LAMP LIFE EXTENDER BY ZVS (Zero Voltage Switching)
ABSTRACT
The
project is designed to develop a device to increase the life of incandescent
lamps. Incandescent lamps exhibit very low resistance in cold condition due to
which it draws high current while switched ON, resulting in fast failure.
Random
switching of lamps may switch the load at peak supply voltage. When such
switching occurs while the lamp is having low resistance (cold condition) then
the current further shoots up (at the time of peak supply voltage switch ON)
leading to premature failure of the lamp. The proposed project provides a solution
by engaging a TRIAC in such a way that the switch ON time is precisely
controlled by exactly firing it after detecting the zero cross point of the
waveform of supply voltage. This would result in current waveform rising from
zero at the time of switch to full value, thereby increasing the life of the lamp.
The project is having
comparator which is used for ZVS output. The ZVS (zero voltage switching) is given
as reference interrupt to the microcontroller of 8051 family. A push button is
used for switching ON the lamp at zero voltage of the supply voltage so the
lamp draws current gradually from zero to full value.
Further the project can
be enhanced by using three TRIACS, one in each phase for three phase load
switching.
BLOCK DIAGRAM:
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