DOL starting 3 Ph Motor and an RCD

[gerard]

Hi all,

I finally got the 30mA Si RCBO in today. I installed it and I'm afraid (for me!) it was bad news. It tripped instantly with the leakage current created by the Inverters. I could try an RCBO with a higher mA rating but I thought the Si range are designed for such applications. So there you go-any more suggestions on how to go about this problem?

 

[sparkyjames]

OK. Lets clarify this for the recent new posters...

The RCD is at the socket that the portable machine is plugged in to.

Gerard has the job in hand by replacing said RCD with a special type.

When he has fitted the new RCD I'm sure he'll post back here with his results.

Clear?

With reply's like this Im reluctant to post here anymore. Sorry chap PM me if you like.


James

 

[netblindpaul]

Hi all,

I finally got the 30mA Si RCBO in today. I installed it and I'm afraid (for me!) it was bad news. It tripped instantly with the leakage current created by the Inverters. I could try an RCBO with a higher mA rating but I thought the Si range are designed for such applications. So there you go-any more suggestions on how to go about this problem?

At what point in the cycle of the machine?
Was this immediately on power up, were the motors being driven?

 

[gerard]

Yes - it happened on start up. It tripped immediately once the start button was pressed.

 

[spark 68]

Hi Gerard,

Any chance of posting the datasheet for the SI type RCBO ? or the part number ?

Edit: and the inverter/ vfd drive you are using ?

 

[gerard]

Hi Gerard,

Any chance of posting the datasheet for the SI type RCBO ? or the part number ?

Edit: and the inverter/ vfd drive you are using ?

I will do but not until the 27th as i am not back to work till then. I know there a two cfw 10 weg inveters driving the motors

 

[silva.foxx]

With reply's like this Im reluctant to post here anymore. Sorry chap PM me if you like.


James

And your point is?

New Boy Ducks head and waits for flack

New Boy assumes flack, doesn't duck but makes petulant statement.

 

[spark 68]

Hi Gerard,

I managed to find the datasheets for the WEG VFD's, just when you get a chance for the RCBO's datasheet, no hurry.

 

[gerard]

Hi Gerard,

I managed to find the datasheets for the WEG VFD's, just when you get a chance for the RCBO's datasheet, no hurry.

Will do - thanks for that. Probably be the 27th before I get it for you. In the meantime I will scour the Schneider website - tried earlier but their site was v. slow so packed it in.

 

[silva.foxx]

I will do but not until the 27th as i am not back to work till then. I know there a two cfw 10 weg inveters driving the motors

You recently stated the inverters were

... It's a WEG CS10 - two of them.

:yesnod:


http://catalogo.weg.com.br/files/wegnet/WEG-cfw-10-a-users-guide-0899.5202-manual-english.pdf


​

Take a look at page 86, parameter P297... switching frequency. Decrease it. I have seen in IMO manuals that switching freq. contributes to RCD tripping.

 

[gerard]

I will double check - sorry about that. I'm pretty sure they are CFW-10 drives, I will check this out.

 

[Specialist]

With reply's like this Im reluctant to post here anymore. Sorry chap PM me if you like.


James

Hi James: Don't really understand what your problem is with the replies gerard has been given, especially Silva's quoted reply. gerard does'nt seem to have a problem with it, so maybe you could explain ?

 

[lewlec]

hi all

been installaing a few abb vsd's and under manufacturers info it specs that if using rcd's they must be of a B type..... 300ma td. unsure if this is the case with other drives but i would imagine that it is because of high earth leakage.

hope this is of use

regards
gary

 

[gerard]

hi all

been installaing a few abb vsd's and under manufacturers info it specs that if using rcd's they must be of a B type..... 300ma td. unsure if this is the case with other drives but i would imagine that it is because of high earth leakage.

hope this is of use

regards
gary

Thanks for that I will order one and give it a go - no harm in trying. I will post my results when I find out

 

[netblindpaul]

lewlec,
Almost certainly due to high earth leakage by design of the drives rather than by any faults though.