SIRIUS Soft Starters - Siemens

SIRIUS 3RW44 – for soft starting ofmilling machines with DC brakingThe SIRIUS 3RW40 offers thissensitivity as a standard■ The settable current limiting of theSIRIUS 3RW40 limits the load of themains transformer during motorstart-up.■ Motor protection is ensured by themotor overload relay with settabletrip classes integrated in the softstarter.■ The adjustable voltage ramp ensuresthe hydraulic pump’s start and stopwithout torque surges.For the production of motor blocks, therequired bores are drilled in the motor’saluminum block by means of a millinghead. Due to the milling head’s highinertia, shutdown of the 15-kW motoris subject to long stopping times, whichcause long downtimes for tool changesand set-up operation.The start-up behavior of millingmachines requires maximumfunctionality■ To prevent excessive wear of the drivebelts due to slippage, milling machinesrequire an optimized and torque-controlledstart-up behavior.■ The motor’s starting current has to bereduced to minimize the mains load.■ The motor has to be braked with DCcurrent to reduce the machine’s longstopping times.Competent solution with SIRIUS 3RW44■ To optimally master the difficultstarting conditions, the SIRIUS 3RW44with torque control and dynamic DCbrake function is employed.■ Slippage of the belts during start-up isprevented by torque control with adjustedtorque limiting function.■ This rapidly accelerates the millinghead to the nominal speed withoutslippage of the belt drives.■ A higher-level current limiting functionreduces the motor’s starting current toa set maximum value.■ The optimum setting of the dynamicDC brake function shuts the millinghead down in minimum time.■ Also motor and device overloadprotection is excellently mastered bythe SIRIUS 3RW44 high-feature softstarter.21