Ans. No.
Alternating current windings are usually different from those used for direct currents. One distinction is the fact that a simple open coil winding may be, and often is, employed, but the chief difference is the intermittent action of the inductors.
In a direct current Gramme ring winding a certain number of coils are always active, while those in the space between the pole pieces are not generating. In this way a practically steady pressure is produced by a large fraction of the coils.
In the case of an alternator all of the coils are either active or inactive at one time. Hence, the winding need cover only as much of the armature as is covered by the pole pieces.
Fig. 1,391.—Engberg alternating current generating set; shown also in cross section in fig. 1,387. The set comprises a vertical engine and alternator, direct connected and placed on one base. The lubrication system comprises an oil pump situated in the base of the engine, pumping the oil from an oil reservoir up into a sight feed oil cup which leads to a distributing oil trough on the inside of the engine frame, from here oil pipes lead to all movable bearings, which are grooved to insure proper distribution of oil. The oil is drained from bearings into the base, filtered and re-pumped. A water shed partition is provided in the engine frame, preventing any water passing from the cylinder down into the engine base and mixing with the oil, consequently leaving good, clean oil in the oil reservoir at all times. The details of the lubrication system are shown in fig. 1,387.
Revolving Field Alternators.—In generating an electric current by causing an inductor to cut magnetic lines, it makes no difference whether the cutting of the magnetic lines is effected by moving an inductor across a magnetic field or moving the magnetic field across the inductor.
Fig. 1,392.—Allis-Chalmers revolving field self-contained belted type alternator.