4. In a single phase full wave converter (M - 2 connection), the rms transformer voltage is 300 V across each half of secondary. The PIV for each thyristor is
8. Two semiconverters are connected in series to form a single phase series converter. The input v = Vm sin ?t and a1 = a2 are the firing angles of the two converters. If a1 = a2 = 0, the dc output voltage is
9. In a 3 phase full wave regulator feeding a star connected resistance load the input voltage is 400 V line to line. The firing angle is 160°. The line to line output voltage would be
In a three-phase full wave regulator, output voltage is zero if a ? 150°.
10. A single phase semiconverter has a freewheeling diode. If the firing angle is a and the load is purely resistive, the periods of conduction and freewheeling respectively are