奇怪的现象求个解释

rabbit3ear

The problem is linked to alternator as per description / specs below:Maker: Hyundai Electrical Engineering Co. LTDModel: HFC5 632-84E-OWS/N: 00-9RAL080-03Present running hours: 49204Driving end: Wartsila 8L20 Reported problem is very unusual and all our attempts to solve it with our own crew and / or external contractors so far didn’t bring us any success.  Reported problem as follows:440V Main Switch Board Insulation alarm comes up as soon as alternator is connected to MSBD and under any load. Insulation indicator arrow goes anticlockwise over infinity, if earth test button is pressed all three earth lamps are getting to flicker.Problems appeared first time after disintegrating of rubber coupling between engine and alternator.  Service has completed internal / external tests as per below description.1.       Bearing - engine side - was renewed from ship's stock due to increased temperature when in operation 2.       Rotor megger test (result: 100 000 M-ohm): with voltage 1000V. 3.       Stator megger test (result: 100 000 M-ohm): with voltage 1000V. 4.       Check all Cable Connections – OK 5.       Generator Voltage checked and found to be Constant 6.       AVR Replaced with New – Did Not have any affect 7.       Entire control Panel including theristors – Varistors – Resistor - Tandem Resistors and Capacitors from No 2 Alternator was installed – Did Not Have any affect 8.       Space Heaters Elements Checked – OK  MSB Side 1.       Main Air Switch Breaker checked found OK 2.       Current Transformers used to give readings on Panel and Power Management System, Checked – Initially indicated that this could cause the problem – but even when they were disconnected as soon as Alternator was loaded alarm re appeared. 3.       Earth Meter was Connected Directly to the Main Air Switch Breaker  indication was OK when engine was operating without Load – when load was introduced to the alternator earthing problem re appeared. 4.       Synchronization Unit Checked between Generators 1 & 3 and found OK 5.       Isolators on MSB checked / cleaned 6.       Current – Transducer – Frequency – Voltage signals checked on the pms controllers in the MSB 7.       Governor Controller checked in both Manual & Auto  found OK 8.       Earth Monitor Supply – Found OK 9.       Earth Monitor replaced with same unit from Emergency Switchboard with No affect. 10.   Checked the Voltage between each phase and earth with Following Readings a.       R : 247 Vb.      S : 258 Vc.       T : 268 V d.      When checking the voltage between phases we get Voltage of 447 V 11.   Checked the transformer 460/115 V for Measure and Earth Testing 12.   Checked the transformer 460/115 V for the OCR Source13.   Checked the transformer 460/115 V for Measure and Generator Protection 14.   Checked the transformer 460/115 V for ACB Control Unit. Basically all components have been shifted from one generator to another, it includes all respective controls. So far no any success achieved.For easy understanding I have dropped short video on following link: https://www.dropbox.com/s/woh9kbuzjnf2bc7/IMG_0259.MOV Your suggestions, advice, thoughts will be highly appreciated.