Time curves for Siemens ETU745 & 766

[Dave32]

We are needing to do primary injecting testing on some Siemens WL breakers with an ETU745 & 766 trip unit. I have searched the internet and I can’t seem to find any curves for the units.

Also, I think to override the ground fault I need to jump pins 9 & 10 on 8X?

Any help would be appreciated.


Thanks
Dave.

[SecondGen]

We are needing to do primary injecting testing on some Siemens WL breakers with an ETU745 & 766 trip unit. I have searched the internet and I can’t seem to find any curves for the units.

Also, I think to override the ground fault I need to jump pins 9 & 10 on 8X?

Any help would be appreciated.


Thanks
Dave.

For that trip unit, I think you need to download the Siemens Time Current Curve (TCC) Software. Once installed, you can fill out the breaker info and trip unit settings and it will generate the curve for you.

http://w3.usa.siemens.com/powerdistr...-software.aspx

You might find the software a bit difficult to use, its outdated and not designed very well. As for ground fault, if I remember correctly on that trip unit you need to change the ground fault sensing scheme to source ground when primary injection testing, this looks at current on the neutral sensor only.

I'm having trouble finding the specific manual for you trip unit. Some models have a switch, others have a jumper that can only be changed by removing the trip unit.

[Kalbi_Rob]

We are needing to do primary injecting testing on some Siemens WL breakers with an ETU745 & 766 trip unit. I have searched the internet and I can’t seem to find any curves for the units.

Also, I think to override the ground fault I need to jump pins 9 & 10 on 8X?

Any help would be appreciated.


Thanks
Dave.

This is the manual that answers your question, a little late, but good for anybody else:

https://docs.natlswgr.com/docs/W1000570.pdf

[oarreola]

What do you use to power up a ETU 776 trip unit out of the cubicle?

[Kalbi_Rob]

What do you use to power up a ETU 776 trip unit out of the cubicle?

If I remember right (its been years since I had to do this), you can supply 24Vdc to X8 terminals 3(+) and 4(-). That being said, you need to verify you have a true filtered dc power supply, or it can fry the ETU trip unit.

[oarreola]

If I remember right (its been years since I had to do this), you can supply 24Vdc to X8 terminals 3(+) and 4(-). That being said, you need to verify you have a true filtered dc power supply, or it can fry the ETU trip unit.

What would be the best way to filter the dc supply?

[Kalbi_Rob]

What would be the best way to filter the dc supply?

If your power supply has a DC regulator, it will have a pure DC output. If your using a power supply that uses a bridge rectifier with a capacitor, it could produce a ripple DC output. A ripple DC output can be used, but if the capacitor starts to fail, the ripple can become larger and damage sensitive DC equipment.

Thus, you need to know what kind of power supply you have based on manufacturer drawings. If you don't know, then your better off using the Siemens secondary kit, or powering up the switchboard CPT which powers up the equipment DC power supply.

[SecondGen]

What do you use to power up a ETU 776 trip unit out of the cubicle?

Siemens Secondary Kit, would recommend renting if you don't need it often.

[oarreola]

Thanks guys!

[AaronCBI]

I just performed primary injection testing on a WL type Siemens breaker with a ETU 745 trip unit.
The only way that I know of to obtain the time current curve is with their (Siemens) curve plotting software, Easy TCC.