Line reactors improve power quality, protect equipment, and reduce harmonics. Learn how Westek Electronics supports reliable industrial power systems.
Line reactors are essential electrical components used in industrial power systems to improve power quality, protect sensitive equipment, and enhance the reliability of variable frequency drives (VFDs), motors, and other power electronics. Engineers specifying these reactors need to understand how they work, where they should be applied, and how they support compliance with Australian power quality standards and electrical system design requirements.
What is a Line Reactor?
A line reactor is essentially an inductor, a device with coils of wire that creates a magnetic field when electrical current flows through it. This magnetic field resists sudden changes in current, which helps stabilise electrical systems. In industrial installations, line reactors are installed in series with the power line feeding VFDs, motors, and other sensitive equipment.
Line reactors may be used on the input side (between the supply and the VFD) to mitigate supply disturbances, or on the output side (between the VFD and the motor) to reduce electrical noise and reflected waves.
How Line Reactors Work
A line reactor introduces inductive impedance into the circuit, meaning it resists rapid changes in current and smooths power flow. This results in:
• Attenuation of voltage spikes
• Reduction in harmonic distortion
• Lowered electromagnetic interference (EMI)
The inductance of a reactor determines how effectively it limits surges or harmonics, and this is typically expressed as a percentage impedance rating, such as 3% or 5%.
Line reactors also act as a low-pass filter, presenting greater opposition to high-frequency harmonics than to the fundamental frequency of the system. This helps limit the impact of harmonics generated by power electronics, such as VFDs, on the broader electrical network.
Types of Line Reactors and Their Applications
Input (Line-Side) Reactors
Installed on the incoming supply to a VFD, input reactors help:
• Reduce current surges
• Mitigate voltage notching
• Prevent overvoltage trips
They are a common best practice in industrial systems where supply disturbances may arise from grid irregularities or large loads.
Output (Load-Side) Reactors
Used between the VFD and the motor, load reactors smooth PWM output waveforms, reducing:
• Voltage spikes
• Reflected waves
• Motor insulation stress
Both input and output reactors can be critical in applications with long cable runs or sensitive motor equipment.
Selecting the Right Line Reactor
When choosing a line reactor, engineers should consider:
• Impedance rating (%Z): Higher percentages offer more filtering but may introduce voltage drop.
• Application context: Input vs load side placement.
• Voltage and current ratings: Ensure reactors match system specifications.
• Compliance factors: Align with Australian standards and site electrical design requirements.
Westek Electronics’s range of line reactors includes products engineered for diverse industrial applications, such as TE Schaffner’s RWK3044 and RWK3062 series, which are optimised for 400 V and 690 V networks, respectively, and help meet power quality performance expectations.
Line Reactor Selection for Industrial Power Systems with Westek Electronics
Line reactors are indispensable components for engineers designing or maintaining industrial power systems. They deliver practical benefits such as improved power quality, enhanced equipment protection, harmonic mitigation, and compliance alignment. At Westek Electronics, we understand that knowing how these reactors function, where they should be installed, and how to select the right model is essential to achieving reliable power system performance.
For expert guidance on selecting the right line reactor for your application, contact us, a trusted supplier of high-quality electronic products backed by local expertise and technical support.
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