Monocyclic System.—In this system, which is due to Steinmetz, the alternator is of a special type. In construction, there is a main single phase winding an auxiliary or teaser winding connected to the central point of the main winding in quadrature therewith.
The teaser coil generates a voltage equal to about 25 per cent. of that of the main coil so that the pressure between the terminals of the main coil and the free end of the teaser is the resultant of the pressure of the two coils.
Fig. 2,150.—Diagram of monocyclic system, showing lighting and power circuits.
By various transformer connections it is possible to obtain a practically correct three phase relationship so that polyphase motors may be employed.
In this system, two wires leading from the ends of the single phase winding in the alternator supply single phase current to the lighting load, a third wire connected to the end of the teaser being run to points where the polyphase motors are installed as shown in fig. 2,150.
The monocyclic system is described at length in the chapter on alternators, Guide No. 5, pages, 1,156 to 1,159.
Two Phase Systems.—A two phase circuit is equivalent to two single phase circuits. Either four or three wire may be employed in transmitting two phase current, and even in the latter instance the conditions are practically the same as for single phase transmission, excepting the unequal current distribution in the three wires. Fig. 2,151 shows a two phase four wire system.
