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4.2.2
Reversing or Non-Reversing Starter
The EMR-3MP0 uses the phase currents to calculate the symmetrical components
(positive and negative system). Based on these the EMR-3MP0 determines the phase
rotation of the applied system. If the measurements fit to the setting [System
Para] »Phase Sequence«, the signal »MStart . RFD_IA_Normal« is set; otherwise the
signal »MStart . RFD_IA_Reverse« is set.
The setting [System Para] »Reversing« specifies whether or not the starter for this motor
is designed to reverse the phase sequence and to make the motor run in either direction.
The setting value »Reversing« = “Active” specifies that a motor start with reversed phase
sequence is an acceptable operating condition. In this case the EMR-3MP0 accepts either
sequence at the time of a start. The calculated symmetrical components (positive and
negative system) get exchanged automatically if the reversed situation is recognized, and
all protection functions that are based on these measurements continue without getting
alarmed.
The setting value »Reversing« = “Inactive” specifies that a motor start with reversed
phase sequence is not an acceptable operating condition. In this case
the »MStart« module trips and sets the following signals approximately 100 ms after the
motor has been started:
• »MStart . TripPhaseReverse«
• »MStart . Trip«
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EMR-3MP0
4 Protective Elements
4.2 Motor Starting and Control Module