For the satisfactory working of all devices, it is suggested to permit voltage at setting limits. Voltage variations in electric power supply definitely have adverse effects on different loads. These voltage fluctuations can be caused by several reasons such as voltage surges, overload, lightning, etc. Over voltages are the voltages that beat the normal values which cause insulation loss to electrical appliances leading to short circuits. Likewise, under-voltage causes overloading of the apparatus leading to lamp sparks and ineffective performance of the apparatus. Thus, this article is proposed to give over voltage and under voltage protection.To understand this concept and know it well, one request to go through this concept.
Over Voltage and Under Voltage Protection
The main goal of this project is to make a low voltage and high voltage indicator. The proposed system will save expensive electrical and electronic appliances from the opposing effects of over voltage and under voltage protections. The circuit of this system features an auto reset and uses easily available components. It makes use of the comparators available inside 555 timer ICs. Supply is selected from different points of the power supply circuit for the display and control circuit operation to attain reliability.
The main function of a transformer is to convert AC electricity from one voltage to another with a slight loss of power. Step-up and step down transformers are used to increase and decrease the voltage. It consists of primary and secondary coils, where the primary is an input coil and secondary is an output coil. There is no electrical connection between the two coils; as an alternative they are allied by an alternating magnetic field formed in the soft-iron core of the transformer.
- The comparator LM339 comprises of four independent precision voltage comparators
- The series of LM339 was intended to directly interface with TTL & CMOS.
- When operated from power supplies, this series will directly interface with MOS logic where their low-power drain is a separate advantage over typical comparators.
Features of Comparator
- Wide single supply voltage range 2.0VDC to 36VDC
- Very low supply current drain-0.8㎃, independent of supply voltage-1.0mw/comparator at 5.0VDC
- Input biasing current is low-25㎁
- Input offset current is low (±5㎁), and offset voltage
- The voltage range of input common-mode includes GND
- Differential i/p voltage range equivalent to the power supply voltage
- Low o/p 250㎷ at 4㎃ saturation voltage
- Output voltage well-suited with TTL, ECL, DT, MOS & CMOS logic system
- The sensitivity level of moisture is 3
The diode is used to convert AC into DC, and these diodes are used as a half wave or full wave rectifier.
- The Rs resistor is connected in series with the Zener diode to limit the flow of current through the diode with the voltage source, VS being connected across the combination.
- The stabilized o/p voltage is taken from across the Zener diode.
- This diode is connected to its cathode terminal connected to the positive rail of the DC supply so it is reverse biased and will be operating in its breakdown condition.
- The BC547 transistor is an NPN Epitaxial Si Transistor.
- This is a general-purpose transistor in small plastic packages.
- It is used in general-purpose switching, amplification BC847/BC547 series 45 V, 100 mA NPN general purpose transistors.
- Whenever base terminal is high, then current flows through the base & emitter and after that only current will pass from collector to emitter.
- The relay is a electromagnetic switch, used to control the electrical devices
- Copper core, magnetic flux plays main role here
Relay Driver ULN2003
- Relay driver ULN is a monolithic high voltage, high current Darlington transistor arrays.
- It comprises of 7-NPN Darlington pairs that features high-voltage o/ps with common-cathode clamp diode for switching inductive loads.
- The collector-current (CC) rating of a single Darlington pair is 500mA.
- The Darlington pairs may be paralleled for higher current capability.
- The ULN functions as an inverter.
- If the logic at input 1B is high, then the output at its corresponding pin 1C will be low.
An inductive load contains of a load formed by a wire wound coil, like in a relay or solenoid, a transformer, or any load which uses a winding over a magnetic iron core. Breaking an inductive load is generally more simple than breaking a resistive load and will normally produce heavy arcing.
The main intention of this project is to design a low voltage and high voltage tripping mechanism to guard the load from damage. The variation in AC mains supply is common in homes and industries.The complex electronic devices in these situations can get simply damaged. It is desirable to have a tripping machine to protect the load.
This system will trip the load in the occurrence of the input voltage falling above or below to a set value. Two 555 timers are used as window comparator, which delivers a fault o/p if the i/p voltage to them crosses the range beyond the voltage window.A relay is then functioned to cut off the load for security reasons. A lamp is used as load in this project.
The proposed system can be enhanced by integrating an alarm, that gives an alert when voltage Variations occur. It can also be interfaced with a GSM modem to deliver alert message to the operator via SMS to take suitable action.Furthermore, any doubts regarding this concept or to implement over voltage and under voltage protection system please give your valuable suggestions by commenting in the comment section below.Here is a question for you, what are the applications of over voltage and under voltage protection system?