29-10-2010, 01:29 PM
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FOUR-QUADRANT CHOPPER DRIVE FOR UNIVERSAL DC MOTOR
#G-5, Ratna Complex, Ameerpet,
#310, OPP. Kalaniketan, Dilshukh Nagar
AIM:
The main aim of the project is to develop a speed control system for DC motor using four-quadrant chopper. Using four-quadrant chopper it is possible to demonstrate forward &reverse motoring and braking.
PURPOSE:
The purpose of the project is to implement a simple and cost effective process to control the speed of DC motors using the most popular technique four-quadrant chopper method.
DESCRIPTION:
In this project armature is excited by a variable dc supply obtained from four-quadrant chopper. The system is provided with various control keys, such as START, STOP, REVERSE MOTORING, REVERSE BRAKE, FORWARD MOTORING, FORWARD BRAKE, INCREMENT and DECREMENT. Using these keys, the user can set the motor to run in any one of the following modes, namely Forward motoring, Reverse motoring, Forward braking and reverse braking. The speed can be varied by varying the voltage given to the PWM converter (using keypad).
Moreover, the system is provided with Soft start facility i.e., starting the motor without allowing the armature current to exceed the full load current. The Hardware of this system includes uncontrolled rectifier using diodes, chopper using IGBT’S, control keys, speed adjust potentiometer and other logical circuits.