RCD tripping when inverter running

[Beavertooth]

Guys I have invested heavily in a 3 phase motor running through an inverter to give me speed control & reverse. I'm building a 2.000x50mm belt linisher. My RCD is tripping. All the research I do is from the same problem but a few years back. So I'm hoping there may be a current solution now. My RCD is 80amps, I've got a 100amps,not fitted yet. Been told it won't make any difference. Can anyone advise on such a problem. It cost me a lot of £s so can't can't just roll over & cry. Thanks. Ps. I live in N. Ireland so standard 240v.

 

[skotl]

Definitely RCD, not MCB? An MCB trips when over load, but an RCD trips when there is a leak to earth. The latter, of course, is a far more serious issue...

A pick of the breaker would be helpful.

 

[carbon]

I’ve found this, check what type of rcd is fitted

https://inverterdrive.com/howto/How-to-Use-Inverter-Drives-with-RDC-Earth-Leakage/

 

[garethp]

Does it trip as soon as you turn the power on to the inverter or when the motor starts to run or does the motor run for a period of time before tripping?

 

[grim_d]

I was Informed yesterday about EMC filters tripping RCD, funnily enough from the salesman at inverter drive.

What inverter is it? Some can have the filters bypassed to avoid this.

 

[Seadog]

My RCD trips when I switch off. So I switch off the MCB first.

 

[brightspark]

chances are your rcd is a 30 ma. some inverters wont work on less than 100 ma and some even 300 ma best phone t5he firm who supplied it and ask them otherwise your just guessing. if it is the case and your not on a tt system and electricity board supply the earth you can wire it without the rcd in the line separately but that's only if the supplier says thats whats causing the problem. I once got one to do its a real pain let us know how u get on with it

 

[Beavertooth]

Definitely RCD, not MCB? An MCB trips when over load, but an RCD trips when there is a leak to earth. The latter, of course, is a far more serious issue...

A pick of the breaker would be helpful.

Sorry Skotl, I have no clue what is meant by "a pick of the breaker."

 

[Ruffian]

A pickture of the breaker which blows,

Its mig welder slang forum saturday

 

[brightspark]

Sorry Skotl, I have no clue what is meant by "a pick of the breaker."

he means is it the minature circuit breaker works on overload or an rcd trip switch that works on earth faults that is tripping

 

[WorkshopChris]

Is this the main supply RCD? and does it still trip with absolutely everything else in the property turned off at the circuit MCB? So all that is on is the VFD.

 

[Beavertooth]

I was Informed yesterday about EMC filters tripping RCD, funnily enough from the salesman at inverter drive.

What inverter is it? Some can have the filters bypassed to avoid this.

It was made up at the electric motor shop where I bought it. When I came home it worked fine. It been sitting for a while. I was going to purchase another similar system from a M8, & his tripped. So I tried mine again & it was tripping. The company where I bought it has closed down. All I can tell you is it has good parts but that info is probably useless.

 

[Beavertooth]

Is this the main supply RCD? and does it still trip with absolutely everything else in the property turned off at the circuit MCB? So all that is on is the VFD.

I need to test that. It's a good point for when it worked when I brought it home, no one else was home. The next time was in the evening, winter, so that may have help trip it. I'll test tomorrow.

 

[Beavertooth]

he means is it the minature circuit breaker works on overload or an rcd trip switch that works on earth faults that is tripping

All I know it's the RCD that trips & I have to re-set it.

 

[Beavertooth]

Does the size of the RCD make any difference??? Like I said, it's 80amp & I have a 100apm one.

 

[WorkshopChris]

Does the size of the RCD make any difference??? Like I said, it's 80amp & I have a 100apm one.

Absolutely none, in this instance.

 

[brightspark]

Does the size of the RCD make any difference??? Like I said, it's 80amp & I have a 100apm one.

its not the amperage that counts its the earth leakage tripping current that's measured in milliamps that counts

 

[Kram]

First, does it trip instantly, when running, under heavy load, just occasionally, or when things get hot?

There are types of RCD's and there are different types of leakage, plus different amounts.
AC leakage happens on basic AC electricals, lights, normal motors etc.
DC leakage can happen on electronics power supplies and inverters like VFD's. Anything with a DC bus and switching.

Most RCD's are the basic AC only type 30ma. It is possible DC leakage can trip an AC type well below its trip current, but can also cause them not to trip. They are expensive because of EV car charge points need them.

If your motor cable has a screen that is earthed, and it should, that is where a lot of leakage comes from, as well as the EMC filter. Shorter cable = less induced leakage and less likely to trip.

Disabling the EMC filter is considered a bodge.
If short cable doesnt help I would try a different RCD, which sparkies might frown upon, as there is some nonsense about not mixing brands.

 

[brightspark]

[QUOTE="Kram, post:
I would try a different RCD, which sparkies might frown upon, as there is some nonsense about not mixing brands.[/QUOTE]its not nonsense reason being fitting wylex breakers in to a volex db they will fit yes but if there is an accident or the db sets on fire who is to blame wylex or volex then insurance companys wont pay out and your left hi and dry. each manufacturer makes the different types of rcd to fit in to there boards if u do want to fit a mismatch just put it in to a separate enclosure and it then doesnt matter

 

[Onoff]

Been through something similar. To comply with CE marking they (drives) have to have EMF filters thus inverters are known to be a bit leaky. Option to fit a drive WITHOUT filters but then it's not CE compliant. Or...fit a 100mA trip...but an obvious no-no on some kit, some clients won't have it etc. So, what to do. Well Merlin Gerin do their Multi-9 "Si" RCD for "sensitive installations". Worked for me, we used to have about a 25% tripping rate. Don't get the "Si" confused with an "S" type though.