The stepper motor assistant

B2 Spice can be used to display the operating point of a stepper driver circuit. It can also be used to perform parameter sweeps in order to see the correct voltage or current limiting resistor values for L-R drive circuits. The circuit below uses data from the Sonceboz 6600-20-25 Stepper Motor. Four timed switches are used to realise a half phase full step sequence. The darlington transistors sink current from the motor coil windings during each phase excitation.

Stepper Motor Circuit (Download: A/D 2000 | A/D v4)
B2 Spice A/D v4's new dynamic schematic feature shows the
current flow during the first phase excitation.

Stepper Motor Graph (plot overlay has been unchecked). Click HERE to display the overlayed plot. Note: No attempt has been made to model the motors magnetic characteristics in this simuation.

Switches V(n1...n4) show the coil firing sequence. i(vam1..4) displays the current in each phase of the motor.