Hi hi! I've got a number of N scale brass locos that I am slowly converting to can motors, adding headlights, and the like, and adding DCC decoders as I get to them. However, I have one loco in particular, a Key NYC light Mikado, that simply due to its design makes the installation more complicated than normal. It currently has a good Mashima open frame motor in it, which runs well and quietly. However, I know the motors must be isolated from the frame; does the motor housing have to be isolated, or do the windings simply not have to be common to the frame? If the latter I can use the motor as is; it's mounted to an L shaped mount by its frame, thus the frame is electrically live as the track power is applied, but I can isolate the windings within fine. Is this sufficient? If I mount a can motor the same way (by the L shaped bracket) its housing is thus now common with the frame, but again, the windings within are isolated from the can and frame; is this ok? I guess I am just unsure what "the motor must be isolated from the frame" means. The motor's stator wiring? Or the motor's frame, even if the frame itself is isolated from the stator winding? All the best, Amanda
Sounds like the Fleischmann round motors They also work on a live chasis but the armature and brushes is isolated from the frame. On the older models you have to cut some traces on the motor coverplate and even older ones you also have to remove the brush holder that is conected directly to the coverplate and modify (file a bit down) it not to touch the plate and cause a DCC short. The new models is DCC friendly. Upside is you don't have to use the blue decoder wire with lights. The safest way is if the motor is isolated, but having the armature and brushes isolated should also work.
Thank you! I could swap to a can motor in this one (and isolate the can motor housing in my H10) but that involves... a lot of work. If I do not need to do that, it saves me a lot of headaches.
If you do a contuinity test on your 2 power input points on the motor you wil find one is isolated from the motor cover while the other one most likely not. That one also needs to be isolated, but that will be up to how the motor has been put together. You can also use the life frame to connect the black wire of the decoder to and the red one to the wheels. Less wiring. Also possible to cut out the blue wire on lighting.
Hi Pieter, I did check for continuity between the frame and the terminals, and there is no continuity there. This means it's DCC ok, right?
Should be fine if it is isolated - no shorts. Orange & Grey wire to each terminal (which way around your choise of direction of travel). Black wire to somewhere on the live frame and red to the isolated wheel set. Check for unintentional solder bridging. I would suggest put it then on a track and let it just stand for a short while and to check if the decoder becomes very hot or if the CS trips. Then see if it moves. If all we'll finish instalation. Had last week an engine that kept on tripping. Took the shell of and it works fine put it back and will work for a while and then trip again. Eventually found Fleischmann had a wiper coming up in the frame from one side of the wheel and now and again it touched the live frame - short. One side of it wasn't isolated.
Also, When testing on track, it is usually better to test on a programming track than a main track as most programmers / command centers limit the current on the programming track so if you do have problems you are less likely to fry a decoder.
