What is a VFD Line Reactor

Many of the components that make up a variable frequency drive (VFD) are semiconductor components, which are sensitive to power or current surges, voltage spikes, line distortion, and general power anomalies. A line reactor is an optional component that can be added to a drive system to protect the VFD and other devices from power surges and transients. A line reactor is essentially an inductor—a coil of wire that forms a magnetic field as current flows through it. The magnetic field limits the rate of rise of the current, which reduces harmonics and helps avoid unnecessary tripping of the drive.

A reactor can be referred to as either a line reactor or a load reactor, depending on where it’s installed. A line reactor (also called an input reactor) is installed before the VFD and protects the drive, while a load reactor (also called an output reactor) is installed after the VFD and protects the motor