| 摘要 |
A stepping motor (M) with a self-inductance L is energized with pulses. If the motor current im is less than a reference value IR=Vref/Ro, the motor is connected to the battery and if im is greater than IR the motor is short-circuited. The motor current therefore fluctuates around the value IR. The motor current is adjusted so that the average voltage during a first measuring interval, in the range of the maximum angular velocity, is twice that during a second measuring interval at the end of the energizing phase. The two average voltages are compared with each other by measuring the time during which the switch (S) is in the energizing position. In this way it is not necessary to measure the voltage induced in the self-inductance L and every motor pulse is checked constantly. The motor current is adjusted at the end of the energizing phase to provide a correct adaptation to the required motor torque. Tolerances of all the elements involved, including the motor, are automatically compensated. |
