TransactionsPublished under the care of the General Secretary and the Treasurer . pulsion motion, when AS has the same signification asin that case and e,= ^2 V¥ASl,vX,^^_^^^_^^lO- volts. For the pair of brushes B2 B^ leading in the magnetizing currentep = o and 6r = ^2 VT ^S^ h V A^ ^^ ^ ^ _ g 10^ volts. where AS^ indicates the specific load of the armature from themagnetizing current. ARNOLD AND LA COUR: COMMUTATION, 865 Hence, for the pair of brushes B.^ B^, Ae= ~§^2 J2 ^^hv)^^—r-~ ^10-* volts. Thus, it is evident that the compensated motor is no morefavorable in the matter of commutation t
TransactionsPublished under the care of the General Secretary and the Treasurer . pulsion motion, when AS has the same signification asin that case and e,= ^2 V¥ASl,vX,^^_^^^_^^lO- volts. For the pair of brushes B2 B^ leading in the magnetizing currentep = o and 6r = ^2 VT ^S^ h V A^ ^^ ^ ^ _ g 10^ volts. where AS^ indicates the specific load of the armature from themagnetizing current. ARNOLD AND LA COUR: COMMUTATION, 865 Hence, for the pair of brushes B.^ B^, Ae= ~§^2 J2 ^^hv)^^—r-~ ^10-* volts. Thus, it is evident that the compensated motor is no morefavorable in the matter of commutation than the repulsion motorwith one pair of short-circuited brushes per pair of poles. Sincethe mean spark energy is proportional to the surface velocity vof the commutator, i ^ „^ may have a much greater value at thestart than at a greater speed. The repulsion motors and com-pensated motors work, therefore, at the start as satisfactorily asat greater velocities, though the coefficient of stray induction Sof the short-circuited coils is greater than in the true series Fig. 55. Statob and Rotor Windin^g ofCompensated Single-Phase Motoe. To discuss more exactly the dimensions of the alternating-cur-rent commutator motor, although this should be done mainly inreference to the commutation, would lead us too far. Hence, onlya few of the later commutators will be mentioned in the following: 19. Commutator for the Transformation of a PolyphaseCurrent into a Direct Current or into a Polyphase Cue-rent of Lower Frequency, According to the HeylandMethod. a). Commutator for synchronous machines. In order to make a polyphase machine self-exciting, or to com-pound it, the polyphase current must be converted into directVol. 1 — 55 866 ARNOLD AND LA COUR: COMMUTATION. current. This may be effected by means of a commutator. Sucha commutator as was proposed in 1903 by A. Heyland is repre-sented in Fig. 56. The magnetic winding GF of the generatoris divided into four parts, which are
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