PURPOSE:To increase speed and torque, by employing a horizontal U-shaped core as the magnetic pole of an armature, then mounting an exciting coil with both foot sections thereof being employed as magnetic poles and closing flux of the magnetic poles by means of two salient poles facing each other. CONSTITUTION:A rotary shaft 1 is supported rotatably by bearings in housing, and a rotor 2 is secured. The rotor 2 is provided with fourteen salient poles with same width and pitch. A fixed armature 3 is provided with magnetic poles 4a- projecting to the inside of annular sections 3a- where the widths of respective magnetic poles 4a-4b are equal to the width between salient poles 2a-2b, and the magnetic poles 4a- are formed while separated each other by same width. The circular sections 3a- are provided with curved recesses 8a-8f. Voids 10a-10f are cut from the armature 3 to split the annular section into six sections, and respective splitted sections are employed as horizontal U-shaped cores with both foot sections thereof being employing as magnetic poles. Exciting coils 5a- are mounted on the magnetic poles 4a-. Consequently, flux is closed by the salient poles 2a-2b and no flux is leaked.