Eaton 380 VCP-Wind Instructions For The Use, Operation And Maintenance

Contents

I.B. 70A2580H02 Page 29Effective November 20126-5 INSULATIONType VCP-Wind 38kV Vacuum Circuit Breakersprimarily utilize epoxy insulation. Insulation maintenanceprimarily consists of keeping all insulating surfacesclean. This can be done by wiping off all insulatingsurfaces with a dry lint free cloth or dry paper towel. Incase there is any tightly adhering dirt that will not comeoff by wiping, it can be removed with a mild solvent ordistilled water. Be sure that the surfaces are dry beforeplacing the circuit breaker in service. If a solvent isrequired to cut dirt, use cleaning alcohol or commercialequivalent. Secondary control wiring requires inspectionfor tightness of all connections and damage toinsulation.6-6 INSULATION INTEGRITY CHECKPrimary Circuit:The integrity of primary insulation may be checked by the60Hz AC high potential test. The test voltage dependsupon the maximum rated voltage of the circuit breaker.For circuit breakers rated 38kV the test voltage is 60kVrms. Conduct the test as follows:Close the circuit breaker. Connect the high potentiallead of the test machine to one of the poles of thecircuit breaker. Connect the remaining poles andcircuit breaker frame to ground. Start the machinewith output potential at zero and increase to the testvoltage. Maintain the test voltage for one minute.Repeat for the remaining poles. Successful withstandindicates satisfactory insulation strength of theprimary circuit.If a DC high potential machine is used, make certainthat the peak voltage does not exceed the peak of thecorresponding AC rms test voltage.Secondary Circuit:Connect all points of the secondary terminal blockwith shooting wire. Connect this wire to the highpotential lead of the test machine. Ground the circuitbreaker frame. Starting with zero, increase thevoltage to 1125 volts rms. Maintain the voltage forone minute. Successful withstand indicatessatisfactory insulation strength of the secondarycontrol circuit. Remove the shooting wire.6-7 PRIMARY CIRCUIT RESISTANCE CHECKSince the main contacts are inside the vacuumchamber, they remain clean and require nomaintenance at any time. Unlike many typical circuitbreaker designs, VCP-Wind circuit breakers do nothave sliding contacts at the moving stem. Instead theyuse a highly reliable and unique flexible clamp designthat eliminates the need for lubrication and inspectionfor wear.Figure 6-2 Resistance Measurement Locations & Values TableVCPW-Wind