ABSTRACT
SCR (silicon controlled rectifier) based DC motor control is very useful in industries because they offer a continuous speed variation of 0 to maximum. These drives are static and have good reliability. These drives work under the principle of phase angle control. By means we are varying the triggering angle from 0 to 180 degree in every half cycle of rectified 50HZ AC mains to get the speed variation. When triggering angle varies the applied average voltage to the motor also varies. The rpm of dc motors have direct relation between rpm and applied voltage.
The triggering angle variation is achieved by a microcontroller whose operation is hardwired to get ac synchronization with the applied ac mains. The motor is controlled by the microcontroller circuit according to the speed desire which is set by a variable knob provided to the user. The microcontroller collects the input voltage set by the knob control and with the help of the synchronization signal from the ac mains provides triggering pulses in each half cycle. The triggering pulses are the applied to the gate of thyristors in the drive through a pulse transformer which is used for isolation.
For our project we use the popular PIC microcontroller (PIC 16f 73) from MICROCHIP CORPORATION. The drives are created by 25A SCRS. For our project we use 1HP dc motor to control.
The triggering angle variation is achieved by a microcontroller whose operation is hardwired to get ac synchronization with the applied ac mains. The motor is controlled by the microcontroller circuit according to the speed desire which is set by a variable knob provided to the user. The microcontroller collects the input voltage set by the knob control and with the help of the synchronization signal from the ac mains provides triggering pulses in each half cycle. The triggering pulses are the applied to the gate of thyristors in the drive through a pulse transformer which is used for isolation.
For our project we use the popular PIC microcontroller (PIC 16f 73) from MICROCHIP CORPORATION. The drives are created by 25A SCRS. For our project we use 1HP dc motor to control.
BLOCK DIAGRAM
CIRCUIT DIAGRAM
PLEASE post code pic16f73
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