초록 ▼

A device for detecting asynchronization or stepping out of a stepping motor without making the stepping motor large in size. Parallel resonance circuit LC is provided in a recovery circuit of stator coil RL of the stepping motor for detecting linking current IX. If the stepping motor is out of step,

A device for detecting asynchronization or stepping out of a stepping motor without making the stepping motor large in size. Parallel resonance circuit LC is provided in a recovery circuit of stator coil RL of the stepping motor for detecting linking current IX. If the stepping motor is out of step, the magnetic resistance between stator and rotor increases while the reactance of stator coil RL decreases. When motor drive current ID is turned off, a large transient current is momentarily generated yet is quickly dampened. While the motor drive current ID is off, linking current IX approaches zero. Consequently, if the stepping motor is out of step, there is no substantial difference in the linking current IX when motor drive current ID is turned on from when motor drive current ID was off. Also, the amplitude of the transient or resonance waveform is smaller than the amplitude when the stepping motor is operating normally. By thus detecting the resonance waveform of the parallel resonance circuit when motor drive current ID is turned on, it can be precisely determined whether or not the stepping motor is out of step.

대표청구항 ▼

A device for detecting step-out of a stepping motor having a stator coil comprising: detecting means for detecting at least one of current and voltage of a recovery circuit, said recovery circuit being connected in parallel with the stator coil, said recovery circuit exhibiting signals indicative of

A device for detecting step-out of a stepping motor having a stator coil comprising: detecting means for detecting at least one of current and voltage of a recovery circuit, said recovery circuit being connected in parallel with the stator coil, said recovery circuit exhibiting signals indicative of switching transient of said stator coil, said signal indicative of switching transient being indicative of a step-out condition; and determining means for comparing said at least one of detected current and voltage signals indicative of said switching transient to a corresponding one of a reference current and voltage; said recovery circuit comprising an LC parallel resonance circuit.