The above calculations clearly show that the RPM, frequency and voltage of the generator are extremely linear and proportionate to each other. When in DC load mode (Fun1), the device will place a fixed load onto the power source until it’s manually stopped. The voltage setting in this mode is a low-voltage alarm. The current can be changed while the load is running. A reasonably calculateddummy load is attached in series with the ELC, and P1 is adjusted such that the dummy load slightly illuminates and adjusts the generator speed and frequency to the correct level as per the required specs. One-part of an LM358N op-amp (IC2) is used here as the core component. The 10K multi-turn preset potentiometer (P1) lets you adjust the current fine and precise. I have designed the circuit to use a logic level MOSFET IRL540N (T1) so that we can power the circuit from a voltage much smaller than 9V. Any logic level power MOSFET with an appropriate voltage/current rating should do, but I also tested the design with another MOSFET IRLZ44. Since the MOSFET works as a resistive element, it dissipates heat depending on the current flowing through it. To extend the power range of the load, you need to attach a suitable heatsink to the MOSFET. Similarly, the 1R resistor (R3) dissipates quite a bit of power, a proper heatsink is crucial here, too. The 1uF capacitor (C4) across the MOSFET is very essential to prevent unwanted oscillations. The dummy loads are all terminated sequentially via PNP buffer transistor stages and the subsequent NPN power transistor stages.

Once you get your board, you can proceed with assembling all the components. My finished board looks something like this shown below. This device requires a 12v DC power source separate from the load itself, to power the logic circuitry. Microcontroller SectionSince controlling water flow cannot be a feasible option, controlling load in a calculated manner becomes the only way out for the above discussed issue.

This section consists of required program flow-related declarations of integers and variables. Also, we set the associate peripherals pins with Arduino Nano. const int slaveSelectPin = 10; // Chip select pin int number = 0; int increase = A2; // Increase pin int decrease = A3; //decrease pin int current_sense = A0; //current sense pin int voltage_sense = A1; // voltage sense pin int state1 = 0; int state2 = 0; int Set = 0; float volt = 0; float load_current = 0.0; float load_voltage = 0.0; float current = 0.0; float voltage = 0.0; LiquidCrystal lcd(7, 6, 5, 4, 3, 2); // LCD pins It is still a switching device and instead of applying a DC to the gate to partially switch on the gate, i am switching the fet between cut-off and saturation to average the current to the desired level. A well calculated high wattage dummy load is attached with a sole mosfet controller stage at pin#3 of IC#2.Under this situation if a few of the appliances are switched OFF would relieve the generator from some load resulting in an increase in its speed, however the increase in the speed would also create an proportionate increase in voltage at pin#5 of the IC. Conversely if the pot resistance is reduced, the triac is restricted to conduct proportionately for a much smaller section of the phase cycle, making the load weaker with its activation.