Fire and overhear detectors (firewires) out of resistance.
At my airline we had a 747 engine fire detector element (firewire) that waa out of resistance. The resistance was 10.2 M ohms and it should be no more than 80 ohms.
We Megger'ed the firewire from the core to the outside with 500 volts and it brought down the resistance to below 80 ohms.
Does anyone know why this process works? Some people call it whetting but I struggle to understand why it works.
Thanks