Eaton S611 User Manual

Also see for S611: Installation leaflet Quick start installation guide Installation leaflet

Contents

S611 Soft Starter MN03902011E—May 2012 www.eaton.com 17Functional DescriptionPowerThe S611 soft starter controls the voltage applied to athree-phase induction motor in order to control the startingtorque and provide a smooth starting characteristic. Withinthe soft starter are three power poles, each of whichincludes a set of anti-parallel SCRs (thyristors) in parallel witha contact. During a start, the conduction periods of the SCRsare continuously adjusted to apply a gradually increasingvoltage to the motor, resulting in gradually increasing torqueand a smooth start. As the motor reaches its rated speed,the power pole contacts are closed, bypassing the SCRs forthe most efficient operation.Line Connected Soft Starter SCRsFor each start, the length of time the SCRs are conductingcurrent as well as the magnitude of that current determinehow hot the SCRs will get. Between successive starts, theSCRs must cool down to avoid exceeding their thermallimits. Appendix C—Ratings, Cooling and Power Lossesgives the S611’s application ratings for various startingconditions. Staying within these specified limits should avoidover temperature trips.ControlThere are four (4) terminal blocks and one (1) connector onthe face of the S611 soft starter that are used for controlcircuit functions:1. 120 Vac supply voltage (TB1)—Soft starter control powerinput.2. 120 Vac control inputs (TB2)—Remote (network) select,permissive, start, and reset control functions.3. Relay contact terminals (TB3)—One (1) Form A relay,one (1) Form C relay.4. Network communications (TB4)—Modbus connection.5. Network communications (TB5) (connector)—Connections to network adapter modules.Note: Do not apply 120 Vac to the network communicationsterminal block. 120 Vac will permanently destroy theprinted circuit board.The software contained in the S611 soft starter is the heartof the product. This software allows you to control nearlyevery aspect of the soft starter’s functionality. In this section,various features and protection options are described.Note: You will find a complete listing of these parameters inAppendix A—Parameters.L3MotorThree-PhaseAC LineVoltageL2L1T3T2T1www.comoso.com