The Mitsubishi FR-E720S-0.75K is a compact, high-performance inverter belonging to the FR-E720S series, specifically designed for single-phase 200V input voltage applications. With a rated capacity of 0.75 kW, this inverter is primarily used to control the speed of three-phase asynchronous motors, enabling precise variable-speed operation while significantly reducing the high inrush current typically associated with direct motor starting.

In industrial and commercial settings, the primary purpose of using a variable frequency drive (VFD) like the FR-E720S is to adjust motor speed according to load requirements, thereby improving energy efficiency, reducing mechanical stress, and enhancing process control. To achieve variable voltage and frequency output, the inverter first converts the incoming single-phase AC power into DC power through a process called rectification. This is typically accomplished using a diode bridge or a rectifier circuit.

The DC power is then smoothed and stored in a capacitor bank before being converted back into AC power by a device known as an inverter. In scientific and engineering terminology, the component that performs the DC-to-AC conversion is called an "inverter." While standard inverters generally produce a fixed-frequency, fixed-voltage AC output, a variable frequency drive such as the FR-E720S is designed to generate an adjustable-frequency and adjustable-voltage output.

The output waveform of the FR-E720S is a simulated sine wave, typically achieved through pulse-width modulation (PWM) technology. This quasi-sinusoidal waveform is suitable for driving three-phase induction motors, allowing smooth speed control over a wide range. As a result, the device is often referred to as a variable frequency drive or a variable speed drive, widely used in applications such as fans, pumps, conveyors, and other machinery requiring adjustable motor speed.