Eaton VR+ Series Instruction Book

Contents

26 Instruction Book IB182923EN September 2018 www.eaton.comAMH-4.76-VR+VR-Series+ Replacement Circuit Breaker6.5 INSULATIONIn VR-Series+ circuit breakers, insulation maintenance primarilyconsists of keeping all insulating surfaces clean. This can be doneby wiping off all insulating surfaces with a dry lint free cloth ordry paper towel. In case there is any tightly adhering dirt that willnot come off by wiping, it can be removed with a mild solvent ordistilled water. But be sure that the surfaces are dry before placingthe circuit breaker in service. If a solvent is required to cut dirt, useIsopropyl Alcohol or commercial equivalent. Secondary control wiringrequires inspection for tightness of all connections and damage toinsulation.6.6 INSULATION INTEGRITY CHECKPRIMARY CIRCUIT:The integrity of primary insulation may be checked by the ac highpotential test. The test voltage depends upon the maximum ratedvoltage of the circuit breaker. For the circuit breakers rated 4.76 kVthe test voltage is 15 kV RMS 60Hz, 27kV RMS 60 Hz for circuitbreakers rated 8.25 kV and 15 kV. Conduct the test as follows:Close the circuit breaker. Connect the high potential lead of thetest machine to one of the poles of the circuit breaker. Connectthe remaining poles and circuit breaker frame to ground. Startthe machine with output potential at zero and increase to thetest voltage. Maintain the test voltage for one minute. Repeat forthe remaining poles. Successful withstand indicates satisfactoryinsulation strength of the primary circuit.Open the circuit breaker. Connect the high potential lead of thetest machine to one of the terminals of the circuit breaker. Connectthe remaining terminals and circuit breaker frame to ground. Startthe machine with output potential at zero and increase to thetest voltage. Maintain the test voltage for one minute. Repeat forthe remaining poles. Successful withstand indicates satisfactoryinsulation strength of the primary circuit.SECONDARY CIRCUIT:Isolate the motor by disconnecting the two motor leads from theterminal block. Connect all points of the secondary disconnectcontact pins with a shooting wire. Connect this wire to the highpotential lead of the test machine. Ground the circuit breakerframe. Starting with zero, increase the voltage to 1125 RMS, 60 Hz.Maintain the voltage for one minute. Successful withstand indicatessatisfactory insulation strength of the secondary control circuit.Remove the shooting wire and reconnect the motor leads.6.7 PRIMARY CIRCUIT RESISTANCE CHECKThe main contacts of the VR-Series+ circuit breaker are insidethe vacuum chamber where they remain clean and require nomaintenance at any time.The dc electrical resistance of the primary circuit may be calculatedby measuring the voltage drop across the circuit. This test shouldbe performed with a low voltage, direct current (dc) power supplycapable of delivering no less 100A dc.• To check the primary circuit resistance:• Remove the circuit breaker from the circuit breakercompartment• Close the circuit breaker• Pass at least 100A dc from terminal to terminal of each poleunit in the closed position• Measure the voltage drop across the terminals.The resistance can be calculated from Ohm’s Law and is expressedin micro-ohms. Repeat for the remaining two poles.The resistance should not exceed the factory test levels more than200% as stated in IEEE C37.09. Factory test levels are recordedon the circuit breaker test form, which is included with the circuitbreaker. If measurements exceed 200%, contact the manufacturer.Resistance conversion for TemperatureRconversion = RFactory(1 + (TField - TFactory)r)Rconversion = Resistance correction for temperature based from thefactory resistance measurement.RFactory = Resistance measurement from the factory.TField = Temperature measurement in the field.TFactory = Temperature measurement from the factory.r = Copper resistivity temperature coefficient.r = 0.0039 Copper Resistivity Temperature Coefficient / Deg Cr = 0.002167 Copper Resistivity Temperature Coefficient / Deg F6.8 VR-SERIES+ CIRCUIT BREAKER ELEMENT MECHANISMCHECKMake a careful visual inspection of the mechanism for any looseparts such as bolts, nuts, pins, rings, etc. Check for excessive wearor damage to the circuit breaker components. Operate the circuitbreaker several times manually and electrically. Check the closingand opening times to verify that they are in accordance with thelimits in Table 4.6.8.1 CLOSURE™ TESTIntroductione: The CloSure™ Test is a simple yet extremely effectivemeans to determine and monitor the ability of the mechanism toclose the circuit breaker contacts fully. It provides a quantitativemeasure of the extra energy available in terms of over travel ininches to close the circuit breaker contacts to their full extent. It maybe used periodically to monitor the health of the mechanism.Gtntral Informatione: The CloSure™ Test can be performed on allVR-Series+ circuit breakers. (Refer to Table 6.2.) If the CloSure™travel obtained is as specified, the mechanism performance issatisfactory. If the CloSure™ travel does not conform as shownin Figure 6.14, contact Eaton’s Electrical Engineering Services &Systems for further information. (See Step 14).m DANGERDO NOT ATTEMPT TO INSTALL OR PERFORM MAINTENANCE OR TESTS ONTHE EQUIPMENT WHILE IT IS ENERGIZED. NEVER PUT YOUR HANDS NEARTHE MECHANISM WHEN THE CIRCUIT BREAKER IS IN THE CHARGED ORCLOSED POSITION. DEATH OR SEVERE PERSONAL INJURY CAN RESULTFROM CONTACT WITH ENERGIZED EQUIPMENT. ALWAYS VERIFY THATNO VOLTAGE IS PRESENT BEFORE PROCEEDING WITH THE TASK, ANDALWAYS FOLLOW GENERALLY ACCEPTED SAFETY PROCEDURES.Saftty Prtcautionse: Read and understand these instructions beforeattempting any maintenance, repair or testing on the circuit breaker.The user is cautioned to observe all recommendations, warnings andcautions relating to the safety of personnel and equipment.otte:N Htaring prottction is rtcommtndtd as tht circuit brtaktr isoptntd and clostd.The recommendations and information contained herein are basedon Eaton experience and judgment, but should not be considered tobe all-inclusive or covering every application or circumstance whichmay arise. If further information is required, you should consultEaton’s Electrical Services & Systems.Ttsting Proctdurtse: Assuming that the circuit breaker is safelyremoved from the circuit breaker compartment enclosure andpositioned in an area outside the arc fault boundary, follow thisprocedure to perform the CloSure™ test. For further instructions onremoval of the circuit breaker from the circuit breaker compartment,refer to the appropriate section of this manual.