L298H board with Stepper motor Heat problem

Other Hardware Motors, Mechanics, Power and CNC
4

  1. The spec for your motor lists step angle as 7.5° so the steps per revolution should be 360/7.5=48, hence the code should be #define STEPS 48.

  2. Secondly, the coil resistance is 5.5 ohms/phase. You're driving it with 18V so the coil current will peak at 18/5.5=3.2 amps but the motor is only rated for surge current of 0.6amps, hence the overheading! The spec sheet applies if you're using a bipolar chopper driver which allows use of 24.0 V to overcome the effects of the winding inductance while limiting the surge current to 600ma (0.6amps). Since you're using a simple L298H motor driver you should reduce the drive voltage to 0.6A * 5.5V=3.3 VDC.

  3. With these new values in you code you may or may not be able to drive the motor at 100 RPM (stepper.setSpeed(100);). If you have problems at that setting try lower values to determine the max speed that you can drive it at.