Eaton VR+ Series Supplemental Instructions

Also see for VR+ Series: Instruction book Instruction book

Current Path Resistance TestPurposeTo measure and record the dc electrical resistance ofthe main current carrying pole unit assembly in theVR-Series+ power circuit breaker. This measurement isperformed by injecting 100A dc from terminal to terminalof each pole unit in the closed position and measuringthe voltage drop across the terminals. The resistancecan be calculated from Ohm’s Law and is expressed inmicro-ohms.The main contacts are inside the vacuum chamber,which remain clean and require no maintenance atany time. The VR-Series+ design does not have slidingcontacts at the moving stem and use a highly reliableand unique flexible clamp design that eliminates theneed for lubrication and inspection for wear.This test may be performed during regular maintenanceintervals and the results should not exceed the factoryrecorded values by 15% when adjusted to the sametemperature recorded during the factory tests.EquipmentThis test should be performed with a low voltage,direct current (dc) power supply capable of deliveringno less 100A dc. The factory performs this test using aDigital Low Resistance Ohmmeter (DLRO). The DLROinjects 100A dc, measures the voltage drop across theterminals and displays the resistance in micro-ohms.ProcedureThe current path resistance test is to be performed perANSI/IEEE C37.09-1999 section 5.5.TestPerform the test as follows (Using the DLRO)1. Remove the circuit breaker from its enclosure ifinstalled (follow the removal procedures) and move itto a suitable area away from the Arc-Flash boundary.2. Remove the finger clusters from the terminals beingtested.3. Manually or electrically charge the circuit breaker.4. Manually or electrically close the circuit breaker. Ifthe circuit breaker is being closed electrically, thecharging motor will run if control power is presentafter the circuit breaker is closed.5. Provide control power to the DLRO and turn it to theON position. Select 100A output, if adjustable.6. Connect the DLRO positive current lead to the TOPterminal of the phase being tested.7. Connect the DLRO negative current lead to theBOTTOM terminal of the phase being tested.8. Press the TEST button on the DLRO. Once theTEST button is pressed, 100A dc will flow throughthe phase being tested. If the circuit breaker is notclosed, the DLRO will not inject current.9. Apply the DLRO positive measurement test leadto the TOP terminal. Be mindful not to connect thismeasurement lead to the current lead. This insuresthat the current lead is not being calculated into theresistance of the current path.10. Apply the DLRO negative measurement test lead tothe BOTTOM terminal. Be mindful not to connect thismeasurement lead to the current lead. This insuresthat the current lead is not being calculated into theresistance of the current path.11. While both measurement leads are connected,observe the resistance reading and record the value.12. Press the TEST button on the DLRO to stop thecurrent flow.13. Remove the measurement leads and current leadsfrom the phase being tested.14. Install the finger clusters back onto the terminals ofthe circuit breaker.15. Repeat above procedure for the remain phases of thecircuit breaker.16. Open the circuit breaker after completion of thetesting.17. Turn the DLRO to the OFF position and removecontrol power if necessary.18. Re-insert the circuit breaker into the enclosure perinsertion procedures.ResultsThe field measured resistance should not exceed thefactory values no more than 15%. If measurementsexceed 15%, check the primary current path for loosehardware and re-torque per the VR-Series+ instructionbooklet. Repeat the test if any loose hardware andre-torqueing is applied. If the values do not improve,contact the manufacturer.Resistance conversion for TemperatureR conversion = R Factory ( 1 + ( T Field - T Factory ) r )R conversion = Resistance correction for temperature based from the factoryresistance measurement.R Factory = Resistance measurement from the factory.T Field = Temperature measurement in the field.T Factory = Temperature measurement from the factory.r = Copper resistivity temperature coefficient.r = 0.002167 Copper Resistivity Temperature Coefficient / Deg Fr = 0.0039 Copper Resistivity Temperature Coefficient / Deg CResistance Converter (In Degrees Fahrenheit):Rconversion Field =o FR Factory : T Factory : T Field :6EATON | Visual Instruction Booklet Essentials | November 2018