An inverter is a powerful oscillator that turns DC power into AC power. You can have pure sine wave inverters and modified sine wave inverters, among other types. Pure sine wave inverters are slightly more expensive than other types. This is enough to ask if a pure sine wave inverter is necessary. The short answer is yes. But to understand why you must first know what a pure sine wave inverter is. You must also know about waves and harmonics, as well as why harmonics can damage equipment.
Here is what a pure sine wave inverter means:
A pure sine wave inverter produces a voltage that forms a sinusoidal wave over time. A sinusoidal wave can be a sine wave, a cosine wave, or anything in between. In fact, a sine wave and a cosine wave are just phase-shifted versions of the same thing. A sinusoidal wave is a smooth periodic oscillation, unlike a square wave or a sawtooth wave.
Here is how waves work
All waves act like sums of sinusoidal waves of different frequencies (often called Fourier series). Here, each frequency has a specific amplitude. The lowest non-zero frequency is called the fundamental frequency. The higher frequencies, called harmonics, are multiples of the fundamental frequency.
So, a sinusoidal wave is a wave where the fundamental frequency has a non-zero amplitude and the harmonics all have an amplitude of zero. Every other type of wave has harmonics with non-zero amplitudes. If these harmonics are unintentional, then they form what we call harmonic distortion.
Here is how it applies to inverters and appliances
In the USA, an inverter has a fundamental frequency of 60Hz. If it is a true sine wave inverter, then it won’t have any harmonics. Or at least they will be negligible. If not, then the inverter will produce harmonics. These harmonics are like having inverters of different frequencies operating in series. This means that their voltages can add up.
Appliances can handle the 120/240V 60Hz AC power. But those with AC motors don’t work well with the other frequencies (harmonics). The appliances will lose efficiency and generate a lot of heat. The harmonics can even damage or destroy appliances and equipment. These can include refrigerators, microwave ovens, vacuum cleaners, and air conditioners.
In summary, you will need a pure sine wave inverter because it doesn’t produce harmonics. Harmonics are harmful to equipment that have AC motors. Much of this equipment includes things you use in your home.