Positively Driven Contact Elements/Mirror Contacts - Siemens SIRIUS 3RT Manual

Standards

2.3 Positively driven contact elements/Mirror contacts

2.3 Positively driven contact elements/Mirror contacts
Positively driven contacts for contactor relays according to IEC 60947-5-1
Positively-driven contact elements according to IEC 60947-5-1 are a combination of "n" NO
contacts and "m" NC contacts which are designed in such a way that they cannot be closed
simultaneously. "Positively driven operation" may only apply to auxiliary switch elements
which are contained in switching devices and whose actuating forces are generated
internally. An example of such elements are the SIRIUS 3RH2 contactor relays.
All SIRIUS 3RH2 contactor relays (with at least 1 NC contact) are tested to IEC 60947-5-1,
and ever since the product was launched, they have featured positively driven contact
elements in the basic device, or in the basic device in conjunction with auxiliary switches.
Figure 2-1
Mirror contact for power contactors to IEC 60947-4-1
A mirror contact according to IEC 60947-4-1 is an auxiliary NC contact that cannot be closed
simultaneously with an NO main contact.
Figure 2-2
All SIRIUS 3RT1 / 3RT2 motor contactors (with at least 1 NC auxiliary contact) are tested to
IEC 60947-4-1 and have featured mirror contact characteristics in conjunction with auxiliary
switches ever since the product was launched.
Note
Both contact characteristics, the positively driven contact element in the contactor relay as
well as the mirror contact in the power contactor, meet the same technical requirements.
The 3RT1 / 3RT2 / 3RH2 contactors are suitable for applications in the safety circuit. For
contactor relays, this applies on account of the positively driven operation of the contacts.
For motor contactors, it applies on account of the mirror contact properties of the auxiliary
contacts.
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Symbol for positively driven contact elements in a switching device
Symbol for mirror contacts in a switching device
SIRIUS - SIRIUS 3RT Contactors/Contactor assemblies
Manual, 09/2017, A5E03656507120A/RS-AE/006