A Comparison of Performances of Electronic and Electromechanical Energy Meters

The Ferraris (electromechanical) energy meter has had predominance in the metering of energy consumption using the alternating current supply system. Electronic energy meters are gaining popularity because of the possibility of remote reading and controllable non uniform rate of billing. In this work, an electronic energy meter which does not use a multiplier circuit but uses a voltage to frequency converter with frequency to voltage converter in the feedback loop was designed and built. The performances of this electronic meter were compared with those of the Ferraris meter. It is shown that at light loads, the errors of the electromechanical meter are greater than those of the electronic meter

AN AUTOMATED RAILWAY STATION TRAFFIC CONTROL SYSTEM

Majority of accidents experienced with railway transportation involve collision with automobiles or other vehicles and collision with other trains. These collisions can be averted by putting safety measures in place. Part of the measures can be achieved by using computerized railway station traffic control systems that use microcontrollers and electromechanical devices to shift traffic from one rail lane to another and also to operate the level crossing gate. The two major stages of the system being described here are thus the track switching stage and the level crossing gate stage.  The system makes use of microcontrollers for decision making. The microcontrollers are programmed to detect signals from sensors and to output the processed signals to control electromagnetic devices through motor drivers. The codes for the microcontrollers were written in PIC Basic programming language and were debugged and compiled using Micro Code Studio Integrated Development Environment. The resultant Hex files were programmed into the memory of the microcontrollers with the aid of a universal programmer. Software simulation was carried out using the Proteus virtual system modeling software. A scaled down prototype of the system was built and tested. The prototype was able to execute all the decisions required to control the given railway station. A practical real life system would require the scaling up of the power required to drive the various motors; the logic of the system would however remain unchanged. The inclusion of the automated traffic control lighting system at the level crossing gate in the system eliminates the fatigue and tedium associated with a manually controlled traffic system. The computerized railway station traffic control system which helps in track switching and level crossing gate traffic control is capable of improving reliability, speed, operational safety and efficiency of the railway transportation system.

An Automatic Safety Control for Immersion Water Heater

The heating of liquids, especially water, is carried out in the homes and industries for various reasons. The domestic water heater has become a near- ubiquitous appliance in the Nigerian homes. An important source of concern with this appliance is the frequent possibility of outbreak of fire due to negligence on the part of the user. This paper describes an immersion water heater that is free from such hazards. The safety condition is achieved by incorporating a device, which automatically switches off power from the heating element when the water level drops below a certain mark