Eaton Cutler-Hammer RMS 510 Instructions Manual

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

I.L. 29-885BPage 4Fig. 2.5 Long Time/Short Time/Ground/Protection(LSG)Fig. 2.6 Long Time/Short Time/Instantaneous/GroundProtection (LSIG)The Digitrip RMS 510 Trip unit provides three basic func-tions: Protection, Information and Testing. Atypical tripunit and rating plug are illustrated in Fig. 1. Individualproduct instruction leaflets referenced in Section 9.0 illus-trate typical Digitrip RMS Trip Units installed in specificbreakers.The trip unit employs the Cutler-Hammer Inc. customdesigned integrated circuit S|.iRE + chip, which includesa microcomputer to perform its numeric and logic func-tions. The principle of operation is described by the blockdiagram shown in Fig. 3.In the Digitrip RMS 510 Trip Unit, all required sensingand tripping power to operate its protection function isderived from the current sensors in the circuit breaker.The secondary currents from these sensors provide thecorrect input information for the protection functions, aswell as tripping power, whenever the circuit breaker iscarrying current. These current signals develop analogvoltages across the appropriate calibrating resistorsincluding:1) Phase currents2) Ground current (when supplied)3) Rating plugThe resulting analog voltages are digitized by the customdesigned integrated circuits.1.3 TestingTo test the trip unit, use the integral test panel. (See Sec-tion 5.0.)2.0 UL LISTED DEVICESDigitrip RMS 510 Trip Units are “Listed” by the Underwrit-ers Laboratories, Inc.® Under UL File E7819, for use intypes DS, DSL, SPB and Series C® R-Frame circuitbreakers.3.0 PRINCIPLES OF OPERATION3.1 GeneralThe Digitrip RMS 510 trip unit is designed for use inindustrial circuit breaker environments where the ambienttemperatures can range from -20 C to +85 C and rarelyexceed 70 to 75 C. If, however, temperatures in theneighborhood of the trip unit do exceed this range, thetrip unit performance may be degraded. In order to insurethat the tripping function is not compromised due to anover-temperature condition, the Digitrip RMS 510 micro-computer chip has a built-in over-temperature protectionfeature, factory set to trip the breaker if the chip tempera-ture exceeds 95 C. If over-temperature is the reason forthe trip, the Long Delay Time LED will light “RED”.Effective May 1997