Relay Terminal Standard Numbers

I finally did a little research to see if there was any meaning behind the numbers I often see on relays.  Of course there is!  It is European standard EN 50005.

  • NO: 3 and 4
  • NC: 1 and 2
  • Form C: 1 = common, 2 = NC, 4 = NO
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One Response to Relay Terminal Standard Numbers

  1. Tony says:

    You’re just figuring this out?! Form A -NO, Form-B NC, Form C-both. As far as I remember I was born with this knowledge.

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