Shunt trip coil controlled by electronic protection unit

[MikiBg]

Hi all.
There is ABB Sace Emax 2.2N circuit breaker with Ekip dip LI electronic protection unit. It contains a terminal for connection of control voltage to shunt trip coil via NO contact controlled by protection unit. Since protection unit must cause CB to be opened in the case of fault regardlessly of trip coil presence (installed or not), what is the purpose of this control circuit? Is it just additional safety measure for fault current interruption, or some other utilisation of this feature is foreseen?

 

[jfpe]

MikiBg,
We use the shunt trip breakers for equipment interlock or to have remote breaker open capability.
-JFPE

 

[MikiBg]

Yes, that's why I am asking. In this way CB will not be controlled remotelly, but locally by protection unit providing control voltage to shunt trip coil.

 

[davidbeach]

If there's no trip coil, the external relay won't do anything. The internal trip unit will always trip the breaker.

 

[jraef]

I think what you are seeing is that your breaker has an ETU that acts on a shunt trip internally, and they give you access to that shunt trip if you want to use it for something else.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[MikiBg]

Mystery solved by browsing other files. A terminal I was referring to serves for connection of control voltage to additional (optional) module which can be controlled remotely by communication interface. This module acts on shunt trip coil. Of course, there is another terminal for traditional, hardwired excitation of trip coil directly.
Confusion has been mainly done by catalog explaining function of questionable circuit as "opening coil with control from protection trip unit". Poor and confusing documentation given by ABB in my opinion.
Thank you all for participation.