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OffTheShelf equipment to produce unity power factor in supply to 6 pulse,3ph rectifiers?

Z

zenerbjt

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Hi,
Supposing we have a 10kW installation. -Consisting of a three phase supply. Each phase is transformed (50Hz transformer) down to 40VAC with a mains transformer. Then there are a huge number of 3-phase, 6 pulse rectifiers feeding off the 40VAC. These provide power to loads of 40W power supplies.

As you know, the current waveform in each phase will not be pure sinusoid in this case.

However, is there any equipment that can be bought, which can be put “in-between” the 50Hz mains transformer, and the six pulse rectifiers, which will result in the supply current and voltage both being sinusoidal and in-phase with each other?
--- Updated ---

Eg, By the way, can the use of an Electric motor/machine help correct the power factor in this case.?
 
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For practical reasons, power factor correction would be performed on the 230/400V primary side. It's surely possible with harmonic filters, but quite bulky last century technology. Rotating converters could be used as well.
 
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Easy peasy

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Solid state active harmonic filters exist - they go on the 230/400 side of the equipment a provide unity power factor looking in from the mains supply ...
--- Updated ---

you can also put chokes on the mains side of the transformers or in the AC or DC line of the rectifiers to raise power factor quite a bit.
 
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BradtheRad

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Even though you mention pulse rectifiers...

3-phase (delta) through six ordinary rectifiers, combined results in a relatively smooth waveform.

3-phase delta 40VAC 6 diodes DC unfiltered to resistor 10kW.png

A mere 1 mH inductive choke reduces ripple to a small amount. It's a question whether to construct one inductor to carry 240A, or to split the burden among several inductors.

To use capacitive filtering requires several Farads. And it must tolerate 240 A.
 

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