Many thanks we have discovered oil in the generator but it is also corroded on the com.

It is burning the diode out only, but we are going to carry out the tests.

Neil

Hello,

If the main relay is burnt out first you have to measure the isolation of the generator and the drive motor with 500V (you can have oil inside them and then you don't have the right output 230V and 148 A, the excitation has to be 24V and 17,1 A).
If there are no problems there, just post here for more support.

Best regards.