Eaton CUTLER-HAMMER MD-3000 series Installation, Operation And Maintanance

For more information visit: www.EatonElectrical.comInitial Releasedifferential overcurrent pickup set point is being viewed inthe unit’s normal operating mode. The LED will blink redwhenever the load current exceeds the differentialovercurrent pickup set point. If the relay trips on differentialovercurrent, the LED will be continuous red.Time LEDThis LED will blink green, while in the program mode,when the LED time set point is displayed in theSettings/Test Time/Trip Cause window. When the timemultiplier is being viewed in the unit’s normal operatingmode, the LED is a constant green.I A Diff, I B Diff, I C Diff LED’sThe specific phase current LED’s will be a constant greenwhen that phase differential current is being displayed inthe rms ampere window.Program LEDThis LED is a constant green when the relay is in theprogram mode.Test LEDThis LED is a constant green when the relay is in the testmode.Display Windows: Two windows are used to display therelay’s data, Set Points and messages. One window islocated in the upper portion of the relay’s faceplate and islabeled RMS Amperes. A second window is located in thelower portion of the faceplate adjacent to the program andtest LED’s. It is labeled Settings/Test Time/Trip Cause.RMS Amperes WindowThis window has a five digit numeric display and shows:1. The present phase differential currents.2. The phase current transformer CT setting (when “ViewSettings” pushbutton is used with the relay in thenormal operating mode).Settings/Test Time/Trip Cause WindowThis window is a four character alphanumeric display usedto show the value of the Set Points, the test time and thecause of trip.2-2.2 REAR ACCESS PANELTHE BACK OF MD-3000, WHEN ENERGIZED,OFFERS EXPOSURE TO LIVE PARTS WHERETHE HAZARD OF A FATAL ELECTRIC SHOCK ISPRESENT. ALWAYS DISCONNECT SOURCE ANDCONTROL POWER SUPPLY BEFORE TOUCHINGANYTHING ON THE REAR OF THE MD-3000.FAILURE TO DO SO COULD RESULT IN INJURYOR DEATH.The rear access panel of MD-3000 is normally accessiblefrom the rear of an open panel door. All wiringconnections to the MD-3000 Protective Relay are made atthe chassis’ rear. For the sake of uniform identification, theframe of reference used when discussing the rear accesspanel is facing the back of the relay. Become familiar withthe functions and connections involved, especially thefollowing:DIP Switches: A set of ten DIP switches is located in theupper left portion of the rear panel. These switches areunused in the MD-3000.Differential Trip contact (TB2 14 and 15) and the TripAlarm contact (TB2 6, 7 and 8) change state after aprotection trip operation. The contacts stay in that stateuntil the “Reset” Pushbutton is pressed. In addition, thefront panel will hold the cause of trip in the “Trip Cause”window and the fault current magnitude in the “RMSAmpere” window.Terminal Block One (TB1): TB1 is located on the left sideof the rear panel, and is numbered 1 through 15.Terminals 5 and 6 are provided for the AC or DC inputcontrol power connections. Terminal 4 is the connectionfor equipment ground. When the relay has input controlpower, Terminals 9 and 10 will have this potential onthem.Terminal Block Two (TB2): TB2 is located on the rightside of the rear panel and is numbered 1 through 15.Terminals 6, 7 and 8 are Form “C” contacts on the tripalarm relay and change state whenever a protective trip isinitiated by the relay. After a protective trip, the contactsremain in the changed state until the “Reset” Pushbutton ispressed. These contacts can be fed to the MP-3000 orMP-4000 discrete input to indicate a differential trip. TheMP-3000 or MP-4000 then can report the differential tripover either the INCOM or MODBUS network.Terminals 14 and 15 are a “NO” configurable contact. Thiscontact closes when the relay detects a need for the circuitbreaker to trip due to a differential current above the userprogrammed set point for a period of time in excess of theuser defined time delay setting. These contacts can be fedto the MP-3000 or MP-4000 discrete input to indicate adifferential trip. The MP-3000 or MP-4000 then can reportthe differential trip over either the INCOM or MODBUSnetwork.Rear Surface Terminals: The rear surface terminals,identified as (A1, A2), (B1, B2), and (C1, C2) provide thecurrent transformer input connection points and are ratedfor 5 ampere inputs. (A1, A2), (B1, B2) and (C1, C2) arephase A, B, C current inputs respectively.2-2.3 EXTERNAL HARDWAREThe MD-3000 Protective Relay requires that a customersupplied source of input control power be wired into theTB1 terminal block located on the rear panel. Refer to thetypical wiring diagram in Figure 3-1. A power supply canbe either ac or dc voltage within the acceptable voltageWARNING