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 135 page image

1356.1.4. Cumulative start-up time counterThe cumulative start-up time counter functions as backup to the thermal overloadprotection and prevents too frequent motor start ups, i.e. ensures that therecommendations from the manufacturer are followed.There are two values to set: the restart disable value in seconds, 66, and thecountdown rate of the start-up time counter, 66 COOL/Δt.The restart disable value is calculated as follows:66 1= − × +( )n t margin (11)n = allowed number of motor start upst = start-up time of the motor (in seconds)margin = safety margin (~10... 20%)The countdown rate is calculated as follows:66COOL tt reset= (12)t = start-up time of the motor (in seconds)treset = time during which the maximum number ofmotor start ups stated by the manufacturer can bemade (in hours)If the motor manufacturer has recommended a maximum of three start ups in fourhours and a start-up time of 60 seconds/start up, the restart disable will be activatedwhen the third motor start up has been initiated, thus preventing a fourth motor startup. Consequently, the restart disable value is to be set to 130 seconds.A maximum of three motor start ups in four hours means that the register’s valueshould reach the set restart disable value four hours later to allow a new motor startup. Consequently, the register’s value should decrease by 60 seconds in four hours,i.e. 66 Cool / Δ = 60 s/4h = 15 s/h.6.1.5. Short-circuit protectionIt is recommended that the set pickup value of element 50P is set to be automaticallydoubled during motor start up. Consequently, a pickup value lower than the start-upcurrent of the motor can be selected.A pickup value of 70%...90% x the start-up current of the motor is normallyselected. This low a set pickup value together with a suitable set operate time willenable tripping of the high-set overcurrent element if overcurrent due to a lockedrotor, for instance, is detected while the motor is running.Motor Protection RelayTechnical Reference Manual - ANSI VersionREM 610REM 6101MRS755537