1.0 Introduction To Automatic Voltage Regulators
Automatic voltage regulators (AVR) in power supply unit is a device which is used to regulate or stabilize electrical power supply for electrical or electronic appliances. This device helps automatically to keep the voltage level from the public power supply system constant. In other words, the minimum and maximum ranges of voltage are maintained in order to achieve a constant output of 220v.
This devices also serve as a protective device for appliances connected directly to it, while the AVR is connected directly to the public supply. The protective system in AVR either regulate or stabilize it to 220v output for the safety of our appliances or the fuse in the AVR will rupture by excess current of the surge and thereby cut-off the incoming power supply.
The stabilization and regulation is achieved through the control circuit which include relays and other components of various voltages from the secondary winding of the auto-transformer used in this project work.
This control circuitry, does the work of cut and boost in the case of higher and lower voltage respectively. If the supply voltage drops below 220V down to 180V,the primary control does the work of the boost which brings the output to normal , while when the voltage increases beyond 220v up to 260v ( which is not ideal), it does the work of cut. The coils of the relay are triggered by the 11.5V D.C from the last stage of the operational Amplification. By this arrangement, an improved automatic voltage regulation is achieved and, is hereby presented in this project.
Different techniques have been employed in the design of AVR circuits in recent times but, in the design and construction of this particular type, high rise voltage, excess current due to dangerous condition externally like lightening effect which may appear on the power supply lines were effectively isolated. The system chips and fragile devices were protected likewise low voltage fluctuations make-brake power supply from public power supply were taken good care of in this AVR construction.
1.2 Objective of This Project
The automatic voltage regulator of rating 2KVA is a natural choice for remote control device for the consistent voltage level fluctuation of our power supply system. Therefore, we bear the following in mind as our objective while carrying out this project;
- To fully understand the automatic means of controlling and regulating the system, Its practices, design, construction, operation and application in public electric power system engineering
- To test the electric power behaviour of systems or appliances connected to AVR. Also to perform both practices network computers, televisions, amplifier sets and other sensitive devices intended to be protected from direct connection to public electric power supply.
- To practically engage in and fully understand the AVR operational modes and technology or configuration in electrical design and construction
- To enhance power regulation and stabilization technology via automatic voltage regulation for our electrical and electronics appliances due to voltage variation and, incessant power —fluctuations.
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