Ques. How may the rotation of a motor be reversed?
Ans. By reversing either the current through the fields, or the current through the armature.
Ques. What will happen if both currents be reversed?
Ans. The motor will run in the same direction as before.
Fig. 401.—Fairbanks-Morse wire wound armature coils. These coils are form wound and are thoroughly insulated and baked before assembling in the slots. Material of great mechanical strength as well as high insulating value is used, and the coils are subjected to dippings in insulating compound and to bakings, thus driving out all moisture and making a coil which is practically waterproof and which will withstand rough handling. These coils, when completed, are placed in the slots, where they are retained by bands on the three smaller sizes and by hardwood wedges on the larger sizes.
Ques. What is the effect of supplying current to a series dynamo?
Ans. It will run in a direction opposite to its motion as a dynamo.
Ques. What is the result of reversing the direction of current at the terminals of a series motor?
Ans. It will not change its direction of rotation, since the current still flows through the armature in the same direction as through the field.