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Discussion Starter #1
I bought a Timpco slow speed DC can motor to install in my AF 312. locomotive. When I bench tested the DC motor with the two motor screws tightened, I have to turn the transformer more than half way to get the locomotive to move. If I loosen the screws up some then it will move at around a quarter of the way turned up. Looks to be a miss alignment problem. I was told to leave the original brass bushing in for the motor gear shaft. I tried to shim it with some shim stock. Just trying to get the DC motor to run free. Does anyone have any tricks to align the motor to the chassis ? Thanks Strainguy
 

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This has been discussed in the past. First the answer, its trial and error. The problem you are trying to solve is that the pitch on the half speed worm is 1/2 of the pitch of the factory worm. As a result the tooth angle on the driven gear is now incorrect. Some engines run perfect after the change, some barely run at all. It seems to depend on the amount of wear on the driven gear teeth, the wear on the axle bearings, the exact alignment and position of the worm gear and the depth of engagement between the worm and sector gears. There is also a lot more friction between the worm and sector gear because the worm is now spinning twice as fast as it was before in addition to the incorrectly shaped sector gear teeth.
 

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No help here. I thought about a can motor conversion on a engine I was having trouble with. I was able to repair the engine and never did the conversion. So I have no experience with a can motor.
It does sound like you have an alignment problem. Maybe try some shims. Just curious, why
you were going to a can motor.
 

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Discussion Starter #4
I have found a solution to the can motor conversion that may or may not work over time, we will see. The armature bushing in the chassis was causing the can motor shaft to drag, took more power to turn. I removed the bushing and now it runs free. Like i said early, for how long ? who knows ?

The reason I went to a can motor is convert to 12 Volts so i can do some switching and eventually convert to DCC w/sound. These locomotives on 12 volt run very smooth and slow without the jerk when first starting the locomotive.
 

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Keep it lubricated and hopefully it will last. When you install the DCC controller it might not be necessary to have the half speed worm gear any longer. The original worm can be put on the shaft and the alignment problems will be permanently cured.
 
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