Inverters are not only divided in terms of their power capacity and into standard or customized inverters. They are also divided based on their waves into sine wave inverters or ‘true’ or ‘pure’ sine wave, modified sine wave and square wave.
1. Sine wave inverters
Your local utilities and generators rotating AC machinery produce sine waves, which are natural products of rotating AC machinery. The biggest advantage of investing in these inverters is that most equipment is designed for sine waves.
This ensures tha equipment, such as microwave ovens and motors, works to full specifications. There are also some appliances, such as light dimmers, bread makers and some battery chargers, that need sine wave to function. It is this increased need and applications of sine wave inverters that make it twice or more expensive than others.
2. Modified sine wave
These inverters have a square wave-like waveform with an additional step or two. They may work well with most equipment, but compromises the equipment’s power or efficiency. Some equipment, such as motor pumps, fans, and refrigerator pumps, consume more power from the inverter because of low efficiency.
Motors usually consume 20% more power because most modified sine wave inverters have higher frequencies, which motors cannot use. This is why you may notice that fluorescent lights are not as bright as usual, or hear some buzzing or annoying humming noises.
Even appliances with digital clocks and electronic timers will not work properly because their timing depends on power. As modified sine waves are noisier and rougher than pure sine waves, the clocks either fun faster or don’t work at all.
3. Square wave
These are the cheapest inverters that safely run simple things such as tools with universal motors. But they are not seen around much these days because square wave inverters do not have many applications.