Solid-State Operating Mechanism For Standard Contactors With Remaining Lifetime Signal Rlt - Siemens SIRIUS 3RT Manual

6.3 Operating mechanism system / coil selection 3RT contactors and 3RH2 contactor relays
6.3.2.3 Solid-state operating mechanism for standard contactors with remaining lifetime signal
RLT
Remaining lifetime signal (RLT)
For the 3RT10 and 3RT14 air-break contactors, there are electronically controlled solenoid
operating mechanisms alternatively referred to as the "remaining lifetime signal RLT"
feature. The RLT function detects main contact erosion and provides visual and electrical
indication of a pending contact change by the plant operator.
Function
Main contactor contacts are working parts and must be replaced in good time when the end
of their service life has been reached. The degree of contact erosion and thus the electrical
endurance (= number of operating cycles) depends on the loading, utilization category,
operating mode, etc. Routine checks / visual inspections by maintenance personnel are
needed in order to monitor the state of the main contacts. The "remaining lifetime signal"
device takes over this task. It does not count the number of operating cycles (this does not
provide information about contact erosion) but instead electronically identifies, evaluates and
stores the actual progress of erosion of each one of the 3 main contacts, and outputs a
warning when specified limits are reached. The stored data are not lost if the control voltage
fails.
After replacement of the main contacts, measurement of the remaining lifetime must be reset
using the "RESET" button, and then begins anew.
Alarm signals
Signaling takes place via a floating relay contact when a remaining lifetime of 20 % is
reached, in other words, when the contact material is 80 % worn and replacement of the
main contacts must be arranged.
The different contact erosion states are also indicated visually on the laterally mounted
electronic module of the contactor via LEDs:
● 60 % with remaining lifetime (green LED)
● 40 % (orange)
● 20 % (red)
SIRIUS - SIRIUS 3RT Contactors/Contactor assemblies
Manual, 09/2017, A5E03656507120A/RS-AE/006
Configuration
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