| 摘要 |
PURPOSE:To obtain such a universal motor as is ready for variably setting a rotational speed covering a wide range by controlling a current flowing to each element of armature coils according to magnetized polarity and rotary position of a rotor yoke magnetized by a field coil. CONSTITUTION:Upon closing an AC power supply E, a field coil 8 of a motor M is AC-excited, and rotor yokes 6a, 6b are magnetized synchronously with a period of an alternating field according to the alternating field coping wity a power frequency generated on a field yoke 7. Then, magnetism-induced elements 14a-14c are induced correspondingly to a position of the rotor yoke 6a, detection circuits 21a-21c in polarity signal forming circuits 27a-27c output a sine wave form signal, and the signal is amplified on amplifiers 22a-22c. Polarity decision comparison circuits 23a-23c turn ON driving transistors 24a-24c on a low-level signal from the amplifiers 22a-22c and also turn ON driving transistors 25a-25c on a high-level signal, and a current is carried to armature coils 10a-10c according to the transistors which are kept ON, thus actuating the motor M. |
