Prusa-Firmware/Firmware/variants
Marek Bel e82ba78768 Scale extruder motor current linearly with speed.
49% less heating when running at low speed and standstill, 4% more torque at maximum extrusion rate (15mm^3/s), 15% more torque in high speed movements (un/retractions).

StealthChop mode is used for low speeds (below 900mm/min)
spreadCycle is used above. Transition speed is well above maximum extrusion rate of 15mm^3/s (275mm/min) so mode transition is not expected to be visible on printed surface.

StealthChop is expected to improve printed surface quality (less artifacts).

Warning you can burn extruder motor if it is not the same impedance as original Prusa i3 Extruder stepper motor. There is no current feedback in low speed so lower impedance motor can be burned by over current.

Even there is no direct current feedback, there is no risk for original motor thermal runaway, as motor resistance increases with temperature, current decreases.

Standstill peak phase current is expected to be 500 mA and linearly increase with speed to 970 mA at 900mm/min where spreadCycle constant current regulation takes over and keeps peak current at 805 mA to maximum speed possible.

As motor heating increases with current squared, lowering low speed current from 700mA to 500mA decreases heating 49% in thate mode, where motor spends most of the time.
2021-03-17 12:39:15 +01:00
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1_75mm_MK2-RAMBo10a-E3Dv6full.h Add DEFAULT_TRAVEL_ACCELERATION in all variants 2021-02-03 11:20:28 +01:00
1_75mm_MK2-RAMBo13a-E3Dv6full.h Add DEFAULT_TRAVEL_ACCELERATION in all variants 2021-02-03 11:20:28 +01:00
1_75mm_MK3-EINSy10a-E3Dv6full.h Scale extruder motor current linearly with speed. 2021-03-17 12:39:15 +01:00
1_75mm_MK3S-EINSy10a-E3Dv6full.h Scale extruder motor current linearly with speed. 2021-03-17 12:39:15 +01:00
1_75mm_MK25-RAMBo10a-E3Dv6full.h Add DEFAULT_TRAVEL_ACCELERATION in all variants 2021-02-03 11:20:28 +01:00
1_75mm_MK25-RAMBo13a-E3Dv6full.h Add DEFAULT_TRAVEL_ACCELERATION in all variants 2021-02-03 11:20:28 +01:00
1_75mm_MK25S-RAMBo10a-E3Dv6full.h Add DEFAULT_TRAVEL_ACCELERATION in all variants 2021-02-03 11:20:28 +01:00
1_75mm_MK25S-RAMBo13a-E3Dv6full.h Add DEFAULT_TRAVEL_ACCELERATION in all variants 2021-02-03 11:20:28 +01:00