This project is engaged for industrial drafting fan for applications like textile mills, chocolate factory, and wire drawing units.
A programmable microcontroller from 8051 family is engaged to provide different speed at different times. A low voltage BLDC motor is driven by a power MOSFET in PWM mode drive which is derived from a microcontroller. The duty cycle of the PWM increases progressively in steps.
The power supply consists of a step down transformer 230/12V, which steps down the voltage to 12V AC. This is converted to DC using a Bridge rectifier. The ripples are removed using a capacitive filter and it is then regulated to +5V using a voltage regulator 7805 which is required for the operation of the microcontroller and other components.