PRR5406 wrote: ↑Fri Aug 19, 2022 7:33 am
Friends at Quebec Live Steamers constructed electric switch motors from dead portable electric drills. So many battery powered drills lose the batteries and then the manufacturer changes the battery design. Salvaging the drills and motors became an option for these folks.
As stated in my original post, one of the requirements I have for the switch motor is:
Must have a low current draw to allow it to be fed by long wires at a distant point on the railroad without the need for batteries, etc. Obviously it could still be used with batteries if desired. I want to keep the current under 100ma but my target is 30ma-40ma
The drill motors you refer to draw several amps on startup, have large running current, and a large current draw if the motor is 'stalled' (can't move). They will work where large current is available (mains, solar charged battery, etc.) but can not be used, for example, 1,000 feet away from the signal system power source without using very large power conductors.
The obvious advantage of the drill motors is that they are available very inexpensively in many cases.
In my case, since I will be selling this as a 'product', I can not base the design on a 'surplus' motor that might not be available tomorrow. The motor I am using is produced by several different sources and my mounting is designed such that it is not difficult to substitute similar motors in the same size range (about 1.25" diam x 2.5" long).
The motors I use are drawing about 35ma in testing. These switch motors can be used a long distance from the power source. In the case of the signal system I sell
http://MiniRailSolutions.com which uses a single 30 volt DC central supply, these switch motors can be 1,000's of feet from the supply. Two of my customers have power/data runs exceeding 3,000-4,000 feet with over 60 signals and a supply current less than 2A total.
Due to the low current, I also plan on selling a version that has a self-contained small rechargeable battery and a solar cell. This unit can be used stand-alone away from any power source.