HV ELECTRICAL SYSTEM 51 8. ISOLATION MEASUREMENT A. BEFORE DOING TEST FOLLOW SAFETY CHECKS Turn off Vehicle Ignition. Remove LV/Aux. Battery ve terminal. Remove HV Battery Manual Service Disconnect(MSD) Fuse. Check if all earth connections of components are connected to vehicle body/Chassis. B. AFTER ISOLATION RESISTANCE TEST Reconnect all HV connectors. Reconnect HV battery Manual Service Disconnect (MSD) Fuse. Reconnect LV/Aux battery ve terminal C. ISOLATION TESTER(ISOLATION TESTER) D. COMMON TEST PROCEDURE: 1. Connect test probes(+ve & -ve Probes) to the Isolation tester. 2. Turn ON Isolation tester and select appropriate voltage range i.e(500 V). 3. Connect +veterminal of Isolation tester Probes to Conductor. 4. Connect -veterminal of Isolation tester probe to vehicle chassis/component body. 5. Press and Hold Isolation tester’s test button. 6. Check isolation Resistance value on Isolation tester display & also check If voltage builds to 520 to 550 V. 7. If voltage doesn’t build to 500 V and Isolation resistance is less than 0.25 M Ohm there could be some issue in vehicle HV isolation. 8. To find out where is the issue refer isolation failure conditions. E. ISOLATION RESISTANCE VALUES Minimum Isolation Resistance when connected in System : >0.25 M ohm with >500 V Minimum Isolation Resistance of Individual Cable or Component : >10 M Ohm with >500 V F. ISOLATION RESISTANCE FAILURE CONDITIONS: 1. Isolation Failure Issue during Cranking / Running a. Isolation Resistance checking for E Compressor: Procedure – E Compressor & PTC Heater 1. Remove 3IN1 combo side E compressor HV connector. 2. Connect +ve terminal of Isolation tester to +ve terminal of removed connector & -ve terminal of Isolation tester to 3IN1. 3. Check Isolation resistance on Isolation tester display.IR value should be more than 0.25 M Ohm and voltage should build 520 to 550 V. 4. Connect +ve terminal of Isolation tester to -ve terminal of removed connector & -ve terminal of Isolation tester to 3IN1body. 5. Check Isolation resistance on Isolation tester display.IR value should be more than 0.25 M Ohm and voltage should build 520 to 550 V. 6. If the isolation resistance value is acceptable limit then reconnect the connector. If Value is less than acceptable limit. 7. Remove E Compressor side connector.
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