SINAMICS S120 Functi.. - Gregbotos.com

Extended FunctionsBypass (vector)4.25 Bypass (vector)FeaturesAvailable for the vector modeAvailable for induction motors without encoderDescriptionThe bypass function controls two contactors via digital outputs of the drive converterand evaluates the feedback signals of the contactors via digital inputs (e.g.via TM31). This circuit allows the motor to either be fed from the drive converter orconnected directly to the supply line. The drive converter controls the contactors;the feedback signals for the contactor states must be fed back to the drive converter.This bypass circuit can be implemented in two ways: Without synchronizing the motor to the line supply and Synchronizing the motor to the line supply.For all bypass versions, the following applies:The bypass is always switched-out when one of the control word signals“OFF2” or “OFF3” is withdrawn.Exception:When required, the bypass switch can be interlocked by a higher-level controlso that the drive converter can be completely powered-down (i.e. including thecontrol electronics) while the motor is operated from the line supply.The contactor interlocking should be implemented on the plant/system side.When the drive converter restarts after POWER OFF, the state of the bypasscontactors is evaluated. This means that after running-up, the drive convertercan directly change into the standby mode. This is only possible if the bypass isactivated using a control signal (p1267.0 = 1, p1267.1 = 0, p1267.2 = 0) and thecontrol signal (p1266) is still present after the drive has ramped-up.A changeover of the drive converter into the standby mode after the drive hasramped-up has a higher priority than the automatic restart.The motor temperatures are monitored using temperature sensors while thedrive converter is only of the two standby modes.The two motor contactors must be designed for switching under load.RequirementsThe bypass function is only possible for sensorless close-loop speed control(p1300 = 20) or V/f control (p1300 = 0...19) and when an induction motor is used.A VSM10 must be used for synchronizing with overlap.© Siemens AG 2006 All Rights ReservedSINAMICS S120 Function Manual, 03/2006 Edition4-277