Several electrical machines are known to output a pure sine wave. Here are some commonly used devices that generate a pure sine wave:
Alternators/Generators: Alternators are commonly used in power generation systems, such as in power plants or portable generators. When driven by a mechanical power source, alternators produce alternating current (AC) with a pure sine wave output.
Power Inverters: Power inverters are electronic devices that convert DC (direct current) power into AC power. Inverters that are designed to produce a high-quality output waveform typically generate a pure sine wave. These inverters are often used in applications where clean and stable AC power is required, such as in sensitive electronic equipment, renewable energy systems, or for powering household appliances during power outages.
Uninterruptible Power Supplies (UPS): UPS systems are backup power devices commonly used to provide temporary power during electrical grid failures. UPS units that provide pure sine wave output are called "online" or "double-conversion" UPS systems. These UPS units convert incoming AC power to DC power and then generate a pure sine wave AC output using an inverter.
Frequency Converters: Frequency converters are devices used to convert the frequency of an AC power supply. Some high-quality frequency converters produce a pure sine wave output, especially those designed for precision equipment, laboratory use, or specialized applications.
Some Motor-Generator Sets: Motor-generator sets consist of an electric motor mechanically coupled to a generator. In certain applications, such as in some precision testing or laboratory equipment, motor-generators can be used to generate a pure sine wave output.
It's important to note that while these devices are capable of producing a pure sine wave, not all electrical machines or equipment generate a pure sine wave. Some devices, such as square wave inverters or modified sine wave inverters, produce waveforms that deviate from a pure sine wave and may introduce harmonic distortions or other irregularities.