I'm designing a board that has to control several DC brushed motors. The motors are SY54E-DC24V-2PCE. I didn't find a datasheet but some references like this and this.

I measured the DC resistance of the windings and it is 3.9 ohm. Powering up the motor with 24VDC, without any load, it draws about 350 mA.

I bought some dev boards to test the drivers before selecting them for my custom board. On my desk I have:

DRV8256 is rated for 2.5A and after playing with all the settings the motor barely spins but with a very rough and irregular motion.

DRV8871 is rated for 3.6A (I disabled the current control) but the motor never spins.

L293D is rated for 1.2A only (even the datasheet describe it as "high-current" driver) but it is the only one driver that can run the motor, though with a very loud noise (right now I'm using a 500 Hz PWM).

I really cannot use a large PDIP ICs on my board so I want to understand why the other drivers are not able to control the motor. And anyway the L293(D) has a current too low to drive the motor under load.

I understand you don't have the crystal ball, but do you have any idea about these behaviors? And if I should go deeper and try to get the other drivers to work, or it would be better to select another kind of driver...


Here the current profile at power up, with the following settings:

  • calibrated power supply 24.0 V (capable of more than 6A)
  • shunt resistor of 10.1 ohm (measured)
  • motor connected using 20 cm thick wires

enter image description here

As you can see from the cursors, the steady-state current is about 218 mA, while the initial peak is about 1.44 A well below the current rating of the tested drivers.

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    \$\begingroup\$ I understand you don't have the crystal ball - you understand correctly. A minimum you could do is to post your schematics. \$\endgroup\$ – Eugene Sh. Feb 23 at 14:31
  • \$\begingroup\$ Sorry, which schematics? I said I'm using the dev boards I linked. \$\endgroup\$ – Mark Feb 23 at 14:36
  • \$\begingroup\$ Ok, I see. Sorry, jumped right to the drivers datasheets \$\endgroup\$ – Eugene Sh. Feb 23 at 14:37
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    \$\begingroup\$ Still, you should show how you configure and power the boards. Better focus on one \$\endgroup\$ – Eugene Sh. Feb 23 at 14:39
  • \$\begingroup\$ For DRV8871 I said it: I disabled the current control. No other settings. L293D shield has no settings. DRV8256PEVM I tried all (literally) the combinations the GUI allows. I also described the operating conditions: power supply voltage, PWM frequency, motor. If you need a specific detail, please ask and I will answer. \$\endgroup\$ – Mark Feb 23 at 14:41

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