Eaton SBN-508 Instructions For Installation, Operation And Maintenance

Also see for Magnum SB Series: Technical product guide

Contents

22Instructions for Installation, OperatiMaintenance of Magnum SB InsulatedLow V oltage Power Circuit BreakeEATON CORPORATION www.eaton.comInstructional Leaflet IB2C12063H03Effective March 2012Operating MechanismThe Magnum SB operating mechanism is based on the provencam and spring design of the DSII power circuit breaker It iseasily accessed by removing four cover screws and the frontcover (Figure 27) The mechanism is a two-step stored energymechanism Potential energy is stored to close the circuitbreaker Sufficient energy to open the circuit breaker remainsavailable after a closing operationManual OperationOn manually operated circuit breakers, the closing spring canonly be charged manually To manually charge the spring, insertone finger in the recess behind the charging handle and pullout This permits a gloved hand to grasp the handle and begincharging (Figure 28) It takes from 5 to 7 downward strokes onthe charging handle to complete the manual charging processIt is possible to manually recharge the spring immediately afterclosing the circuit breaker and before it has been tripped openStandard manually operated circuit breakers are closed andopened by hand using the Manual “ON” and Manual “OFF”buttons respectively located on the front of the circuit breaker(Figure 20) Performing either operation is accomplishedby pressing and releasing the appropriate button Access tothese pushbuttons can be limited by the use of an optional,padlockable cover In addition, complete access to the “ON”button can be prevented with an optional prevent close coverThe status of the springs and the primary contacts are alwaysindicated in an indicator window just above the pushbuttonsElectrically operated optional devices are available toautomatically close or trip a manually operated circuit breakerAn electrical spring release is available to close a manuallyoperated circuit breaker Two optional devices, a shunt tripand an undervoltage release, are available to automaticallytrip (open) a manually operated circuit breaker All of these ULlisted optional devices can be installed easily in the field Formore details on these devices, refer to “Accessory Devices” onpage 48 of this manualAn electrical operator which is used to charge the closingspring automatically can be added to a manually operatedcircuit breaker in the field (Figure 29) Manually operated circuitbreakers are pre-wired to accept this addition1 Secondary Wiring Points2 Field Installable Accessories (3 maximum)3 Trip Unit4 Electric Charging Motor5 Manual Charge Handle6 Operations Counter (optional)7 Padlockable Levering Device Access Door8 Breaker Position IndicatorFigure 27. Typical Electrically Operated Drawout Circuit Breaker with Front Cover Removed