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How Variable Transformers Reduce Harmonic Distortion

Today, there is an increased supply of nonlinear loads such as computers, electric motor drives, power converters, etc. Each of these devices draws a certain amount of non-sinusoidal current from the input power supply and can distort the sinusoidal current and voltage waveforms, referred to as harmonics. In other words, frequency changes within electrical distribution systems cause voltage and current variations, or harmonic distortions.

What is Harmonic Distortion?

Harmonic distortion frequently happens in facilities with a heavy presence of electronic devices and can cause damage and disturbance, such as overheated wires and power loss. Typically, harmonic distortion occurs as the electrical device is introduced to the network. This is also where your variable transformer comes in to play.

Harmonic Distortion Sinusoidal Current Wave Example

Example of a sinusoidal current (left) and example of a harmonically distorted current (right)

Volt-Pac Motorized Variable Transformer

How Variable Transformers Eliminate Harmonic Distortion from the Input Source

A variable transformer is a simple, rugged method of controlling electrical voltage, current, and power. This type of power regulator operates by absorbing utility line voltage and providing continuously adjustable output voltage. Typically, a variable transformer is used to obtain AC voltages different from the average 120 or 240 volts (single or three-phase supply), or to deliver test voltages from lines where the voltage fluctuates above or below the norm. No matter the application, your variable transformer should provide a specified power level to the load with minimal loss to the primary frequency.

Superior Electric POWERSTAT® Variable Transformers are designed with the technology to prevent it from “adding” or “eliminating” harmonic distortion, a feature that is ideal when applied to test equipment. No matter what THD (total harmonic distortion) is on the input source in your application, the POWERSTAT variable transformer will produce that same value in the output. The POWERSTAT variable transformer is a low impedance device, popular for features such as efficiency, versatility with various PF (power factor) loads, and it’s the ability not to affect your system’s harmonics.

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POWERSTAT® Variable Transformers

POWERSTAT® Variable Transformers provide excellent power regulation with negligible variation in output voltage from no-load to full-load current. They take input line voltage and provide continuously adjustable output voltage and are offered with motorized, high current rating and other options.
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