radar
Quote
By the way, it's still common to see large banks of relays in the field of train coltrol - not exactly the same as a relay computer but I've wondered why they haven't gone over to PLC's long ago.

I think reliabilty issues and galvanic separation are the issues here.

We use relays in all our substations for the controls eventhough the protection can be electronically, like the SEL or Siemens relays.
The outputs are relay controlled.


Edited for typo's Ray


[This message has been edited by RODALCO (edited 02-21-2006).]

The product of rotation, excitation and flux produces electricty.