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A 3-phase bridge converter is given a three-phase supply in the phase sequence R-Y-B. Let the neutral to R phase voltage be Vm sinωt. The first SCR (connected to R phase) is fired at an angle of 15°. What is the maximum value at the output terminals at this instant?

Correct Answer: 1.5 Vm
In case of a 3 phase bridge converter, the maximum value of voltage at the output terminal is always 1.5 Vm.

A voltage source Vs = Vm sinωt is connected in series with a resistance R and an SCR. At some firing angle delay of α a positive gate pulse is applied to the SCR which turns on the SCR. Considering ideal conditions, at the instant α the voltage at the resistor terminals Vo

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A cow was standing on a bridge, 5m away from the middle of the bridge. A train was coming towards the bridge from the ends nearest to the cow. Seeing this cow ran towards the the train and managed to escape when the train was 2m away from bridge. If it had run in the opposite direction, it would hit by the train 2m before the end of the bridge. What is the lenght of the bridge in meters assuming the speed of the train is 4 times that of cow ?

A semi-converter circuit gives the following voltage waveform. Find the expression for the average output voltage with Vs = Vm sinωt and firing angle α