HIGH VOLTAGE DC UPTO 2KV FROM AC BY USING DIODE AND CAPACITORS IN VOLTAGE MULTIPLIER CIRCUIT

The project is designed to develop a high voltage DC around 2KV from a supply source of 230V AC using the capacitors and diodes in a ladder network based on voltage multiplier concept.

The method for stepping up the voltage is commonly done by a step-up transformer. The output of the secondary of the step up transformer increases the voltage and decreases the current. The other method for stepping up the voltage is a voltage multiplier but from AC to DC. Voltage multipliers are primarily used to develop high voltages where low current is required. This project describes the concept to develop high voltage DC (even till 10KV output and beyond) from a single phase AC. For safety reasons our project restricts the multiplication factor to 8 such that the output would be within 2KV. This concept of generation is used in electronic appliances like the CRT’s, TV Picture tubes, oscilloscope and also used in industrial applications. The design of the circuit involves voltage multiplier, whose principle is to go on doubling the voltage for each stage. Thus, the output from an 8 stage voltage multiplier can generate up to 2KV. As this is not possible to be measured by a standard multimeter, a potential divider of 10:1 is used at the output such that 200V reading means 2KV. Due to low input impedance of the multimeter, the reading would actually be approximately 7 times the input AC voltage.

Further the project can be enhanced to generate the high voltage DC up to the range of 30-50 KV by increasing the number of stages. It can then be used for required industrial and medical applications.

NOTE: The project needs to be handled with utmost safety as touching any high voltage even with a multimeter could be fatal. The company is not responsible for any eventual accident.

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AUTOMATIC DIALING TO ANY TELEPHONE USING I2C PROTOCOL ON DETECTING BURGLARY

The main objective of this project is to intimate the concerned authorities about an unauthorized access of secured areas such as museums, residential houses, banks etc. As crime rate is on the rise and burglars are getting smarter, the security system for banks, shops and houses needs to be full proof. This proposed system ensures that at any moment if any unauthorized person tries to open the bank locker; a telephone number will be dialed through the telephone line connected to it.

This project uses a microcontroller from 8051 family. An external memory EEPROM is interfaced to the microcontroller to store the contact number to which the call is to be made. The arrangement is made in such a way that when someone tries to open the door forcefully even when it is locked the microcontroller gets an interrupt through a hidden switch mechanism interfaced to it. Microcontroller will automatically dial to the number which is stored in the EEPROM through DTMF encoder interfaced to it. Microcontroller fetches information from external memory like EEPROM using I2C (Inter IC communication) protocol.

Further this project can be enhanced to use a cell phone or GSM modem with a serial camera connected to it. The camera will take photographs and sends it over MMS/ email attachment to the concerned authorities.

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THREE PHASE FAULT ANALYSIS WITH AUTO RESET ON TEMPORARY FAULT AND PERMANENT TRIP OTHERWISE

 The project is designed to develop an automatic tripping mechanism for the three phase supply system. The project output resets automatically after a brief interruption in the event temporary fault while it remains in tripped condition in case of permanent fault.

The electrical substation which supply the power to the consumers i.e. industries or domestic can have failures due to some faults which can be temporary or permanent. These faults lead to substantial damage to the power system equipment. In India it is common to observe the failures in supply system due to the faults that occur during the transmission or distribution. The faults might be LG (Line to Ground), LL (Line to Line), 3L (Three lines) in the supply systems and these faults in three phase supply system can affect the power system. To overcome this problem a system is built, which can sense these faults and automatically disconnects the supply to avoid large scale damage to the control gears in the grid sub-stations.

This system is built using three single phase transformers which are wired in star input and star output, and 3 transformers are connected in delta connections, having input 220 volt and output at 12 volt. This concept low voltage testing of fault conditions is followed as it is not advisable to create on mains line. 555 timers are used for handling short duration and long duration fault conditions. A set of switches are used to create the LL, LG and 3L fault in low voltage side, for activating the tripping mechanism. Short duration fault returns the supply to the load immediately called as temporary trip while long duration shall result in permanent trip.

The concept in the future can be extended to developing a mechanism to send message to the authorities via SMS by interfacing a GSM modem.

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INDUCTION MOTOR PROTECTION SYSTEM

The project is designed to protect an induction motor from single phasing and over temperature. Providing a protection system is very important in industries, using lot of motors such that production is not hampered owing to failure of any motor.

The basic idea for the development of this project is to provide safety to the industrial motor/pump/lift Motor etc. If any of the phases, out of the 3 phases is missing or if the temperature of the motor during operation exceeds the threshold value, motor stops immediately. The system uses a 3-Phase power supply where three single phase transformers are connected to it. If any of the phases is not available the corresponding transformer stops supplying power to the circuit. This leads to one of the four relays getting switched OFF. The main relay which is powered through a set of four relays gets disconnected because of one relay not being powered. Thus the main relay that delivers 3 phase supply to the motor gets disconnected. A thermistor is connected to the motor body to sense the temperature. If the temperature increases then supply to the fourth relay is disconnected.

Further the project can be enhanced by using current sensors for over load protection and phase sequence sensor for protecting the motor from applying wrong phase sequence.

 

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CELL PHONE CONTROLLED ROBOTIC VEHICLE

The project is designed to develop a robotic vehicle that is controlled by a cell phone. DTMF commands from a phone are sent to another cell phone which is mounted on the robot. These commands are fed to a microcontroller of 8051 family to operate the vehicle movement through motor interface.

The main scope of project is to send commands from one cell phone to be received by another cell phone mounted on the robot to receive the DTMF (Dual Tone Multi Frequency) mode commands which are then decoded by a DTMF decoder. The corresponding codes are then fed to a microcontroller, programmed to recognize those codes to operate 2nos DC motors through motor driver IC for any direction movement as per the sent commands from sender’s mobile. The motors are controlled using motor driver IC which is interfaced to the microcontroller. It uses microcontroller from 8051 family and a battery for power source.

Further the project can be enhanced by interfacing it with additional motors for multipurpose activity. For example, it can be developed into pick n place robot or fire fighting robot with water pump etc.

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