To provide a 3-phase pulse motor which can avoid position discrepancy regardless of a phase by which stepping is practiced by taking arrangement relations of poles of respective phases into consideration.
A comb-shaped slider 13 is movably provided so as to face a scale 11 on which teeth are formed with constant pitches. The pole and coil of a U-phase are divided into two to form a 1st U-phase pole 13U1 and a 2nd U-phase pole 13U2 which are provided on both the sides of the slider 13. The two divided coils are connected in series to each other. Voltages whose phases are successively shifted by respective electric angles of 2 π/3 radians are applied to the coils of the respective poles. When the maximum voltage is applied to the U-phase coils 15U1 and 15U2, currents with polarities shown in the figure are made to flow through the respective coils and fluxes are formed between the respective poles in magnetic routes shown in the figure. The magnetic route between the V-phase and U-phase and the magnetic route between the W-phase and U-phase, therefore, have same lengths and the phase of the propulsive vector of the U-phase itself and the phase of the resultant propulsive vector of the V-phase and W-phase which contribute to the U-phase agree with each other, so that position discrepancy can be avoided.
MAEDA YUTAKA
MURAGUCHI YOSUKE
NARUHISA MASAAKI
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