Mls - Load Shedding - Eaton EMR-3MP0 Installation, Operation And Maintenance Manual

4.5 MLS – Load Shedding
Functional Description
In some applications, the protective device can forestall a JAM alarm or trip, or a thermal
trip, by sending a signal to the process to reduce loading. The load shedding function, if
enabled, closes or opens a relay contact to shed process load when the motor load
current goes above the Load Shed Drop threshold, »Dropout Threshold«, for a time
exceeding the Drop Delay, »t-Drop Delay«. This could, for example, be connected to stop
flow of material into the driven process until the load current drops below the Load Shed
Dropout threshold, for the time determined by »t-Drop Delay«.
Set the load shed pickup current comfortably below the JAM trip level. It may be useful to
set it below the Ultimate Trip Current, particularly if RTDs are not used.
The load shed function provides a contact output signal that the User connects to the
process equipment, to reduce loading on the motor if it becomes too large. For example,
the contact might be used to temporarily stop the flow of heavy materials onto a
conveyor driven by the protected motor. In this way, the protective device tries to
alleviate an overload before it reaches an outright thermal protective trip. When the load
is reduced, the contact returns to the normal state and the process can resume loading of
the motor.
The load shed function, which is active only during the RUN state of the motor, is
configured with settings within the menu branch [Protection Para / MLS].
EMR-3MP0 www.eaton.com
4 Protective Elements
4.5 MLS – Load Shedding
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