Eaton Digitrip RMS Series Instructional Leaflet

Also see for Cutler-Hammer Digitrip RMS 510: Instructions Instructions Instruction leaflet

Figure 7 BYZ Zero-Sequence Current SensorAs the breaker opens, the left pole unit lever pin strikesthe spring finger attached to the reset lever; this furnishesthe assistance required to move the disc so as to close theair gap between it and the permanent magnet against thespring force.The device is reset when the disc is in contact with themagnet. If the gap is not fully reset, the trip shaft lever willhold the breaker mechanism in the trip-free condition andthe breaker cannot be re-closed.The trip actuator must be replaced, if it will not stay reset,when the plunger has been moved to the top of its travel.5.4 Ground Fault ProtectionWhen the Digitrip Trip Assembly includes ground fault pro-tection, the distribution system characteristics, i.e., systemgrounding, number of sources, number and location ofground points, etc. must be considered as well as the man-ner and location in which the circuit breaker is connected tothe system.If the system neutral is grounded but the neutral is not car-ried with the phase conductors, the Digitrip Trip Assemblyincludes all of the equipment necessary for ground fault pro-tection. The basic mode of ground fault sensing employs aresidual sensing scheme which vectorially sums the outputsof the individual phase current sensors. As long as the vecto-rial sum is zero, then no ground fault exists.If the system neutral is grounded and a neutral conductoris carried with the phase conductors, it is necessary to usean additional sensor for the purpose of canceling out anyresidual current in the phase conductors. This sensor mustbe mounted separately and must be located on the neutralconductor at the point where the neutral conductor connectsto the neutral bus. These sensors are duplicates of thosesupplied on the breaker except for the 2400A and 3200A rat-ings where a modified neutral sensor is required.The adjustment of the ground fault functional settings isillustrated in the applicable Digitrip RMS and Digitrip OPTIMTrip Unit instruction leaflets referenced in Section 7.1 of thisinstruction book. Either flat response or I2t response settingsmay be selected. The effect of these settings is illustrated inthe ground fault time-current curve referenced in Section 8.2of this instruction book. Applicable residual ground fault set-tings are given in Table 3 and on the time-current curve.Effective July 2010Instructional Leaflet IL8700C39-047.88 9.906.123.063.066.124.75.530 Dia. 4-Total9.12Dimensions (in Inches)Current StyleRatio100/5 592C102G0350/5 592C102G0113eaTOn CORPORaTIOn www.eaton.com