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Max stepper motor current

Posted by witor 
Max stepper motor current
May 01, 2020 03:38PM
I have replaced my Anet A6 board with SKR1.3 and LV8729 extruder driver. Everything works great but my extruder struggles a bit tu push fillament and ocasionally skips steps. I have set current to about 0.8A. Extruder motor is not even getting worm. I can't find Anet A6 stepper specification, but I have found specks (below) for A8 (pre A6 model). It looks like motor could possibly witstand way more current and have much more torque.

Can I safely slowly (litle by little) increase the current to about 1.2-1.3A provided that the motor stays no more than warm? LV8729 has a max current of 1.6A. Should I look for a different driver capable of providing more current?

The SL42STH40-1684A motor specs are:

Step Angle: 1.8°
Step Angle Accuracy: ±5 % (full step, no load)
Voltage: 2.8 V
Current per phase: 1.68 A
Resistance per phase: 1.65 Ω
Resistance accuracy: ±10 %
Inductance per phase: 3.2 mH
Inductance accuracy: ±20 %
Holding torque: 3.6 kg·cm (0.4 N·m)
Moment of inertia: 54 g/cm^2
Weight: 0.28 kg
Orientation torque: 150 g/cm
Length: 40 mm
Temperature rise: 80 °C max (rated current, 2 phases on)
Re: Max stepper motor current
May 04, 2020 01:31PM
There are two different motors that could come with an A8 - the specs you show are for the motors provided with older A8s - newer A8s have motors that only handle about 0.9A. So you should proceed with caution. However, if the motor isn't getting warm then there should be no problem. I ran my A8 X and Y motors at up to 60C regularly before I replaced them with better ones.
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