A line reactor (also referred to as a “choke”) is a variable frequency drive (VFD) accessory that consists of a coil of wire.


Line choke is an inductance connected to the VFD input or output circuit. It is a component that forms a magnetic field as current flows through it and when the current increases, it limits the increment in current by producing a voltage or emf across it that opposes it.

This protects the VFD from unwanted spikes, transients and harmonics. Reactor is used either on input side or output side of VFD.

When a reactor is used on the input side, it is called a line reactor and when it is used on the output side, it is called a load reactor.