The addition of still another diode-capacitor section to a Voltage trippler, as shown in Below Figure, produces an output four times the peak secondary voltage. C4 charges to 2Vp through D4 on a negative half-cycle. The 4Vp output is taken across C2 and C4, as shown. In both the tripler and quadrupler circuits, the PIV of each diode is 2Vp.
Why Damper windings used in synchronous motors
Synchronous motors are not self starting machines. These machines are made self starting by providing a special winding in the rotor poles, known as damper ...