Woodward
Manual MRM3-2 GB
38
TD_MRM3-2_09.08_GB_Rev.New
3. Values recorded after a tripping action
•
Tripping current in Phase 1,
•
Tripping current in Phase 2,
•
Tripping current in Phase 3,
•
Tripping value for earth current E,
•
Tripping value for load-unbalance current I2,
•
Tripping value for the temperature equivalent
ϑ
in %,
•
Switch failure time,
•
Date and time.
5.11 Reset
The MRM3-2 offers the following three ways to reset the displayed indications as well as the output
relay.
•
Manual
reset
By pressing the <SELECT/RESET> push-button for some time (about 3 seconds
•
External
reset
By applying aux. voltage to C8/D8
•
Reset via interface
By transmitting the RESET command from the Master PC.
An indication can only be reset if there is no protective function activated. (Otherwise
"TRIP" remains in the display). The set parameters are not changed by the reset
procedure.
5.11.1 Erasure of the Fault Memory
For erasure of the fault memory the push-button combination <SELECT/RESET> and <-> has to
be pressed for about 3 s. During the erasure procedure „wait“ is displayed.
5.11.2 Reset of the Thermal Memory
It is possible to erase the thermal memory
ϑ
to 0%. By pressing the push-button combination
<SELECT/RESET> and <+> for some time (about 3 s) the thermal memory is reset to 0%.
IMPORTANT:
This function has to be used with extreme care. During secondary tests it can be very useful to
have always constant start conditions. If, however, after overload tripping the thermal image is re-
set in order to restart the motor as quickly as possible, then there is the risk of overloading the mo-
tor because it is still hot but the protective unit proceeds on the assumption that the motor is cold.
