Foree Bain's electric motor

Forée Bain's Electric Motor.

The illustration on this page represents the quadrupolar motor designed; and manufactured by Forée Bain of Chicago. The field and armature core are made entirely of wrought iron. The field is quadrupolar with like poles opposite. The novelty consists in the manner in which the armature is wound and connected, and also in the windings and connections of the field magnets. The armature contains eight coils, divided into two groups, the coils of each group being situated quadrilaterally with respect to each other. The current circulates in these groups alternately, and only at a point where the greatest effect is produced. The other group of coils are at this time passing the critical point of the field magnets, and should they remain active — as they would in a Gramme connection — they would partially act to retard the motion of the armature by their relation to the field; so they are cut out of circuit at this point, and their connections are so arranged with relation to one another that, in

order to prevent their discharge at the commutator and brushes, they are brought into circuit by themselves in such a manner that the current circulating in the two positive coils of the group is just neutralized or balanced by that in the two negative coils of the group. By this arrangement the idle portion of the armature is removed from circuit without being followed by disastrous results produced bysparking and flashing so common to open circuit motors or generators, and by this connection the internal resistance of the armature is one-fourth that of a bipolar Gramme machine, thus reducing internal work to a minimum, and increasing the efficiency to a maximum.

The manner of producing self regulation is the subject of a patent now pending, and can not be fully described. Suffice it to say that it is neither a shunt nor compound winding but it is done by a means attended with less loss than either of these methods. A motor of 5 horse power of this form, 40 amperes and 100 volts, can be put into a box eighteen inches square, and weighs only 260 pounds.