Research And Insight

Frequency converter

A frequency converter – or variable frequency drive (VFD) – is an electric device that converts a current with one frequency to a current with another frequency. The voltage is normally the same before and after frequency conversion. Frequency converters are normally used for speed regulation of motors used to drive pumps and fans.

A frequency converter is an electric device that converts a current with one frequency to a current with another frequency. The voltage is normally the same before and after frequency conversion. Frequency converters are normally used for speed regulation of motors used to drive pumps and fans.

The following example shows how this works:
A fan is provided with a current of 400 VAC, 50 Hz. At this frequency (50 Hz), the fan can run at a certain speed. To get the fan to run faster, a frequency converter is used to increase the frequency to (for example) 70 Hz. Alternatively, the frequency can be converted to 40 Hz if the fan is to run slower.

For variable speed control, Grundfos E-pumps have a frequency converter built-in, and the Grundfos CUE is an external VFD that works with standard pumps in a range of applications.

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