Computer science..

thyristors. Please note the numbering scheme, which is same as that used in a three-phase full-wave bridge converter or inverter, described in module 2 or 5. The thyristors are fired in sequence (Fig. 27.2), starting from 1 in ascending order, with the angle between the triggering of thyristors 1 & 2 being (one-sixth of the time period (60T) of a complete cycle). The line frequency is 50 Hz, with fT/1==20 ms. The thyristors are fired or triggered after a delay of a from the natural commutation point. The natural commutation point is the starting of a cycle with period, (6/60T=) of output voltage waveform, if six thyristors are replaced by diodes. Note that the output voltage is similar to phase-controlled waveform for a back are needed in each phase. The turning off of a thyristor occurs, if its current falls to zero. To turn the thyristor on, the anode voltage must be higher that the cathode voltage, and also, a triggering signal must be applied at its gate. Three-phase, Three-wire AC Regulator with Balanced Resistive Load The circuit of a three-phase, three-wire ac regulator (termed as ac to ac voltage converter) with balanced resistive (star- connected) load is shown in Fig. 27.1. It may be noted that the resistance connected in all three phases are equal. Two thyristors connected back to back are used per phase, thus needing a total of six Give task graphs and their communication times for one-to-all personalized communication of m-word messages on p nodes for the linear array and the mesh architectures