If it has been chronically overheated and it is a permanent-magnet motor you may in fact have weakened the magnets 'permanently' which induces a vicious cycle as the now-weaker field requires higher and higher armature current to make the same armature torque.
Have you tried test running the engine on DC to see if it heats up that way too?
I'd also check if there could be some sort of minor short somewhere. Is this like a lightboard replacement decoder, or is the decoder plugged into a lightboard sitting on top of the motor? Sometimes one of them will have tiny metal parts on the bottom that can touch the top of the motor and cause problems.
I installed a Soundtrack decoder with sound in an engine. The instructions specifically said the decoder ran hot. It was not the motor, but the decoder. The engine shell got warm, and that was noticeable. Apparently, Soundtrack considered this normal.
It takes an iron man to play with a toy iron horse.
Warmth through the shell from the decoder is one thing; having the motor HOT (see original post) is something different.
Permanent-magnet DC motors suffer when the magnet material is repeatedly heat-cycled to and beyond its Curie point. Most of the time it isn't possible to recover the flux density, and it is definitely impractical to R&R most of these magnets.
Many motor shops will happily take your money to 'rebuild' voltage-controlled permag DC motors. They happily take them apart, check the armature winding and balance, stone and clean the commutator, replace the bearings, etc. ... then blink at you when you complain the rebuilt motor performs no better, or cooler, than it did before.