Author Topic: Inverters and Filters  (Read 2626 times)

Offline appletree

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Inverters and Filters
« on: July 27, 2015, 07:54:49 AM »
Views required please, I have a Mitsubishi single to three phase inverter on my lathe and I also a Jaguar and a 2.2kw Mitsubishi on other machinery.
I appreciate I should ideally fit RFI filters, however it is potentially more important as I am about to have Solar panels fitted.
Has anyone any experience using filters and are generic ones ok or do you need specific manufacturer ones?

Tried to paste link to one on ebay without success but this is the item number 331231707786 Phil

Online David Jupp

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Re: Inverters and Filters
« Reply #1 on: July 27, 2015, 09:18:37 AM »
Not much detail to judge that one on (and I'm no expert).

One thing I do know is important, the filter should be mounted on the same (earthed) backplane as the inverter and as close as practicable to the inverter.  The mains feed to the inverter should be via the filter, with no intervening components.

Offline PK

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Re: Inverters and Filters
« Reply #2 on: July 27, 2015, 05:32:15 PM »
The only problem you may encounter using a generic filter is that it may not attenuate the noise enough, conversely, it may be overkill for the job. The manufacturers filter will have components selected to get the noise levels below an accepted standard.
If you can find the inductance and capacitance values used in the manufacturers filter, then you can select a generic version with confidence.

For my machines at home, (which all run from 240VAC single phase) I just use a generic filter like this:


Offline bertie_bassett

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Re: Inverters and Filters
« Reply #3 on: July 27, 2015, 05:47:29 PM »
Have you spoken to the company installing the panels? If they have done any commercial places they may have come across this issue befor and may be the best ppl to advise.
a competent engineer uses the tools and knowledge available, to get a challenging job done.

 An incompetent "engineer" tells his boss that the existing equipment "can't do the job" and to get another machine

Offline appletree

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Re: Inverters and Filters
« Reply #4 on: July 27, 2015, 06:01:36 PM »
I am using a   comercial electrical company for the solar panels rather than a firm that has moved on from seling upvc windows, drives or conservatories. They should be able to advise, no dubt they will say yes to filters, I was just seeing what others had done

Offline PekkaNF

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Re: Inverters and Filters
« Reply #5 on: July 27, 2015, 10:50:36 PM »
You also need to put tht filter and VFD into metal enclosure and use screened cable to the motor.

This sort of stuff:

That diagram is good:
just the inverter and filter in emi-tight metal enclosure. You also need proper cable glands.

I have been using this kind of filters:

I probably still have some european made left.

When you have some of this type EMI filters the leakage current might be enough to trip RCD. Then you want "low leakage model". Older good ones definately had enough current to trip the RCD.

Some industrial/computer equipment has IEC Inlet Filters (Power entry module). Which is nice because you can use IEC computer mains cable in it and it will provide good screening on cabinet. No need for shielded cable gland. Filtering is not the greatest and on domestic computer supply the current rating might be on the low side, but this is an option if you have the junk allready.

Panels/inverters shoulf have pretty substantial over voltage protection and some sort of filtering. You actually could get some interference from the PV inverter.


Offline appletree

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Re: Inverters and Filters
« Reply #6 on: July 28, 2015, 05:46:03 AM »
Hi Pekka
Thank you for your input, some good information there, hopefully the installer is coming Wednesday so we will discus things then.