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After a decade hiatus, I have dusted off my Yaskawa Sigma II servo drives and have started laying out a control box.
Finding the right parts can be a challenge. The Yaskawa documentation recommends 'T' type EMI filters. I must be not using the right search parameters because my searches are not yielding any useful results.
Do the type of EMI filters really matter for servo drives?
Thank you.
https://www.murata.com/en-us/product...c/chapter06-p3Quote:
Originally Posted by oxford
Hi,
'T' type EMI filters have two inductors, crucially one as the first element at the input and one as the last element at the output, and one capacitor between them.
'PI' type EMI filters have two capacitors, one at the input and one at the output (from the line and neutral) and one inductor in series between them.
A VFD output has very high frequency switches and they LOATH switching capacitive loads, it causes huge current spikes in the semiconductor devices
right at the moment of switching which is bad news for reliability. For this reason a 'T' type filter is recommended as the VFD 'sees' the inductor....not the capacitor.
On the 230V line side of the VFD there is little practical difference between them. At the output of the VFD, that's where the switches are exposed and a 'T' type is required.
Commonly VFD manufacturers don't recommend EMI filters on the output UNLESS the length of cable between the VFD and motor is over 50' say. Unless you need it I
wouldn't bother with a filter on the output, but your installation will improve its overall noise performance by having good EMI filters on the 230V input side.
Given that 'PI' types are the most common, and are perfectly acceptable on the 230V side I would not insist on a 'T' type.
Craig
Just use the allen bradley's. There are tons on ebay cheap, search for 2090-uxlf-106 (6amp) -110 (10 amp) , -336 36 amp), these are just some examples.
Thank you for the detailed explanation Craig.
Since I'm only going to be running about 9 ft max of cable, it looks like I don't need an EMI filter on the output, and I don't really need to worry about what kind of EM I filter I use on the input so long as it is rated high enough.
Thank you for the recommendation. I will look for some of these today.Quote:
Originally Posted by Halfnutz
How many Drive and what size are theyQuote:
Originally Posted by oxford
You would not be using a EMI Filter on the output, who ever suggested it, is talking Bs, if you where to use anything on the output it would be a 3% output line reactor, only for the input is a EMI Power Filter used and in some case's required, if you want to keep the return power clean, and your cabinet EMI noise low, ( 1 ) sized for all your drives would be all you need for the input powerQuote:
Originally Posted by oxford
They are RFI filters and are not suitable for EMIQuote:
Originally Posted by oxford
You can get a quality EMI filter from any of the electrical suppliers, that is cheaper and the correct filter to use, what you list is RFI filters which is not suitable for EMIQuote:
Originally Posted by Halfnutz