I bought a used LMB H10 Mikado with a Sagami 1630 a few months back and have been running it significantly since then. The engine ran smooth and had no issues the whole time I have had it. At first I was pulling a train of all 36 foot hopper cars with about 15 cars on it. It is a mostly flat layout (the benchwork is not perfect so there is a real slight grade in the one corner). Later on I switched it to pull a mixed freight train of about 22 cars. It runs in continuous operation when hooked to a train and occasionally I change trains out. At any respect I was running it tonight and noticed that it seemed to be running alittle slower than usual. Well I was paying attention to my 15 month old son who was enamored with my coal tower for a few minutes and when I looked back at that train it was stopped with the light on. I later brought it down to my testing area, took the boiler off, and put power directly to the motor and nothing. I know I was making a good contact as I tried sparking the ground / power drawbar with opposite power wires.
So my questions is this… what caused it to die on me? Can these motors be opened easily or are there a million tiny ball bearings like in the old square style Rivarossi motors? I absolutely loved how slow and smooth running this engine was, but with the motor burned up its not good for much of anything. My transformers are all old basic linear power supplies… step down transformer going through all new replaced bridge rectifiers (the original celenium ones went bad) and a wound variable resistor to set the voltage to the tracks. There is probably some decent ripple on the track from that configuration but it doesn’t seem to bother any of my Bowser / Mantua / Athearn locomotives. Any thoughts?
The ripple from your power supply is probably the long term culprit. The supply you describe would put a hefty heat load into a can motor like a Sagami 1630.
If you do not want to burn up more motors, I suggest you put some capacitance on the output side of your bridge rectifiers, a few thousand microfarads would do wonders. A couple of the 50V 3300 microfarad ones from here would work well - make sure you get the polarity correct:
Sagami motors use your typical sleeve bearings, so there’s no worry of dropping tiny BBs everywhere. It looks like the endcap is held on by a couple pins stamped into the motor case, so it shouldn’t be hard to open. The problem could be something as simple as the brush springs relaxing from age, which can be fixed with a tiny bit of bending.
You may also want to smooth out your DC signal before running any high quality equipment again. Many motors and electronics don’t like a pulsing DC signal, like basic bridge rectifiers will put out (which is a 120Hz wave like this: _////). Smooth filtered DC will make everything work a whole lot better, except for lower speeds (a pulsing signal always helps at very low speeds). My coreless motor powered engines and some of my lighting circuits work very poorly with pulsing signals.
First, I have to say I’m not sure there is enough information to determine even if the motor has failed, much less what caused the motor to fail.
I don’t buy the power ripple theory without some evidence of sustained over-heating. Every standard power pack without special pulse injection circuitry and filtering has the same ripple. The Sagami 1630 is not a tiny can motor, and it was one of the better Sagami designs/motors (according to some brass loco rebuilders other Sagami models/designs were not as strong).
Low frequency (typically 60Hz) pulses with a square form are the best for ultimate low speed running, and the most likely to cause overheating. Users of pulse width modulation and similar square pulse techniques learned, and now generally use a much higher pulse frequency (1K-3K or even higher). The higher pulse frequency reduces heat problems and eliminates the growl and noise of the 60Hz pulses. A standard power pack with full wave rectification, but without filtering, has a rounded 120Hz pulse, which is not known for over-heating anything except perhaps very sensitive coreless motors.
The overheating process for a motor can have several paths. First, the entire motor gets very hot but otherwise stays intact, which causes the magnets to lose some of their strength. With weakened magnets, the motor requires more current for the same torque, which produces even more heat. Another path of destruction is when the windings get too hot, and the insulation burns/melts, causing internal shorts in the windings. This reduces the resistance of the windings, thereby increasing the current and the heat until the motor fails. Usually, there is some smell associated with burning windings. Or the brushes can melt/fuse with the high current/heat, causing them to lose solid contact with the commutator. Again, some smell is likely. Finally, the excess heat c
With an ohm meter check the motor resistance. If resistance, then remove the motor and try with power. Might just be the current draw was to much for the motor.
I overloaded a Sagami and I have opened up a Sagami 1620 motor and it is a real bear to get back together. Never had any success. Doubt NWSL would have brushes if that is the problem.
My club has run DC with pulse power for many years and no motor ever went bad. Many people use DC with pulse power. Some packs have 120 Hz pulse power. Some might have 60 Hz pulse power. Been many years since I have used pulse power or discussed it with anyone.
All DCC decoders send pulse power to the motors that many people are not aware of.
The only issue with pulse power is coreless motors from some discussions I have read. I don’t use coreless so have not looked into details on this issue.
I finally got to work on the engine today. I took the motor off and checked for voltage while turning the armiture (a perminant magnet motor will generate DC when spun, which it becomes a generator) and I got nothing. I then tried the trick someone above mentioned using an ohm meter and I read infinite. So I took the back cover off and one of the brushes fell out. Upon examination the wire that holds the brush on came apart. Any idea if those wires / brushes are still available?
I just received some driver springs from NWSL and Dave included a paper catalog. The 1630 motor is sold out right now, at least that is what I saw in the paper work.