1) A three-phase half wave controlled rectifier is operated with a 17kVA, 460V Y connected transformer. If the load resistance is 10 2, a) Calculate the firing angle required to obtain 75% of maximum possible de voltage. b) Average current and RMS current(use basic definition and integration for RMS value) c) Average and RMS current of the SCR.

a) Explain the operation of the controlled full-wave bridge rectifier shown in figure 3. b) The controlled full-wave bridge rectifier shown in figure 3 has a source 120 V rms at 60 Hz, R = 1092, L=20 mH, and a = 60°. Determine: i. An expression for the load current. ii. The average load current. iii. The power absorbed by the load. iv. Sketch the graph of the output waveform. Vs S₁ S4 Figure $3 $₂ Lo Vo

Three Phase Full-Wave Fully Controlled Rectifier when highly Inductive load is connected: i. Draw graphs when α = 30, 60, 90, 120, 150 degrees. ii. Derive the output average voltage. iii. Derive the output rms voltage.

4- Single phase centre-tape rectifier with 100V peak secondary voltage per coil, energizing 10 Ohms and 2mH inductance with 50Hz source. The output rectified voltage drops to ...of the Vdc. *

B. A single-phase fully controlled, full-wave, bridge rectifier has a source of 230 V rms at 50 Hz, and is feeding a load R=25 and L - 10 mH. The firing angle a= 45° and the current extinction angle B-230". It is required to: (a) Sketch the appropriate load voltage and load current waveforms. (b) Determine whether the current is continuous or discontinuous. (c) Determine the average load voltage and current. (d) Determine the rms load voltage and current. (e) Determine the efficiency of the converter

Question 1 a) Compare the holding current with the latching in SCR. b) A 400 V/50 Hz three-phase system is loaded with an ideal three-phase diode rectifier having a completely smooth output current of 50 A. An ideal three-phase thyristor converter is connected in parallel with the diode rectifier. The output current of the thyristor converter is also 50 A and completely smooth, but the output power of the thyristor converter is zero. i. Draw the waveforms of the input currents to the two converters and the the sum of the two currents. ii. Calculate the power factor for the total load. c) The shown converter in Figure 1 operates in continuous conduction mode. Assume the components are ideal. i, (1) in (t) v ic (t) Vo (t) iL (t) +v (t) - is (1) "; (1) Figure 1 i. Sketch of i (t) and VL(t) for one switching period Ts. ii. Determine the DC voltage gain Vo/Vg as function of duty cycle, D.

Q-2: A singie phase fiull-wave controlled rectifier is connected to RL load (R-15 ohm and 1.-20mH ). Vs- 240 and 50 Hz supply When the firing angle is a=55. Deternine: A} the average voltage and average current in the load. B) The form factor and ripple factor. C) Peak inverse voltage of the thyristor.

Question 3) An ohmic loaded half-wave controlled rectifier given in the figure below feeds a 25 Q load and the peak value of the source voltage is 350V and its frequency is 50 Hz. Accordingly, find the following desired circuit parameters: a) Effective (rms) voltage of the source, b) the peak current of the load, c) Average stress of the load, d) Average current of the load, e) The effective (rms) voltage of the load, f) Effective (rms) current of the load, g) Power of the load K R

1) a) As depicted in the figure, input voltage is 120 Volts (RMS) and diode drops are 0.7 Volts. Design this circuit with given two ac outputs and calculate turns ratio of live transformer. voltage i) 10 V ii) 100 V 2) b) Consider a circuit using Si diodes and 10 k ohms resistors. Design this clipper circuit with output ranges below; i) -0.7 V and above ii) +2.1 V and above iii) +1.4 V c) As given in the figure a clamper circuit with the input +10V- signal Vi is proposed to design. Determine the output voltage with the exact solution step by step. Sketch transfer characteristic Vo versus V₁. V₂ Vo H 2RS -10V- -2√ 01 Vo Trims

A three phase full wave rectifier is shown below along with the peak input phase voltage Vm=169.7V. The load is purely resistive. The rectifier delivers Ipc = 100 A and the source frequency is 60 Hz. The DC output voltage is Vpc=280.7V and. The RMS transformer secondary current is equal to 81.72A, the output RMS voltage is equal to VRMS=280.93V and the output resistance is equal to 2.8070. The TUF would be equal to: Secondary a平a字a辛 R 太D。太D。太D. Select one: 0.875 Ob. 0.955 O C. 0.551 O d. 0.432 Compared with power transistors, thyristors have the following characteristic