Inversion methods explained

Industrial power inverters divide into two types, distinguished by the size of their transformer and the switching speed of their transistors.

The iron does the surge work. An inverter’s ability to absorb the electrical surge inherent in motors, pumps and torque-related tools is directly proportional to the physical amount of iron in its transformer. A massive iron core can absorb a surge because of the flywheel effect stored in it.

The transistors set the class. The size, tolerance and switching speed of the field-effect transistors used in the inversion process are what make a design high or low frequency. Low-frequency inverters use larger, more robust FETs that run cooler.

Deciding between the two for a purchase? Introduction to mobile power inverters weighs them on cost, size, surge and working life.

High frequency (HF). The large majority of inverters sold at retail are high frequency. They carry over twice the component count and use multiple smaller transformers, which is what makes them cheaper and more compact — and what limits their tolerance for industrial loads. They suit tool battery chargers, small appliances, audio, video and computers, but have reduced capacity for sustained exposure to high surge loads like pumps, motors and some high-torque tools.

Low frequency (LF). Built around the massive iron-core transformer, with fewer and larger transistors that operate cooler. That construction is what gives an LF inverter its surge capacity and its working life under heat and vibration.

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