Safety Terminology

[CEDEng]

More random information request. Again, I have foraged thoroughly through mounds of info, and I just don't know why folks make the obvious so doggone hard to locate.

Does anyone have a list of abbreviations relevant to safety relays, safety circuits, and the like?

For instance, "KM1" is generically a magnetic contactor - but WHY is the abbreviation KM? CMR comes to mind...

As always, thanks for the info.

 

[GoldDigger]

Maybe K is for Kontakt or Kontaktor in German?

 

[CEDEng]

I kompletely agree that's probably where it originates - but I need some real evidence.

Once upon a time I saw a glossary of these things, but I cannot find it...

 

[Jraef]

Maybe K is for Kontakt or Kontaktor in German?

Closer to the truth.

"K" is an IEC designated symbol for a contact or coil of a contactor, "M" would often be added to indicate that it is a contactor used in a Motor Starter circuit, but not always. But it does indeed come from German because many of the IEC terms were adopted from the original German standards known as DIN (Deutsches Institut f?r Normung, or German Institute for Norms, meaning standards). A contactor itself is called a "Schutz" (careful how you say that...) or a "Schalter" which is "switch" but gets used for contactors as well.

 

[Jraef]

IEC 60027 is likely where you can see the letter designations described, but it's unlikely that there will be an etymology telling where they came from.

 

[pfalcon]

IEEE Std 315 is also supporting these designations.

Appendix F "Cross-Reference List of Class Designation Letters"

Example entries:

IEC Publication 113-2 Letter Code
Terminology ................................. IEC ... Y32.2
* Cable ........................................ W ..... W
* Relay ........................................ K ..... K
@ Terminal ................................... X ..... E

Note:
* No conflict between ANSI Y32.2 and IEC.
@ ANSI Y32.2 conflicts with IEC as IEC uses class letter to represent other devices.