I have a 12V, 90A alternator. I wanted to know how can I calculate its internal resistance. The specifications sheet I received from the manufacturer is a simple image, as shown below:
This alternator is going to be installed on a tractor for farm work. Its internal resistance is important as my add on modules (a GPS tracking and motor control device) protection devices are affected by it. My circuit has a SLD33 TVS diode by LittelFuse that can withstand load dump pulses from alternators that have Ri (internal resistance) >= 1 ohm.
Since this alternator is capable of delivering such high currents (upto 90A), I suspect it might have an internal resistance Ri much less than 1ohm. I will need to update my electronics circuitry with two SLD33 instead of one in that case.
With the help of above image, can anyone tell me how can I find the internal resistance of this alternator? Or if you are aware of any other method, then can you please share the details of the same?