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I purchased two DQ542MA drivers in order to run two NEMA 17 steppers. After about five days of use I noticed that the green indicator light had gone out on both drivers.

The DQ542MA driver running my NEMA 23 High Torque stepper was still running and it has been connected to that stepper for five months now. Using an Ohm meter to check I found that the 10amp 125v LittleFuse connected to the power pins had blown on both drivers connected to the NEMA 17 steppers cutting off the power.

I decided to test the still working driver by disconnecting it from the NEMA 23 stepper and corresponding pins on the motherboard and connecting and resetting it to work with one of the NEMA 17 steppers. The minute I turned my printer back on, the still working stepper (now attached to the NEMA 17 stepper) immediately blew the same fuse. I don't understand why the NEMA 17 steppers blew the fuses of the drivers, seeing as how both are properly set to a RMS of 1.69 and a pulse/rev of 400, and both are connected to a 24v PSU.

My question is: "When I fix the drivers should I solder in a 15amp 125v LittleFuse to better help the power flow and prevent any further blown fuses?"

1 Answer 1

If the fuse blows - there is a reason for that, so changing it for a higher rating without understanding the source of the problem is:

Asking for fire!!!

Every stepper has its own internal resistance (and as we have a magnetic field it is called a reluctance), that is limiting the max current, but this equation needs to take U given to the motor.

A simple and popular solution is to give only as much voltage as needed, utilizing the resistance (RL) of the winding to limit the current (fig. 4a). A more complicated but also more efficient and precise solution is the inclusion of a current generator (fig. 4b), to achieve independence from the winding resistance. The supply voltage in Fig. 4b has to be higher than the one in Fig. 4a. A comparison between both circuits in the dynamic load/working order shows visible differences.

Source Stepper motor driving by H. SAX - page 2

That said - the higher voltage applied to the stepper - the higher current is flowing via its coils.

Please check the datasheet of your driver to see how it is managing to current limit your stepper as that looks like a source of your issue.