SIMAX3D 3PCS Nema 17 stepper motor 42x38mm 1.5A-3.8V 2 phase 4 wires 1.8 degrees with 39.3 inch cable for Creality CR-10 10S Ender 3 3D printer/CNC extruder and Y-axis

After upgrading my Ender 3 with a direct drive extruder upgrade I wanted to replace the massive and heavy stepper motor it came with with a much lighter one and so went looking and settled on the Simax3D in the 42-28 size, it looks good and is very light and unlike other steppers this one works with the existing printer wires and so just plug it in and it works and it was extruding smooth ( until the temps kick in ). However that is where the good ends, as others have pointed out it gets hot very hot and after about 7 min it was burning hot and was pushing 70c and increasing and i was not comfortable with that kind of temps on a stepper and like another pointed out at this temp it starts to not work right.However all is not lost and while deciding if i should return it I did some research and learned about the Vref on the Creality main board and this is definitely what is causing the high temps with the 42-28 and smaller steppers, by default the creality Extruder stepper is a 42-40 with a voltage of 1.20v to 1.38v and so the Vref on the creality board is set to output around 1.20v which is way to high for the 42-28 and smaller steppers, and so after research I adjusted the E Vref down to 1.0v by using a volt meter and using a small screw driver and turning it anti clockwise a tiny amount and ran a print test and it still got very hot, i kept doing this stepping it down bit by bit till i got to 0.85v where the motor gets to a comfortable warm but not hot or burninga and extrusion of the filament is working perfectly, I might play with the Vref and see if I can get it even lower without effecting extrusion to further reduce temps.In short if you are comfortable manually adjusting the Vref then these 42-28 are excellent and work well, but i can only give 4 stars for this reason also if it was 70c at 1.20v i would hate to see the temp at the rated 3.8v

Does exactly what is needs to on my creality ender 3 V1 Extruder

Used this stepper with my extruder but it gets very hot after a short period of use, so hot that you can burn yourself if you accidentally touch it 5 mins after starting a print. Seems to stop pushing filament through after a few layers probably due to the overheating.