Fidelio

Finally -- some findings to report! I purchased a small number of 12V "flat" motors from eBay and AliExpress that had dimensions 30mm X 24mm X 18mm or smaller; the cost varied between $1.50 and $3.00 (USD) each. The shaft diameter of the motors is 2mm so to maintain compatibility with the Bühler gear. I also bought some replacement gears in case I couldn't remove the gear from the original motor. You can use a 0.4 modulus gear for interfacing with the original cog (4V motor interface), or a 0.5 modulus gear for the larger cog (12V motor interface); both have 9 teeth. The gears were by far the trickiest parts to find as it was difficult to measure them and find a seller with gears of similar measurement. The 0.4M gear was not as readily-available as the 0.5M gear and I was only able to find the former in brass. The 0.5M gears are available in both brass and vinyl, and are the least expensive of all; a bag of 10 vinyl gears was less than $2.00 (USD) shipped -- the same cost for a single brass 0.4M gear. Before buying a gear, measure the diameter and length in mm of the original gear and compare with what the sellers claims, just to make sure the modulus isn't misreported. Once you have your parts, it is really just a matter of milling the motor casing and adjusting the position of the gear on the motor shaft to ensure a snug fit in the Lego motor chassis. This is by far the most time consuming part, and was mostly trial and error for me. Unexpectedly, the RPM of the new motor is much higher than the original 4V motor and thus produces A LOT of noise when run at a full 9V. I noticed that there is some minor vibration of all the gears in the chassis when using the original motor and so that vibration becomes amplified when run at a higher RPM.

Does anyone have any specs on the capacitor and self-resetting fuse? I imagine there are all fairly standard components, perhaps a 100nF capacitor for noise filtering and 2A or less current limiting fuse. I'm looking to fit a similar circuit to an existing motor and wanted to replicate the setup as much as possible to protect the upstream Powered Up circuitry.

I've been doing a bit of research into sourcing a different motor as Conrad is somewhat inaccessible to buyers in North America. That said, the Motraxx 263 motor specs are fantastic as it can operate on a wide voltage range which is suitable for speed control. If you're in Europe, this motor should certainly be at the top of your list! The standard motor dimensions for 12V "flat" motors appear to be (LxWxH) 30mm X 24mm X 18mm and there are several manufacturers that make this size motor; Mitsumi M24N-1 and Mabuchi FK-280 are some models that I found, both available on eBay and in the $5 or less price range. From the "Railbricks 6" article, we can see that the Motraxx 263 is a bit smaller than the Bühler motor, and the specs for the Motraxx 263 give it a 27mm length. This suggests that any of the standard sized "flat" motors should also fit in the 810 motor chassis with similar modifications. I plan to buy some of these motors for experimenting and will report back with my findings!

This is fantastic! Thank you for sharing the Rail Bricks article!

Hi everyone! I recently rediscovered my old 7715 train set and accompanying 810 motor set -- the motor and gears work perfectly after well over 30 years of storage! That said, I started thinking about upgrading the internal 4.5V motor to 9V or 12V as it will allow me to build an adapter and leverage some existing electronics (i.e. Powered Up). Has anyone found any off-the-shelf 9V or 12V motors that will fit into the chassis with little-to-no modification? Of course I could just buy a modern 9V train motor, but I would lose the red-wheels that match the decor of the locomotive. Here is a photo of the motor from the 810 set; note that this uses a 4V Bühler DC motor, which can be directly replaced with the 12V Bühler DC motor of the same era. I found the following post detailing a modification of a similar chassis, but it looks to be from a different motor set. It appears that there are several 4.5/9/12V motor kits that use similar chassis, but with different internals/gearing. Finally, it looks like the 9V Lego M Power Functions motor from set 8883 may be a suitable candidate, though the driving cog might not align with the gears in the 810 motor. Any help in finding a compatible DC motor would be appreciated! Totally ready to resign to buying a new 9V Powered-Up motor and work with that too :)

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