Questions 1 to 3 relate to a three-phase SCR rectifier supplied from a 415 Vrms, 50 Hz ac source. For a 100 Ω resistive load, determine the peak, minimum and average load current for SCR firing angle...
Questions 1 to 3 relate to a three-phase SCR rectifier supplied from a 415 Vrms, 50 Hz ac source. For a 100 Ω resistive load, determine the peak, minimum and average load current for SCR firing angles of: (a) a-0° (5.87 A, 5.08 A, 5.6 A) (b) α = 45° (5.67 A, 1.52 A, 3.96 A) (c) α-70° (4.5 A, 0 A, 2.0 A) How will your answers change if a very large inductance (zero resistance) is added in series with the load resistor. (5.6 Α, 3.96 A, 1.916 A) For a70° in problem 1 above, determine the load inductance required to just achieve continuous conduction. (56 mH) Hence or otherwise for this load inductance, develop time varying expressions for the load current for any firing angle, both in continuous and discontinuous conduction Answer 2. ot 415V2 t) costa)t-10.14) + Ae 0.179 101.6 78coS(-40142, (α > 70°) where A e 0.179 Determine the maximum source inductance permissible for this rectifier if the droop in dc output voltage at a full load current of 20 A must be less than 5% of the maximum possible dc output voltage. (4.67 mH) Plot the dc output voltage as a function of load current for the SCR firing angles of question 2 above 3.
Questions 1 to 3 relate to a three-phase SCR rectifier supplied from a 415 Vrms, 50 Hz ac source. For a 100 Ω resistive load, determine the peak, minimum and average load current for SCR firing angles of: (a) a-0° (5.87 A, 5.08 A, 5.6 A) (b) α = 45° (5.67 A, 1.52 A, 3.96 A) (c) α-70° (4.5 A, 0 A, 2.0 A) How will your answers change if a very large inductance (zero resistance) is added in series with the load resistor. (5.6 Α, 3.96 A, 1.916 A) For a70° in problem 1 above, determine the load inductance required to just achieve continuous conduction. (56 mH) Hence or otherwise for this load inductance, develop time varying expressions for the load current for any firing angle, both in continuous and discontinuous conduction Answer 2. ot 415V2 t) costa)t-10.14) + Ae 0.179 101.6 78coS(-40142, (α > 70°) where A e 0.179 Determine the maximum source inductance permissible for this rectifier if the droop in dc output voltage at a full load current of 20 A must be less than 5% of the maximum possible dc output voltage. (4.67 mH) Plot the dc output voltage as a function of load current for the SCR firing angles of question 2 above 3.