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Vsd At A High Distance


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#1 shatabdi

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Posted 05 February 2009 - 05:45 PM

i have VSD 400 m away from motor. it is not possible to relocate either of them.
what option do I have , to suppress harmonics and meet EMC regulations ? do I have limitation for using shielded cable for control cable from motor to VSD?
We have asked for external filter but from the catalogues , I am not sure that this distance is workable. can someone guide me?

#2 marke

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Posted 11 February 2009 - 05:45 PM

Hello shatabdi

Yes, there are limits to the maximum length of cable that can be connected to the output of a VFD and a shorter length for screened cable.
These limits are the maximum that the VFD can be connected to and still be reliable.
These cable lengths vary considerably between different VFDs and different manufacturers so this information needs to come from the manufacturer.
In addition, there are limits to the lengths of the cable that can be connected and the installation still operate with in the EMC requirements or CE.
In general, it is necessary to use a screened cable in order to comply with the EMC emissions regulations, and with some VFDs, it is possible to use up to 150M of screened cable and still comply, but with other designs, the maximum cable length can be as short as 5 meters.
Your supplier should be able to tell you what the limits are for you VFD.

Some suppliers can provide additional filters that you connect to the output of the VFD to extend the maximum cable length and comply.
You need to talk to your supplier to get a definite answer.

Best regards,
Mark.

#3 shatabdi

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Posted 15 February 2009 - 08:27 AM

QUOTE (marke @ Feb 11 2009, 11:15 PM) <{POST_SNAPBACK}>
Hello shatabdi

Yes, there are limits to the maximum length of cable that can be connected to the output of a VFD and a shorter length for screened cable.
These limits are the maximum that the VFD can be connected to and still be reliable.
These cable lengths vary considerably between different VFDs and different manufacturers so this information needs to come from the manufacturer.
In addition, there are limits to the lengths of the cable that can be connected and the installation still operate with in the EMC requirements or CE.
In general, it is necessary to use a screened cable in order to comply with the EMC emissions regulations, and with some VFDs, it is possible to use up to 150M of screened cable and still comply, but with other designs, the maximum cable length can be as short as 5 meters.
Your supplier should be able to tell you what the limits are for you VFD.

Some suppliers can provide additional filters that you connect to the output of the VFD to extend the maximum cable length and comply.
You need to talk to your supplier to get a definite answer.

Best regards,
Mark.


Thank you Mark . for me the length is 400 m , and supplier insists 400 m is not possible for him . I hve asked for filter . any site where I can check what filter to be selected for certain distance ?
Regards

#4 marke

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Posted 15 February 2009 - 05:42 PM

The difficulty that you have, is if you require EMC compatibility, then you must comply with the manufacturers instructions. Adding a filter may allow operation over 400M with out damage to the VFD, but unless you pay a lot for testing, will not comply with EMC requirments in terms of providing proof of operation.
Additionally, unless you have the manufacturers recommendations as to the filter to use, you will not know if the filter will provide sufficient protection for the VFD for reliable operation.

If the supplier is not able to give recommendations, you need to change supplier.

Best regards,
Mark.

#5 acdrive

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Posted 05 July 2009 - 10:44 AM

I think the distance seems a bit long. There is alway limitation for length between the motor and VSD.

Maybe you can contact the manufacturer for more.




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