Abstract: A motor includes a stator, a first rotor and a second rotor. The stator has a plurality of outer teeth projecting outward from an annular stator yoke, a plurality of inner teeth projecting inward from the stator yoke, and windings wound on both of the teeth. Instead of providing both of the teeth with the windings, toroidal windings can be wound on the stator yoke at each section sandwiched between the slots, which stator yoke is disposed between each one of the inner slots and corresponding each one of the outer slots. This motor is structured such that the phases of cogging torque and torque ripple existing between the stator and the second rotor can be reversed with respect to the phases of cogging torque and torque ripple existing between the stator and the first rotor.

Abstract: Disclosed are a papermaking method comprising the steps of sheet-formation of an aqueous papermaking stock which contains a cellulose fiber or the said fiber and an inorganic filler, dewatering and drying, characterized by the addition of a starch ether derivative of a general formula (I): ##STR1## where St-O represents a starch molecule residue, R.sub.1, R.sub.2 and R.sub.3 independently represent an alkyl group having from 1 to 18 carbon atoms or a benzyl group, provided that two or more of these R.sub.1, R.sub.2 and R.sub.3 must not be a benzyl group or an alkyl group having from 5 to 18 carbon atoms at the same time, and any two of these R.sub.1, R.sub.2 and R.sub.3 may be bonded to form a cyclic structure, the said derivative containing the ether bond preferably in a degree of substitution of from 0.01 to 0.1, to the said papermaking stock in an amount of from 0.05 to 5.