Eaton MDN-408 Instructions For Installation, Operation And Maintenance

I.B. 2C12060H08For more information visit: www.EatonElectrical.comInstruction BookEffective: May 2006Page 20ABCNGA B CN01 02 03Cutler-HammerFigure 3-17 Pictorial Diagram of Typical CurrentSensing, Processing and Tripping SystemToroidalCurrentSensorRating PlugTrip Unit TripActuatorNote: Alternate ground locationsmay be required to meetinstallation requirementsSensorsTypical Magnum DSCircuit Breaker3-6 ELECTRONIC TRIPPING SYSTEMThe Magnum DS/DSX/DSL circuit breakers utilize athree part tripping system (Figure 3-17):• Microprocessor-based trip unit• Current Sensors• Trip ActuatorAll three parts of the tripping system are discussedhere, except that the trip unit itself is not discussed indetail. For detailed information pertaining to the differ-ent trip unit models available with MagnumDS/DSX/DSL circuit breakers, refer to the specificinstruction leaflet dedicated to the trip units (I.L.70C1036 and I.L. 70C1037 ).3-6.1 MICROPROCESSOR-BASED TRIP UNITMagnum circuit breakers use any one of a family ofDigitrip RMS trip units whose main features are summa-rized in Table 3.1. Also, the MDSX family of breakers isintended to be used only with trip units manufacturedafter May 1, 2005.Models 520 is plug compatible and interchangeable inthe field. Circuit breakers with these trip units can beupgraded to Models 520M and/or 520MC in the field;however additional wiring (for power supply and com-munications) may be required to take full advantage ofthe additional features. Contact Cutler-Hammer forupgrading to Model 1150.The electronic trip units are self-powered. When the cir-cuit breaker is closed, no external power is required tooperate their protective systems. Current signal levelsand the control power are derived from the current sen-sors integrally mounted in the circuit breaker.A functional local test of a major portion of the trip unit’selectronic circuitry and the circuit breaker’s mechanicaltripping action can be verified through the trip unit’s testreceptacle (Figure 3-18). This is accomplished using aDigitrip (DS Type) Test Kit which provides a secondaryinjection test that simulates the current sensors. Asmall hand held Magnum functional Test Kit can also beused to check circuitry and mechanical tripping func-tions (Figure 3-19).When the circuit breaker is shipped from the factory, thetrip unit’s protective functions are normally set at mini-mum values. For specific overload tripping characteris-tics and time/current curves to coordinate with a load orsystem, refer to the trip unit instruction book.➀ One-line, (four characters per line) LCD display.➁ Three-line, (eight characters per line) LED display.➂ Phase, neutral, ground, and high load current only.➃ Available control voltages are 24/48Vdc, 125Vdc, 120Vac and240VacFunctions 520 520M➃ 520MC➃ 1150➃LSIG Protection Yes Yes Yes YesDisable (I) Yes Yes Yes YesGF Protection Yes Yes Yes YesGF Alarm No Yes Yes YesDisplay No Yes ➀ Yes ➀ Yes ➁Programmable No No No YesMetering No Yes ➂ Yes ➂ YesPower andEnergy Values No No No YesPower Quality No No No YesCommunication No No Yes YesTable 3.1 Magnum Digitrip Trip Unitswww . ElectricalPartManuals . com