What is an Inverter System? An inverter system stabilizes the amount of voltage and frequency produced by a petrol engine driven alternator through the supply of "sine wave" electricity, with a distortion ratio of less than 3%. That's why Yamaha Inverters are the ideal power source when using precision equipment or micro-computer controlled electrical appliances. More Controlled, Clean Power Yamaha's Inverter system produces AC current within a controlled electrical circuit process, known as PWM (Pulse Width Modulation). As a result, fluctuations in engine speed do not affect the voltage or frequency of the electrical output while at the same time reducing output emissions. Multi-Polar Alternator System The adoption of a multi-polar alternator enables the generation of more efficient, high frequency 3-phase AC current that the inverter than turns into single phase. The high efficiency alternators on a Yamaha Inverter achieve a much lighter and more compact generating unit than conventional 2-pole rotor type alternators. Smart Throttle Yamaha's Smart throttle feature automatically adjusts the engine speed to precisely match the energy load. this means much quieter, more efficient engines that run and last longer. Unbeatable Noise Block Yamaha's Noise Block feature, an acoustically engineered sound reduction system , utilises various sound absorbing materials, moulded cases, an intake silencer, fibreglass insulation, plus newly designed mufflers and fans to provide virtually silent running while maintaining the highest quality performance. Quiet Muffler & Low Oil Shut-off At the heart of every generator is a strong Yamaha engine that delivers powerful and consistent performance, that's so quiet you'll forget its running. Every generator includes an approved spark arrestor and a low oil shut-off system for long life and added peace of mine.