ABB REM 610 Technical Reference Manual

Also see for REM 610: Operator's manual Product guide Installation manual Product guide Technical reference manual

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ABB REM 610 Technical Reference Manual Manual pdf 38 page image

characteristic by setting the operate time to the minimum, i.e. 0.05 s. The elementwill be reset in 50 ms after all three phase currents have fallen below the set pickupvalue of the element.The set pickup value of element 50P can be set to be automatically doubled in amotor start-up situation, i.e. when the object to be protected is being connected to anetwork. Consequently, a set pickup value below the connection inrush current levelcan be selected for the element. In this case, the short-circuit protection will stilldetect overcurrent caused by a locked rotor when the motor is running, which in turnmay be caused by bearing failure, for instance. The selection is made in SGF3.When automatic doubling is in use and the FLA secondary has been setto be very low, it must be assured that the doubled set pickup value ofelement 50P does not exceed the maximum measured current.If the FLA secondary is set to 0.5, the maximum measured current is25 x full load current of the motor.It is possible to block the tripping of the high-set overcurrent elementby applying a digital input signal to the relay.The high-set overcurrent element can be set out of operation in SGF3to prevent the contactor in a contactor controlled drive from operatingat too high phase currents. This state will be indicated by dashes on theLCD and by “999” when the set pickup value is read via serialcommunication.When element 50P pickups during motor start up, no pickup signal willbe generated.5.1.4.5. Undercurrent protectionThe non-directional undercurrent protection detects loss of load, caused by adamaged pump or a broken conveyor, for instance, and can be used in applicationswhere undercurrent is considered a fault condition.When all three phase currents fall below the set pickup value of element 37, theelement will generate a pickup signal after a ~ 300 ms’ pickup time. When the setoperate time elapses, the element will generate a trip signal. To avoid tripping a de-energized motor, element 37 will be set out of operation when all phase currents fallbelow twelve per cent of the FLA of the motor.The undercurrent element will be reset in 350 ms after one or several phase currentshave exceeded the set pickup value of the element.38REM 610REM 610 Motor Protection RelayTechnical Reference Manual - ANSI Version1MRS755537