In this “Did You Know” article we will discuss line reactors. Reactors, also known as “inductors,” are coils of wire wound around a chunk of iron.
Depending on where they are used whether on AC or DC, you might hear other terms such as: AC Reactor, DC Link Inductor, or choke.
The older school guys will call them “chokes” because that’s exactly what they do. They choke currents in electricity. The largest use for reactors is VFDs. VFDs have a bank of capacitors internally. Think of these as batteries. When the power is supplied to these batteries, the last thing you want to happen is to instantly charge them. One, it’s bad on the capacitors, and two, it causes a short burst of current. Both cause extra heating in VFDs. VFDs also draw non-linear current. For the power company, this is seen as harmonics. By adding a reactor in front of the VFD you extend the life of the drive and reduce harmonics. The placement of the reactor in front of the drive on the line side is referred to as a “Line Reactor.”
The products used for Line Reactors are the KLR and KDR series from TCI.
Reactors come in 3% ratings and 5% ratings. The larger the %, more the “choke” you get.
So, who uses Reactors?
Any user of VFDs is a good place to start. Reactors are an economical solution to extend the life of the VFD and reduce harmonics. Reactors have other uses on the output section of a VFD as well. This will be covered in another “Did You Know” article, titled Load Reactors.
Special thanks to National Power Quality and
Consulting for providing these Did You Know articles.
For electrical consulting needs, NPQC can be contacted at www.natpowerquality.com