Exercise 1: Varying Resistive Load (without smoothing capacitor C=0)

Open Three-Phase Diode Bridge Rectifier panel, choose in menu Pre-Selected: Three Phase: Varying Resistive Load without smoothing capacitor.

Default Parameters

• AC Source Voltage : Ve= 120 V

• Frequency: 60 Hz

• R= 16.5 Ω

• For R = 16.5 ohms and Ve=120, measure the following values:

  • the maximum peak value of the output voltage

  • the minimum peak value of the output voltage

  • the average output voltage

• Compare these values with the calculated ones

• Set Ve to 120V and the frequency to 60 Hz, and complete the following table for many values of R

Table 10: Impact of Varying Resistive Load

• Justify the shape of the output voltage and output current.

• What is the effect of increasing the resistance value on THD?

• Deduce the role of the three-phase diode bridge rectifier and compare it with the single-phase diode bridge rectifier.

Exercise 2 - Varying Resistive Load (with smoothing capacitor)

In the panel, choose under Pre-Selected: Three Phase: Varying Resistive Load with smoothing capacitor.

Default Parameters

• AC Source Voltage : Ve= 120 V

• Frequency: 60 Hz

• R= 16.5 Ω

• C= 470 µF

Complete Tables 11, 12 and 13 for different values of the smoothing capacitor.

Case 1: C= 470 µF

Table 11: Case 1- Effect of varying Resistive Load With Smoothing Capacitor

Case 2 : C= 1100 µF