Induction generators are widely used in small-scale power plants driven by renewable energy, such as wind, mini/micro-hydro, tidal wave, biomass, biogas, etc. In applying this generator to a micro-hydropower plant, it is usually equipped with an ELC (Electronic Load Controller), which regulates the frequency to remain constant at a safe tolerance limit (49.8 – 50.2 Hz). However, this system is still not optimal because the ELC dumps its excess power into the dummy load. This paper proposes an ELC system that can adjust the frequency to remain constant without wasting excess power from the generator. This system uses the working principle of a bidirectional converter, which can regulate the flow of power from the generator and dummy load in two directions. In the proposed system, the dummy load uses a battery to store excess electrical energy and be utilized and reused when needed. Performance analysis of the proposed system uses simulation with MATLAB Simulink software. The induction generator used has a voltage specification of 380 Y, 50 Hz, 1420 rpm, 3.5 A, and 1.5 kW. The analysis results show that the developed ELC design can adjust the frequency in the value range of 49.98-50.01 Hz during load changes with a range of 955 Watt to 1.045 Watt, with the response time reaching its steady-state value of 0.1-0.4 seconds.

The main function of the ampifier is to increase the signal strength, in terms of its voltage or current. In this research, a multistages ac voltage common-emitter amplifer and common-collector amplifier with a single supply of +15 V was designed. The objective is to design an amplifier for amplifying a small ac signal from a transducer. The transducer has an output impedance of 10 k. The amplifier will have a small-signal gain in order of about 1500 and a small-signal bandwith ranging from 100 Hz to 20 kHz. It will drive a load of 300 Ω. The entire circuit consists of a first stage common-emitter configuration gain amplifier, another second stage common-emitter configuration gain amplifier, and a third stage buffer unity gain common collector amplifier. The three-stages was capacitor coupled. The overall gain of the entire amplifier is the product of the first-stage gain, the second-stage gain, and the third-stage gain. A method called short-circuit time constants was used to determine the apropriate coupling and bypass capacitors. The overall circuit was then simulated by using NI Multisim. The magnitude of the overall gain of the circuit was obtained by performing an interactive analysis and simulation. The frequency response of the amplifier was obtained by performing an AC sweep analyses and simulation. It can be showed that the amplifier’s overall gain obtained from simulation is in agreement with the calculated results. The simulated result for the frequency responses were also in agreement with the requirement

This paper deals with the gas production by monoester oil intended to be used as insulating oil under an electrical discharge of low energy. The monoester contains only saturated fatty acids in its hydrocarbon chain. The electrical fault was realized by implementing an AC high voltage to hemispherical shaped electrode pairs with the gap of 2.5 mm immersed in the oil sample. The voltage application was paused when the breakdown occurred in oil and re-applied repeatedly up to 50 and 75 times to allow a high concentration of gasses produced by the oil sample. The resulting gasses were extracted from the oil sample using the headspace method and then analyzed using gas chromatography (GC). Fault identification methods, like DGA status, Key Gas, Duval Triangle, and IEC Ratio, were performed to predict the fault causing the production of such gasses. The results are compared with those of the monoester of unsaturated type. It is found that the Key Gas method is applicable for both oils under electrical discharge. The Duval Triangle and the IEC Ratio methods diagnose the electrical discharge in both monoesters but overestimate them as high energy discharge.

The challenge of regularly charging the battery of cellular phones has brought about new and more convenient ways to realising cellular battery charging. The wireless power platform has been explored for years bringing about many dimensions to its realisation. In this research, developed a wireless charging of Li-Ion battery of a cellular phone using commercial-off-the-shelf components vis-a-vis Radio Frequency (RF) energy. A MAX2623 voltage controlled oscillator was used to generate RF signals at a frequency of 915 MHz. Through a series of amplifier stages, the signal is radiated using a half-wave dipole antenna. The signal is received by a remote receiver module made up of 5 dBi gain half-wave dipole antenna which is impedance matched to a bridge rectifier made of SMS3929 Bridge Quad Schottky low turn-on voltage diodes. The rectified output is received by a EH4205 low voltage booster which amplifies the input into two paralleled MAX 682 charge pumps. The paralleled MAX 682 charge pump delivers a constant output voltage of 5 V DC and current of 500 mA. Within a 4 m radius the receiver module can receive enough power for the realisation of wireless battery charging.

The safe movement of Light Vehicles (LVs) is jeopardised on underground mine ramps due to the single lane nature of ramp and the use of ramp by Heavy Vehicles (HVs). Two-way traffic flow dynamics in single-lane underground mine haulage ramps do affect productivity of ramp in times of ore transportation from underground to the surface for processing. In this research, we made use of traffic signal lights, Radio Frequency (RF) Transmitters (Tx) and Receivers (Rx) and a traffic signal lights module to safeguard LV motion on underground ramp. Simulation outcomes confirm safe movement of LV in the midst of HV and other LV on the haulage ramp. This development assures of safety of LV and stands to minimise the incidents occurrences rate in mine ramp haulage systems.

