Saturday, 12 January 2013

SINGLE PHASE AUTOMATIC TRANSFER SWITCH WITH OVER CURRENT PROTECTION USING PIC16F877


 FEATURES:
*May add frequency sensing
  • Over current protection
  • Over voltage protection
  • Under voltage protection
Mode of Operation:
 The default source of power is the utility supply. In a situation where the utility supply voltage is below 210V or above 270V the system would start the generator and cut of the utility supply, provided that the generator voltage is also within the specified range. In a case where both sources are out of range, no power would be supplied until one of them comes into the voltage range.

The current sensor monitors the current drawn. When the current goes above 10A, the system is cut off completely, a message is displayed instructing that the fault be cleared and the reset button press afterwards.

The LCD constantly displays the Voltages of both sources, the current drawn as well as the states of both sources(whether they are on or off)

THE VARIOUS PARTS

Voltage Sensor:
 
Simple step down and rectification is used

Current Sensing:










Current is sensed using an acs712 current sensor from allegro

Power Sources:


Display Unit and Relay Driver:














Microcontroller:

Download Design files and Code here!

Wednesday, 9 January 2013

Microcontroller Based Automatic Three-Phase Change Over Switch

.......Work in PROGRESS!!


Features
Over voltage protection
Under voltage protection
Protection against Unbalance due to one or more phases going off
Etc etc.