Eaton NRX Instruction Manual

Also see for NRX: Installation instructions

17Section 4: Circuit breaker features and accessoriesSeries NRX with PXR - type RF low voltage power (air) circuit breakers instruction manual MN013002ENH03 September 2016 www.eaton.comFigure 28. Installed PXR trip unit.Table 2. Series NRX trip units.Functions PXR20 PXR 25LSIG protection Yes YesDisable (I) Yes YesGF protection Option OptionGF alarm Option OptionDisplay Yes YesProgrammable No NoCurrent metering Yes YesPower/energy metering No YesPower quality metering No NoCommunication Yes YesRating plugA rating plug is not required with PXR trip units. See framerating module description.Current sensorsRogowski coil type current sensors are installed on theload terminals at the bottom rear of the circuit breaker. Thesensors furnish the trip unit with a signal and the energyrequired to trip the circuit breaker.An external neutral current sensor is available for customerinstallation, and must be ordered separately.Frame rating moduleThe PXR frame rating module is mounted just behind thetrip unit and stores data related to the breaker’s ratings(including the maximum continuous RMS current), manufac-turing information, and health of the breaker frame.The interchangeable trip unit attaches to the permanentframe rating module. Since the PXR trip unit no longerrequires a fixed type rating plug, the continuous current (In)rating is factory programmed in the frame rating module.The programmed value of I n is shown on the trip unit’sLCD display and printed on the Battery cover at the lowerright corner of the trip unit. The In rating displayed and pro-grammed will be equal to or less than the breaker frame’smaximum rated current as listed on the nameplate inFigure 1.The breaker’s I n rating can be re-programmed by interfac-ing with the USB port on the trip unit. Please contact yourEaton sales representative for details on proper re-program-ming of the trip unit.Frame rating modules installed on series NRX air cir-cuit breakers with PXR are permanent and SHOULDNEVER BE REMOVED. The frame rating module batterycover with printed In rating (see Figure 7) should not bechanged without proper reprogramming of the trip unit.The In rating programmed from the factory is displayedin the lower left hand corner of the LCD screen when-ever power is applied to the trip unit. The In displayedon the LCD reflects the actual In rating of the breaker,while the value on the battery cover is for reference onlywhen the LCD is not powered. The In rating displayedon the LCD screen and In rating printed on the framerating module battery cover MUST ALWAYS AGREE.See MN013003EN for more information.Trip actuatorThe low-energy trip actuator is a small electromagneticdevice that provides the necessary mechanical force to initi-ate the tripping action of the circuit breaker. The electronictrip unit provides a pulse to the coil of the trip actuator,allowing the mechanical tripping action to take place. Thetrip actuator is reset by the operating mechanism.Fixed high instantaneous non-adjustable tripSeries NRX circuit breakers have a fixed instantaneousnon-adjustable setting. This fixed instantaneous trip willinitiate a trip at a high current peak which depends on thecircuit breaker type and rating. This setting is always active,regardless of the instantaneous setting.Non-automatic deviceSeries NRX is available in a non-automatic configuration. Itis derived from the corresponding NRX automatic breakerbut does not include the trip unit, Rogowski coil type cur-rent sensors, and the high instantaneous trip feature. Theoverall dimensions and the capability of mounting mostaccessory items are maintained. Non-automatic deviceare tested in keeping with UL489 and IEC 60947-2 require-ments.