Eaton Cooper Power NR Series Maintenance Instructions Manual

Contents

6. Clean the internal components:A. Remove all traces of carbon by wiping with a cleanlint free cloth. Flush the mechanism with clean, drytransformer oil.B. If additional cleaning action is necessary, adielectric cleaner (Biogenic® Electrosafe fromRochester Midland, Positron Dielectric Cleaner, orsimilar) may be used to clean internal parts. Checkwith your local regulating authorities to determinewhich dielectric cleaners are permitted in your area.After the cleaner has evaporated, the mechanismmust be thoroughly flushed or dipped in clean, drytransformer oil to remove all cleaner residue. Evendielectric cleaners with high dielectric strengthleave a residue that will affect oil insulatingproperties if not removed.7. Check the moving and stationary contacts.A. Dress slight pitting and discoloration with crocus cloth.B. Replace both the moving and stationary contactsif they are severely eroded. Follow procedures in"Shop Repair Procedures—Contacts" section.ote:N The contacts should be replaced before the erosionof the load current transfer surfaces impairs theireffectiveness.8. Manually close and trip the switch several times tocheck that all components perform properly.9. Inspect tank lines. Note that two liners are employed.The inner liner is fibrous and readily absorbs anymoisture present. Soft or spongy areas indicate waterhas been absorbed. Replace the liner if such areas arepresent. The outer liner need not be replaced unless itis cracked or punctured.10. Check the dielectric strength of the insulating oil.A. A sample taken near the bottom of the tank shouldhave a dielectric strength of not less than 22 kV.B. Low dielectric strength indicates the presence ofwater or carbon deposits; replace the oil. (See "OilCondition" section.)11. If oil must be replaced, drain the tank and discard thetank wall liners.12. Thoroughly clean out all sludge and carbon depositsand rinse the tank with clean oil.13. Install new tank wall liners and fill the tank with clean,new insulating oil to within one inch of the top of thetank flange. Oil capacity is approximately 1.5 gallons.ote:N Use only new, or like-new reconditioned transformeroil which conforms to the specifications in ReferenceData R280-90-1, Oil Specifications and Test.14. Replace all external seals and gaskets.15. Clean the head gasket seat and retank the switch.A. Replace the head bolts and torque to 15 ft-lbs.Apply clamping force gradually and equally, in rota-tion, to each bolt to achieve an evenly distributedgasket sealing pressure.16. Electrically operate the switch to check for proper oper-ation. See "Operating Instructions—Electrical Operation"section.17. Repeat the high voltage dielectric withstand test (Step3) to make sure the dielectric clearances within thetank have not been compromised.Operating instructionsElectrical operationThe switch may be opened and closed electrically byapplying rated control voltage to the proper terminals of theactuator terminal block. Figure 3 illustrates a connectiondiagram for a standard three-wire control.NOTE: G=Ground2=Close3=OpenMOTOR0 1 G 2 3 4BlackRedAC-White, DC-BlackAC-Black, DC-RedSELSW.NOCNCFigure 3. Typical connection diagram for three-wirecontrol.Closing: Approx. 1.5 secOpening: Approx. 4 secCAUTIONDielectric failure, equipment damage. Never use volatilesolutions, detergents, or water-soluble cleaners whencleaning the interior of this equipment. These cleanerswill contaminate the insulating oil, reducing its dielectricstrength. Operation with contaminated insulatingoil can result in internal flashovers that will causeequipment damage and possible personal injury. T201.24TYPE NR OIL SWITCH MAINTENANCE INSTRUCTIONS MN230001EN February 2016