SYNCHRONOUS RECITFIER

23S

inductance, with open-circuit rectification, by shifting the brushes
so that the brushes open the circuit only at the moment when
the (inductive) current has reached zero value or nearly so, as

FIG. 83.—Voltage waves of open-circuit rectifier with shifted brushes.

shown in Figs. 83 and 84. In this case, the brush maintains con-
tact until the voltage, e, has not only gone to zero, but reversed
sufficiently to stop the current, and the rectified voltage then is
shown by e0 in Fig. 83, the current by i and i0 in Fig. 84.

FIG. 84.—Current waves of open-circuit rectifier with shifted brushes.
140. With short-circuit commutation the voltage waves are as
shown by e and e$ in Fig. 85. With a non-inductive supply and
non-inductive receiving circuit, the currents would b$ as shown
by i and i0 in Fig. 86. That is, during the period of short-circuit,