Voltage drop on the 7i80 from e-stop contactors

When the e-stop contactors which powers the servos and spindle are turned on I get a large voltage dip that causes the 7i80 to fail and I have to restart linuxcnc to get it running again.

There is a big 200v transformer that powers the hole machine and from this a 5v 10A meanwell power supply that powers the 7i80 and I can see on my oscilloscope that the voltage drops down to 2.4v and up to 6v when I turn on and of the contactors.

I have tried the following things with no succes.
1: EMC filter on the 200v power to the 5v supply (no noticable effect)
2: Small capacitor near the 7i80 (small effect)
3: Big 10000uf capacitor near the 7i80 (a little better, max drop down to 3v)
4: Diod and then capacitor to keep the capacitors effect only to the 7i80 (no better effect and voltage drop from the diod)

What I have not tried is some kind of inductor in series with the 5v supply, I dont have much experience with that?

More suggestions anyone?

if the 5V power drops enough to reset the 7I80, this is not really a noise issue, this is a loss of power

Does the Meanwell power supply lose primary power when this happens?

Maybe you have a bad 5V supply (the output going to 6V suggests this and is a bit scary)

There is a major shift up and down in the main power also which yes is the cause of the loss in power on the 5v and 24v supplies.
There is also a quite large transformer that is powered up when the contactors are activated.
Both the 24v and 5v supply has this spike and even when I added a 10000uf capacitor it can not keep it to 5v.

The contactor coils are driven from 230v by a safety relay soo they should not cause anything directly to the 24v or 5v supply.

if your mains input power is dropping , then solve that first , this would suggest the mains wiring is not correct , or undersized
poor breaker contacts etc , or the distribution power is flakey at least .

looking at the machine to solve a mains problem will never work ,

I'll second that. I had to replace the overhead line from the meter to my house a few years ago. Large chunks of insulation missing, and the aluminum conductors rotted, and eroded away to almost nothing. It was amazing it worked at all (and no wonder my electric bills were so high.)

Sorry, I meant that the 200vac from the very large transformer also drops, not the main 400v supply, but I have not checked if that drops to so I will do that.
The machine is powered with 400v ( as is our mains here in Sweden) and transformed dowm with a 50x50x50cm transformer to 200v.

You are right, it is a mains problem so it will probably go away when the machine is installed correctly where its supposed to be.
Thanks for the help!