Yes, it's an old ASEA time-overcurrent relay designed 1918 by Waldemar Petersen (1880-1946). He's the farther of Petersen coil, too. This relay had an extemely long life span of 65 years: 1920 - 1985.
At least ABB and VAMP have still this RI-characteristics in their modern relays.
The RI-characteristics is nowadays defined mathematically. You can find the equation for example from
Support ...
Product documentation ...
Power generation ...
VAMP 210 generator protection relay ...
User's manual v005.
PDF page number 136 has the RI equation.
ABB was created 1987, when ASEA and BBC went together, so you could ask more details from ABB Finland.
Hi.
If we back to this relay.
RI-curves.
t(s)= k (0.339-0.236xI>/I).
k= 0.05--1.
I>, set point.
In new relay used for time grading with EM relays.
ABB Finland digital relays , in past Stromber, Vaasa.
Regards.
Slava
At the time when I posted this a few days ago, I thought it was an R1 relay. After spending time researching and finding nothing, it then occured to me as I glaced at the photo in baffle... Wait a minute, that might be an I, as an RI, not R1!
Once I googled Abb RI relay, it all come out.
As you guys mentioned:
The RI curve is an ABB characteristic curve that is still included in some of their modern relays. IE ABB's SPAJ140, the RI equations can be found on pg 19 of the SPAJ140 manual and the curves are shown on page 24.
Slavag, I see you posted the eqn on this thread. I want to say thank you for taking the time to help me out.
What's good is that many of the ABB model's in ETAP also have the RI curve.
Again, you guys mentioned it dead on, but for reference material (if anyone wants it) here is ome historical info on this relay available at ABB website:
