| 摘要 |
<p>A current control circuit inputs first to third continuous position detect signals that have a width of 120-degrees electric angle and that are not superposed in regard to time as well as fourth to sixth position detect signals that have a phase difference of 60 degrees from the above signals which are sent from position detectors that have three Hall elements to detect the position of the rotor. In response to the first to sixth position detect signals, the current control circuit cyclically energises the transistors (10a to 10d, 11a to 11d) of a bridge circuit that are related to an armature coils (4a to 4c) of each of the phases, such that the electric current flows through the armature coils of each of the phases in the positive and negative directions. When the position detect signals are interrupted. from being supplied to the corresponding armature coils, the magnetic energy stored in the coils is allowed to flow into the armature coils through which the current flows due to the next position detect signal. That is, the magnetic energy that is stored diminishes rapidly and the width of current before the armature current flowing into the coil rises is very narrowed, such that the torque does not decrease when the current is first supplied and that the counter torque is eliminated at the last stage of supply of current.</p> |
