Thor Forums

[Chance]

Originally Posted by Oneilkeys

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I could be wrong, but i think that the way Thor has this wired, the emergency start switch plays no part in the BIRD/Trombetta operation. I think it is wired completely separately and physically connects the two battery banks with a wire running for one bank to the other thru the emergency start switch. When the switch is pushed, it physically connects the two banks and when the switch it let off, it separates them. The five wire BIRD has a wire that acts as that switch and closes the Trombetta, but in the Axis, I'm not sure the emergency start switch closes the Trombetta. I think it works separately from the Trombetta to connect the two battery banks. I am not sure of that, but from fooling around with the system, I think that is the way it works.

The diagram posted above clearly shows that the emergency start switch operates the Trombetta (brand name) isolator relay. The emergency start switch sends control current to close the Trombetta relay. There is no way that engine starting current, which would be in the 100s of Amps, could go through the emergency start switch itself which is limited to something like 5 Amps.

The reason these Trombettas are used is that they are available to handle very high current. Some models go up to at least 800 Amps, which should easily start a V10 engine.

When you depress the emergency start switch, a very low current (less than 5 Amps) will flow from the house batteries to the coil on the Trombetta (brand) relay, which in turn CLOSES the main contacts that allows 100s of Amps to flow from the house battery to the engine starter (assuming you are cranking the engine).