Is a mirror contact the same as a positively driven contact?

[Gingko_Elec]

Hello,

For a safety chain on a conveyor belt line, it’s requested to have mirror contacts attached to the

Contactor that switch On and OFF the belt. Is a mirror contact the same as a positively driven contact?

Thanks for your answer

[TeSysMen · Accepted solution]

the term "positively driven contact" is used in IEC 60947-5-1 to define a mechanicaly interlock: combination of NO/NC contacts for control relays. it prevents contact to be closed/opened in case the opposite contact is welded.

the IEC 60947-4-1 standard defines the term "mirror contact" for power contactors and concerns only NC auxilliary contact that will guarantee that it cannot be closed simultaneously with an NO main power contact.

in your case you are looking for mirror contact.

[Anonymous user]

I think the confusion comes sometimes from the translation.

If we speak about the aux. contacts of Contactors (NO or NO) we speak first of all about " linked contacts" meaning probably the same as positive driven. As explained by the others the mirror contact is specifically referring to the NC contact to be used in safety circuits. :

In a TeSys D contactor that has a NO and a NC aux contact both contacts are not closed at the same time and the NC contact and the main poles are not open at the same time. They are ' linked '  to the main poles.

Take care some of our competitors don't offer these linked contacts not in there design. They often want to speak about " safety contactors"  which is a none existing term in the machine directive or the EN60294. What they mean is that they have mechanically fixed the separate aux. contacts so they cann't be removed. For customers that like the approach of a " safety contactor "  we still have the red covers which makes it a visual part of a safety chain. Our contactors offer maximum safety from its design. There is a TVDE/TuV certificate to proof it.

Customers are often using the term " mechanical forced contacts " when they mean linked contacts. An aux contact of a contactor is never forced. Forced contacts can be recognized by an horizontal arrow in a circle. Examples of forced contacts are pushbutton contacts and limit switches. They are  forced open either by your finger or by an object in case of a limit-switch.

Of course these components are also part of a safety chain

Schneider is the supplier when it comes on safety solutions :

- Safety Control with e-stops and pull wire switches

- Safety Detections with limit-switches, coded switches, key-switches, light curtains

- Safety Monitoring with safety-relays, safety-controllers and safety plc.

- Safety in installation stop by Freq. converters with or without DC breaking, Circuit-breakers, Contactors, Vario type switches.

- Safety Visualisation with all the Signalling components from pilot lights to beacons, flashing lights and sirens.