High Harmonic Filter Help

I'm assuning that this filter needs to be connected into your power supply some how. Also, what harmonics are we talking about, and who's giving you heat about the harmonics in the first place?

Have you looked into what are called ferroresonant transformers? They have a pretty narrow bandpass, as transformers go. As I don't know what your application is, that's my best shot for now.

--Europium

HF oven

I think you may like to try some ferrite cores and film capacitors like mylar. I suspect that your intention is to reduce artifacts reversing backwards into the power line.

I would use the ferrite cores to make chokes. Bypass them with capacitors in pairs, forming filter sections in series.

To eliminate the problems

First must know Load characteristics i.e.

What frequency of induction in used?

Is it square or quasi-square wave or sine-wave?

Good practice is to track down this info at working location

Then decide and design the appropriated filter

Remember that it is 400 KVA filter, even 5% loss = 20 KVA

If inductor wire merely 0.001 ohm at 1KA will yield DC loss of 1KVA

If Hi-freq skin effect of wire will triple that heat

If used ferrite core Hysteresis will quadruple the heat

If capacitor ESR merely 0.001 ohm heat loss will need big blowers

Simple filter may interact and ruin the main induction power circuits

Knowledge details design. You're deal with 30 cubic feet filter box

All LC's components must be custom make.

One month to investigate and design solutions

One month to order and fabricated parts

One month to test and finalize GOOD LUCK

Title may be "High Frequency Harmonic Filter Help"

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Hello! Please help me!

How can I make high harmonic filter for 1000A, 0.4kV electricity? For iron melting factory which works by induction.

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Your system must be:

1000A= the crucible's current & 400V line voltage of Utillity-power Line; 3 phase; HF Furnace, self resonating to the load in Crucible, Water cooled...; frequency Range Self-Resonating [nearly 500KHz]

Is it correct?

One thing you should keep in mind that if you are using OEM HF Furnace you need not to worry about HAMONICS being fed back to Power-line; as all is catered for by manufacturer.

If it is indiginously assembled then you should know the insight of Power-filter-design. Simple Ferrite core Rings etc will not work & will over-heat due to magnetic-losses.

Look for off-the-Shelf Power Filters from renowned manufacturers, they may help.

Haajee, I really enjoy the way you write, and your delightful use of words. I really do.

Thought I'd tell you that!

--Europium

Thanks & regards

Thanks and Kind Regards.

I Think " It is never too late"

What frequecnies do you want to shunt? What are the load characteristics? Power Factor? One phase, or 3 phase lines? Is the harmonic coming from the power source Bad transformer) or from the load (motor)? What side of the transformer do you want to put the filter on? Are they harmonics or just noise? How did you measure them? Why are you trying to reduce the harmonics? Is it causing another problem?

What is the actual problem you are trying to solve? Was it working fine until you added one more system to the load? Does removing the system stop the harmonics? Do you want a low pass design, if so do not put induction in series, as this will get really hot and waste electricity. Look at putting a capacitor in parallel to return at the load to correct the power factor and shunt any noise signals. Also see if the motor is balanced using the same current on all phases. If your harmonic frequencies are not related to the rotation of the motor in the line and are instead induced from a different source, try to sheild the lines radiating the signals or sheild the power lines from other sources and transformers nearby.

At these high currents, magnetic fields from adjacent lines can be a problem. See if they run in parallel to the lines you have noise on for a significant distance.

Can you describe the transmission line diagram from the source to the load? Finding the cause of the harmonics may be less expensive than putting a Capacitor across the load to ground (as is typical solution for shunting high frequencies.) The size of the Capacitance depends on the frequency, the load impedance and the voltage max.