The objective of this study is to familiarize with the SCR in controlled rectification with resistive and inductive load.

Included in this paper is a list of the apparatus required and the theory behind the single-phase full-wave controlled rectifier using R-load and as well as the single-phase bridge rectifier and the single-phase full-wave controlled rectifier using RL-load. An example of a table for recording observations is given as well as pictures and formulas making backgroud information clearer.

Excerpt

#LAB 2

STUDY OF SINGLE PHASE FULL WAVE CONTROLLED RECTIFIER USING R - LOAD AND RL - LOAD

OBJECTIVE

To familiarize with the SCR in controlled rectification with resistive (R) and inductive

(L) load.

APPRATUS REQUIRED

1. Thyristor Kit

2. Connecting Wires

3. Oscilloscope

4. Multi-meter

THEORY

Single-Phase Full-Wave Controlled Rectifier using R - load Single-Phase Bridge Rectifier

Figure 1(a)shows a fully controlled bridge rectifier, which uses four thyristors and a

resistive load and also the resulting voltage and current waveforms are shown infigure 1(b).

During the positive half cycle of source voltage, thyristors T1 and T2 are in forward blocking mode and T3 and T4 are in reverse blocking mode. The thyristor does not conduct until they are triggered. When thyristors T1 and T2 are triggered at [illustration not visible in this excerpt] and [illustration not visible in this excerpt] go in forward conduction mode and thus starts conducting upto ωt = π. The output voltage appears for the period of [illustration not visible in this excerpt] and T2 goes turned off by natural commutation.

During the negative half cycle of source voltage, thyristors T1 and T2 are in reverse blocking mode and T3 and T4 are in forward blocking mode. The thyristors does not conduct until they are triggered. When thyristors T3 and T4 are triggered at [illustration not visible in this excerpt]

and T4 go in forward conduction mode and thus starts conducting upto [illustration not visible in this excerpt] The output voltage appears for the period of [illustration not visible in this excerpt].

The average value of load voltage (output voltage) is given by,