DOL starting 3 Ph Motor and an RCD

[silva.foxx]

hi all and thanks for your help. I have a 3ph socket with a 100mA RCD and it is running fine with that. So, as someone pointed out, the 30mA RCD doesn't get on too well with the VFD. Now that this has happened, I do remember this happening before(a long time ago) and probably should have known better. thanks again.

Does this 100mA RCD satisfy personal safety? If the lead of this portable equipment become damaged and exposes a live conductor, does this 100mA RCD offer correct protection to the poor sod that picks up this cable and receives a new hair-do? .

 

[Darkwood]

Does this 100mA RCD satisfy personal safety? If the lead of this portable equipment become damaged and exposes a live conductor, does this 100mA RCD offer correct protection to the poor sod that picks up this cable and receives a new hair-do? .

This is a common problem with having inverters in portable equipment and really a good all round solution dosnt exist, because leakage is expected to cause nuisance tripping you have to depart from the reg's on this occasion and make it as safe as practically can be done, this includes using cable with earthed braiding and having earth circuit monitors on, the regs are not always practical in every situe but as long as counter measures are taken then youve done you bit.

 

[gerard]

I am going to check the regs but is a 100mA RCD not better than none?! If I make everything as safe as possible then what else can I do?

 

[victory12]

agree , paul. the correct terminology is " shove a megger up it"

Have you taken any IR readings? I can't understand why you've got a RCD on the drive, but never the less it shouldn't trip it. Makes you wonder why your other department gave it away?
________________
virtual assistant

 

[Robo1401]

If the motor is not faulty then why not just take out the RCD and install a 10A triple pole type C or D mcb? This would allow for the higher starting current and provide the necessary protection needed for this type of circuit?....

 

[gerard]

I want to protect against leakage current and an MCB won't do this. At the moment it is protected with an MCB - still waiting for supplier to get an Si type RCD and this will solve problem - hopefully!

 

[sparkyjames]

What make is the VSD as some are able to disconnect the filters that cause the tripping by a simple jumper inside the terminal cover. This is a risk based procedure based on the sites requirments for 30mA RCD prtection vs EMC issues. New Boy Ducks head and waits for flack:tounge_smile:

 

[gerard]

It's a WEG CS10 - two of them.

 

[silva.foxx]

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?

 

[gerard]

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?

I sure will. As I said -I'm just waiting for part to come in, there is a delay for some reason.

 

[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


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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.