10.18 A three-phase half-wave converter in Figure P10.18 is operated from a three-phase Y-connected 208-V, 60-Hz supply and the load resistance is R === 1002. If it is required to obtain an average output voltage of 50% of the maximum possible output voltage, cal- culate (a) the delay angle a, (b) the rms and average output currents, (c) the average and rms thyristor currents, (d) the rectification efficiency, (e) the TUF, and (f) the input PF.