KR200C tripping out rccd

Hi,
There is nothing wrong with the robot.
We use our robots in different locations a lot, and have these problems sometimes.
300ma should be ok normaly, but it can be different between brands.
Ask the electrician if he can try a different brand or a higher amp rate.

Phase order doesn't matter for a robot, the mains input feeds a 3-phase rectifier, everything beyond that is powered off a DC bus (note: some KRCs have 3-phase cooling fans, where it *might* make a difference, but not necessarily, depending on the fan geometry). The problem is that servo drives and servos on a robot this size are a ginormous energy sink when they start. It doesn't help that there's no galvanic separation from the mains all the way up to the motors, so any actual leakage that does happen counts against the RCD limit.

Is KR200C modern enough to have six separate servo drives and independent brakes? Try jogging A6 only, maybe try disconnecting A4 and A5 motors for that test, too (robot shouldn't notice as long as you don't try to move them, they won't be affected by gravity even with brakes open). I'm not sure if the result is going to be of any practical significance even if it doesn't trip the RCD, maybe it could help you convince the electrician to provide a circuit with no RCD ("See? Nothing wrong with it, just pulls too much power in an instant when all six motors start together.")

i have also a 30mA type AC RCD and trips sometimes when i try to jog and every time

i shutdown the krc2 controller.

I have contacted kuka and told me that krc2 needs 300mA RCD

type F is the correct type that is needed but because it costs more than 500 euros

you can try a 300mA type A RCD that is cheap (< 50euros).

If 300mA trips there is more that 300mA leakage..

rest electric installation is correct ? neutral and PE must be connected together before RCD...

Only 30mA RCD protects humans

300mA RCD protects from leakage only the machine NOT humans 300mA for humans are deadly.

In what country are based ?
It depends on local regulations if you need an RCD in a industrial situation.

Read this https://www.electrical-installation.org/enwiki/Types_of_RCDs

B is the correct type of RCD to install but the problem is that cost about 600 euros.

Type A costs under 50 euros.

Leakage is from line filters in krc2 cabinet.

NO each robot needs it's own RCD not one central RCD for all installation..

For example a cheap option is 40A/300mA/type A RCD under 50 euros and should work.

Not solved 100% because 300mA are deadly for humans.

This is leakage protection only for machine not for humans.

Perhaps the best solution is 30mA type B but i don't know if it works 100% and it costs about 500-600euros

Next best solution is type A 300mA with very good ground

Hi folks !

The recommended RCD can be found in the integration manual for a specific controller generation / robot.

It is also dependent on the size of the cabinet.

In my case it's a 300mA version, with 3x25A and retarded action, type "Ai", "SI" , "HPI" or "F" depending on fabricator.

What I don't understand in my documentation is that it specifies a three phase RDC with no neutral.

My electricial put a 4 pole RDC (3 phases + Neutral), and I have no idea if the Neutral is grounded.

The X1 wiring schematic marks the Neutral as an "Option for service socket".

I have no idea what that means.

In short, I'd like to know what to do with the damn Neutral lead...

it is exactly as described. KRC4 does NOT use neutral.

but if you want to add an OPTIONAL service receptacle (230VAC single phase outlet) so that service technician can plug his laptop or phone charger or whatever, then you DO want the N wired as well.in most of the world three phase supply is 400VAC phase to phase. but that also means that phase to neutral is 230V.

if you are in Americas and use NA version of the controller, those units do not use Neutral conductor. This is because they use transformer and 120VAC output is obtained from single phase secondary (500VA max)..

Got It. I'll just unplug the Neutral.

What worries me is all that fuss about the "neutral having to be grounded".

If Neutral isn't plugged in X1, what difference would it make if it wasn't grounded ?

As I mentionned, I experienced first hand that the neutral and the ground are NOT at the same potential in my workshop because I tripped the RCD when cutting a 220V single phase wire.

I'm sure that the switch was off, so the phase wasn't "hot".

I even came to wonder if that's why one of my KSPs went bad...

Quote from Wall-E

.. I even came to wonder if that's why one of my KSPs went bad..

No. As you see, neutral isn't used inside the cabinet of the Kuka, so it can't be a problem if you connect it to the x1. The wire ends there

Quote from Wall-E

I tripped the RCD when cutting a 220V single phase wire.

How did you do that exactly? Did you use an unisolated cutter?? Or did you cut a 3 wire cable with one cut?

Read the spec. Spec is not written for Germany or France only. It is universal and shall be followed everywhere around the world

Grounded neutral is grounded at the supply... By grounding center of the WYE (secondary of the supply) you are ensuring to meet another KRC spec requirement - all phases are balanced or symmetrical about neutral or ground. Some places have unusual supply with corner grounded delta. This is not compatible with KRC and requires isolation transformer. Your electrician should know know all this.

Quote from hermann

How did you do that exactly? Did you use an unisolated cutter?? Or did you cut a 3 wire cable with one cut?

Yes, I'm a morron. I cut the three cables at once. But as I said, the phase was out, so the short came from connecting earth and neutral.

Quote from panic mode

Grounded neutral is grounded at the supply... By grounding center of the WYE (secondary of the supply) you are ensuring to meet another KRC spec requirement - all phases are balanced or symmetrical about neutral or ground. Some places have unusual supply with corner grounded delta. This is not compatible with KRC and requires isolation transformer. Your electrician should know know all this.

The Electrician told me that in France, Earth and Neutral are grounded by the utility.

It is forbidden to do it in your own installation.

He told me that sometimes, there car ne a slight potential difference because between the source and the plug, there can be induced currents in the Earth and Neutral ; this is what tripped my RCD when I cut my cables.

But I have no idea if this is a problem for my Robot. I might be worrying for nothing, but it still isn't a clear-cut case for me.

As per my electrician, he probably isn't the sharpest tool in the shed. He put a local "D" curve RCD for my dedicated robot line, but left a standard main RCD for the workshop. Now the latter is tripping each time I shut the controller

Then the behaviour is normal. When you cut the wire neutral and earth is connected and build a parallel resistor with a very small value, but never the less a small current will go through the earth line because there always exist a very small potential difference between earth and neutral, when other devices are connected on the same fuse (not the RCD).

Edit: The robot has no problem with the neutral, he doesn't use it. It is not wired inside the cabinet.

If RCD are cascaded they must be selective, see: https://www.electrical-installation.org/enwiki/Coordin…tective_devices

In your installation they are selective, but the wrong way

Quote from hermann

In your installation they are selective, but the wrong way

Yep, I guess that sums it up nicely.

Thanks Hermann !