Question

In single phase RLE load, calculate the voltage across the thyristor when current decays to zero using the data: (Vs)r.m.s=220 V, f=40 Hz, R=1 Ω, E=90 V, β=230°.

(a) -328.33 V

(b) -325.48 V

(c) -254.85 V

(d) -284.48 V

This question was addressed to me in unit test.

This interesting question is from Solid State Controlled Drives topic in chapter Introduction to Solid State Controlled Drives of Electric Drives

Answer 1

Right answer is (a) -328.33 V

To explain I would say: In single phase RLE load the voltage across the thyristor when current decays to zero VT=Vmsin(β)-E=220×√2sin(230°)-90=-328.33 V.