This is the third and last article in our series on VFDs.

The fundamentals of pumped water systems.

They are known by many names: VFDs, variable frequency drives, variable speed drives, adjustable speed drives, inverters, etc.

The simplest method of starting a three-phase pump motor is by closing a contactor and allowing the motor to start at full voltage, or “across-the-line,” as it is called.

Consider this scenario: You go to a flea market, and spot an electric motor that looks similar to the one on the wash-down pump in your barn that is starting to make noise.

Why do pump motors fail?

This month, we will cover the other two main components in a standard panel – the contactor or starter, and the overload protection devices.

A three-phase pump control panel is the interface between the incoming three-phase power and the pump.

"The last two articles in this series on electricity focused on single-phase pumped water systems. This article will be the first of several on three-phase systems."

A look at pump and motor protection in a single-phase system, the potential problems and the available solutions.