the fault disappears before the module operates, the reset timer is activated. If thereset timer reaches the value of 200 ms, the operation timer resets and the STARToutput is deactivated.The timer calculates the start duration value START_DUR, which indicates thepercentage ratio of the start situation and the set operation time. The value isavailable in the monitored data view.4.4.3.5 ApplicationThe rotation of a motor in the reverse direction is not a desirable operatingcondition. When the motor drives fans and pumps, for example, and the rotationdirection is reversed due to a wrong phase sequence, the driven process can bedisturbed and the flow of the cooling air of the motor can become reversed too.With a motor designed only for a particular rotation direction, the reversed rotationdirection can lead to an inefficient cooling of the motor due to the fan design.In a motor, the value of the negative-sequence component of the phase currents isvery negligible when compared to the positive-sequence component of the currentduring a healthy operating condition of the motor. But when the motor is startedwith the phase connections in the reverse order, the magnitude of I2 is very high.So whenever the value of I2 exceeds the start value, the function detects the reverserotation direction and provides an operating signal that disconnects the motor fromthe supply.4.4.3.6 SignalsTable 371:PREVPTOC Input signalsName Type Default DescriptionI2 SIGNAL 0 Negative sequence currentBLOCK BOOLEAN 0=False Block signal for activating the blocking modeTable 372:PREVPTOC Output signalsName Type DescriptionOPERATE BOOLEAN OperateSTART BOOLEAN Start4.4.3.7 SettingsTable 373:PREVPTOC Group settingsParameter Values (Range) Unit Step Default DescriptionStart value 0.05...1.00 xIn 0.01 0.75 Start valueOperate delay time 100...60000 ms 10 100 Operate delay timeSection 4 1YHT530004D05 DProtection functions458 615 seriesTechnical Manual
