Mimal9999 wrote: ..... somehow I felt like resuming the project, but I don't want to keep playing with those drivers that I think are extremely resistant, so I decided to buy something else. I was thinking about drv8825, I heard that they are much better than described above. Is this a good choice? Can he buy something else?
Choosing to buy the 'better' ones is just as good as the ones you already have.
Whatever you buy, following the same procedure as before, they will all be 'resistant' (!)
DRV8825 have not much advantage over A4988; they have a wider range of microstepping and give the possibility of a slightly higher load current. None of these assets have significant application in your requirements ...
You do not need 1/32 microstepping, and setting the maximum current for your motor freely falls within the A4988 range (even without using additional forced cooling of the driver board).
The important parameters for your engine [Model: KS42STH40-1204A) are:
o Standard Voltage: 3.6V
o
Phase current: 1.2A o Phase resistance: 3 ohm
The rest doesn't mean much at the moment.
If you start anything, you first need to set / (adjust the potentiometer) the maximum current for the motor, which is initially and theoretically 1.2A
From your relationship it follows that the control will be full-step, so this current can be reduced to 71% of full load (see post above). At this resultant A4988 current will feel 'free' ...
If the symptom of the engine's operation is its slowness, then the reasons should be sought in its control (Program), and the motor voltage level too low.
The characteristic 'squeaking' of the engine is a symptom of lost steps and 'breaking' of synchronization.
Note the three parameters presented above and their close relationship under Ohm's Law.
The motor supply voltage has no direct effect on its rotational speed, which is the result of the frequency of pulsing steps, but a higher voltage accelerates the 'jump' by another step, so it is possible to increase the frequency of their pulsing, which results in 'clean' (without losing steps) increased RPM turnover.
The actual motor supply voltage from the power supply should be several times higher than what the datasheet gives as'
Standard Voltage '. There are applications that are even 30x higher.
The limitation here may be the type / type of the chip of the driver board itself.
DRV 8825 allows power supply up to 45V; while A4988 only allows 35V.
Considering your poor enthusiasm in this direction, my time is certainly meaninglessly lost here ...
e marcus