I am working on the automation of an old servo driven feed system for a mechanical power press. I have come across these relay output units from Klöckner Moeller (machine make year 1980`s) pictures added.

enter image description here.

I have a mechanical engineering background with a little know how of electronics.

  • \$\begingroup\$ You need to find techy information on it using the web/google/searches then, link it to the question. \$\endgroup\$
    – Andy aka
    Nov 11, 2020 at 16:31
  • \$\begingroup\$ Isn't there a part number on the relays? \$\endgroup\$
    – Transistor
    Nov 11, 2020 at 18:27

1 Answer 1


The best way is to use part number or model number on manufacturer website.

Relays are designed to either give dry closure or wet closure. The diagram shown seems to give both. A dry closure is one with no voltage or ground connection.

Control is the dotted line on the right. There is a diode between terminals 13 and 14, which will close on activation.


Out of curiosity, what are these connected to?

  • \$\begingroup\$ Thanks @Believer101 , They are connected to what seem to me an OLD early generation PLC by BBC(Brown Boveri and Cie). This particual relay has part number Knockler Moeller ETS 1-10. I can't find data sheet for it, just some vendors selling spares is all what i could find online. \$\endgroup\$
    – Adnan Baig
    Nov 12, 2020 at 2:24
  • \$\begingroup\$ This is an output relay. The purpose is to use a PLC output to activate the relay, which will in turn supply a signal (or dry contact) which will activate some device. Because it is polarized, the current will only flow in one direction through the contacts. \$\endgroup\$ Nov 17, 2020 at 7:55
  • \$\begingroup\$ Have you completely disassembled the previous equipment? The reason I ask is because this type of relay is usually mounted in and output relay wiring board. This is where the signals from the PLC determine what will happen. \$\endgroup\$ Nov 17, 2020 at 7:57

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