Complex Imaginary Test 3 Problem 26

[tabiolite]

In a 3-phase rectifier circuit, the silicon controlled rectifiers have firing angles of 0 degrees. If the incoming voltage waveform is v(t) = 460 sin(wt) where w= 377, what is the average voltage across the load.

The solution doesnt show the graph I would expect for the answer and the answer is 293V

which is simply the average of a half sine wave 460 x 2/ pi = 293 V.

I am thinking it should produce a graph of three identical sine waves out of phase by 120 degrees. Therefore to get the answer you need to do a seperate integral to get 0 to 60 degrees of the following phase which would produce a number greater than 293V.

I need someone to check me because I am not sure how the firing angles at zero get in to the question.

Maybe the problem is they meant to put single phase rectifier circuit because there is a pic of a single phase rectifier in the question.

 

[DK PE]

A text on power electronics (I used Wildi but others are fine) for a 3 Φ, full wave rectifier would give you:

Edc = {(3*√2)/π} Erms * cos α, sometimes approximated as Edc = 1.35 Erms * cos α , where α is the firing angle.

I don't have the Complex I. material so no clue how the team gets their answer. Have you looked for any errata from CI?