Computer Based Speed Control Application for Universal Motor

In this study, speed control of alternative current (AC) universal motor is made in a computerized manner using PIC16F84A and PIC18F2550. AC universal motor speed control is realized by triggering the motor power circuit, triac with the phase angle control method by programming PIC16F84A. In the phase angle control method zero crossing points of AC line signal are detected by zero crossing detector and applied to the analog input of PIC16F84A. Zero crossing information applied to the microcontroller has provided phase control at a desired angle value in each alternance of the line. Motor speed control commands via computer are made by means of the control panel designed under Visual Basic 6.0 platform by using PIC18F2550 microcontroller based control card. Application results show that the speed control performed provides practical and easy control, is convenient, sensitive, and economic and also can immediately be adapted to different applications compared to the present analog control.