83

INVENTIONS OF NIKOLA TESLA.

The con veil tioi ml figure of a motor here introduced, Fig. 67,will give an idea of the solution furnished by Mr. Tesla for thespecific problem, deferring to the drawing, a is the field-mag-net, b the armature, c the field coils, and d the armature-coils ofthe motor.

Generally speaking, if the mass of the cores of armature andfield be equal, the amount of copper or ampere turns of theenergizing coils on both should also be equal; but these condi-tions will be modified in different forms of machine. It will beunderstood that these results are most advantageous when exist-ing under the conditions presented where the motor is runningwith its normal load, a point to be well borne in mind.