Kysan DC Gearmotor Teardown
We’ve been using GM3 gearmotors for our RepRap extruder motors, but they have a few problems (most notably being underpowered and having cheap plastic gears) so I decided to shop around and try to find a motor that I could be proud of. I stumbled onto the site kysanelectronics.com and ordered a bunch of their 12v DC gear motors. I got about 10 different motors with various gear ratios, sizes, etc. I decided to sacrifice one and take it apart. Turns out I was actually (miraculously?) able to piece it back together again, in working order too!
Here is a flickr set with the teardown.
Anyway, here are a few observations about these motors:
* they are all-metal construction (gears, housing, shafts, etc) the only plastic was an insulator on the terminals
* they are very powerful (my test is attaching vice grips and letting them rotate the vice grips, then trying to stop the rotating pliers with my hands. all could easily move the pliers, and most took a decent amount of force to stop)
* they are pretty cheap! for a single motor, they are $9.07 for a single unit and at volumes of 100+ they drop to $7.34. Not as cheap as the GM3, but they have dramatically higher strength, etc.
I think I may just have to place an order for a hundred of them. =)
Did you compare internals of gear motors with several different gear ratios? I’m curious as to whether they use different gears, or more stages of some “standardized” gear sets. For instance, can I buy a high gear ration motor like 38-023 and remove gears as appropriate for my app (changing the gear ratio on my own)? Or can I get enough gears from a high-ratio motor to make several lesser gear-ratio motors (using my own motors)?
Thats a good question. I did tear apart a few of the motors, but I didnt take pictures of them. I’m not sure, but the gears did look fairly standard. You might have a bit of trouble modifying the ratios, since alot of them have all the gears stacked up on one side of the gearbox.
Is it possible to insert a high-precision encoder on the input-side? By input side, I mean between the motor and the gear before reduction.
I would like to do this to increase the effective pulse/revolution output of the encoder without paying through the nose.
I would want to insert an encoder like this AMT11 from CUI, Inc:
https://www.mouser.com/datasheet/2/670/amt11-v-1308665.pdf