From Stepper Motor power supplies, a deleted link-only answer contained some useful links,
Following on from Kossel 3D Printer, and the tutorial videos (see Kossel construction videos) the BuildA3DPrinter kit comes with an extruder stepper motor with a planetary gearbox. This results in a very high torque. However, as stated below, it has been replaced by the 3325_0, a motor with the same NEMA size and same torque.
I provided an answer on Stack Exchange 3D Printing site, to a question relating to an extruder stepper not operating correctly, Extruder stepper motor problem, what can be wrong?
I have replicated the question and answer below.
I found a stepper motor at the night market just off Pracha Songkro, for 10 baht Continue reading Mitsumi M49SP-3K
OK, so once I cleared my initial confusion between stepper motors and servos, I ended up having to look into stepper motors – as well as servos, which are covered in the servo expedition. They is also another blog on the different topic of geared d.c motors, so you may wish to check that out as well.