This is the design drawing of the bracket for mounting a NEMA 11 geared stepper motor on a GP equatorial mount. It can be used as a motor unit to implement OnStep on a GP equatorial mount.
Drive.mp4
- NEMA11 Stepper Motor with 20:1 Planetary Gearbox (28HS2806A4XG 28XGJ-20)
- KYOIKU GEARS S75B40B+0306 (Module0.75 40teeth 30mm shaft6mm)
- GP Motor Base : These can be cut out from 5mm thick aluminum plate. (STL)
- NEMA11 Geared Bracket : 3D Printed Parts (STL)
- GP Motor Cover : 3D Printed Parts (STL)
When a NEMA 11 stepper motor with a gear ratio of 1:20 was driven by 12V, it was possible to introduce 480x speed. (OnStep MiniPCB V1 DRV8825 Teensy4) However, this may depend on the condition of the equatorial mount.
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![]() Autoguiding with PHD2 |