Radar tsunami merupakan salah satu alat deteksi yang digunakan pada system peringatan awal tsunami. Radar tsunami yang umum digunakan adalah radar High frekuensi yang memiliki jarak jangkauan jauh tetapi daya besar dan resolusi rendah. Untuk meningkatkan keandalan system peringatan tsunami dalam mendeteksi tanda-tanda tsunami dan monitoring dengan kecepatan update informasi yang tinggi, maka diperlukan system radar dengan resolusi yang tinggi. Resolusi yang tinggi dapat diperoleh jika radar memiliki bandwidth yang besar dalam spectrum radio. Peningkatan bandwidth dapat dilakukan dengan menaikan frekuensi kerja radar. Antena merupakan salah satu komponen penting yang dapat menentukan performa system radar. Oleh karena itu pada penelitian ini dirancangan antenna pada Super High Frequency untuk diaplikasikan pada system radar. Antena yang dirancang adalah antenna microstrip dengan patch rectangular. Spesifikasi yang diinginkan pada frekuensi 5,8 Ghz yaitu return loss≤-10 dB, VSWR≤2, bandwidth >150 Mhz, beamwidth>200. Setelah rancangan menggunakan simulasi memenuhi spesifikasi maka dilakukan pabrikasi dan pengukuran. Hasil pengukuran didapatkan pergeseran frekuensi menjadi 5,71 Ghz dengan return loss -21,346, VSWR 1,186, Bandwitdh 200 Mhz dan beamwidth 400 Oleh karena itu dapat dikatakan bahwa antenna yang dirancang dapat digunakan pada system radar tsunami

The timely maintenance of haulage machines is important to prevent machine breakdown and reduce productivity down time. An unintended breakdown or machine stop due to inadequate maintenance causes huge financial loss to the company due to delivery delays. Excessive maintenance also increases production cost due to down time and workshop maintenance. Most haulage companies like Mantrac Ghana Limited have a maintenance schedule for their customers. However, most of these customers do not maintain these machines on time, largely due to forgetfulness or sheer disregard for the maintenance schedule. It is thus important to implement an automatic alert system to notify operators of this machinery when it is time for maintenance. This paper seeks to design an automatic alert system using ATmega328 microcontroller, SIM900 GSM module and alarm unit. A sensor connected to the engine of the haulage machine is used to monitor the condition and operational hours of the machine. The microcontroller is programmed using proteus software to receive instructions from the sensor and issue commands to activate both the GSM module and the buzzer simultaneously. The type and time of maintenance to be done is displayed on the LED display. A corresponding message is sent via the GSM module to both Mantrac Ghana Limited and the customer to undertake the type of maintenance. It can be concluded that an automatic alert system would improve strict adherence to maintenance schedule and help reduce machine.

PLTH Bayu Baru is one of the hybrid power plants (HPP) located in Baru beach, Pandansimo, Bantul, Yogyakarta, Indonesia. It generates electrical energy from two sources, wind and solar energy. However, a problem is encountered regarding wind turbine mechanics due to using a manual switch for braking during periods of excessive wind speed. This study proposes an automatic wind turbine braking system through a utilized fuzzy logic controller (FLC) for the PLTH Bayu Baru application. The Mamdani type FLC without complex mathematical models is applied to the Arduino Uno development board to realize the proposed systems. The error (Error_V) and delta error (dError_V) values from the generator voltage sensor become the input of the proposed systems, while the pulse width modulation (PWM) becomes the output for controlling the on/off period of the MOSFET as switching devices. The proposed systems have been tested on a micro-scale wind turbine with PMSG 12V/400W type. From the testing results, the proposed system successfully braked automatically at the point wherein the generator voltage exceeds the setpoint value. Also, the proposed system keeps the generator voltage less than 13.8V, so the problem caused by excessive speed can be resolved.

Surabaya is a city with an area of 326.81 km2 and is the center of land transportation in the eastern part of Java Island. The construction of digital infrastructure in the Surabaya area will make it easier for the City Government to make efficient services. Traffic accidents that occurred in Surabaya until 2017 recorded 1,365 incidents. EVAN (Emergency Vehicle Automatic Notification) is a research topic that focuses on the field of transportation, especially in real-time traffic accidents which can be integrated with city information centers and hospitals for primary assistance in accidents. The purpose of this research is to make it easier for the Surabaya city government to provide first aid in the event of an accident. The design of the device on the user side is made using the Arduino, the accelerometer sensor and the gyroscope in the form of the MPU6050 sensor and the u-blox gps module. Crash detection on the system using the k-Nearest neighbors algorithm (KNN). On the operator side, the design is done on a web basis by utilizing the ReactJs framework which is integrated with the Google Maps APIs. The results of the accuracy of the accident detection system reached 97% and the detection of accident locations and the nearest hospital from the location reached 100%. Thus, real-time accident detection can be implemented in Surabaya city to support the smart city.

Food is an essential aspect of the laying hens' cultivation process. The delay of the feeding time and the short amount of food can cause stress to the hens. Furthermore, an excessive amount of food can cause overweight and reduce hens' productivity. This paper provides a method to automate the feeder for laying hens using a device based on microcontroller technology. A tool that can detect chicken behavior when hungry and the temperature of the cage can provide an excellent feeding management system for the breeder. The automatic feeder can see chicken behavior, also the environmental condition around the cage. A specific noise amplitude caused by the hungry hens can trigger the feeder. This feeder also design aims to provide the food in the right amount at the right time. Thus, the breeder can minimize the stress of laying hens, reduce food waste, and keep the hens ideal. Here the system can save the chickens food around 13.76% more efficient.