RDD16?
...
The stator insulation isn't designed to take on too much voltage and that alternator is rather weak anyway (35/25A).
It looks like RDD16 on other photo before it got his second life
I have 2A fuse on rotor coil which is powered by high frequency PWM from external battery 12V.
What could be safe maximum current for this rotor which creates magnetic field inside? As I remember its resistance was about 4 Ohm, so when powered from 12V battery 3Amax could flow without any additional resistor or I missed something?
Regulator makes no difference, it only controls maximum voltage allowed on the battery feed, not the actual charge current, which depends on battery float voltage ( difference on SOC from flat to the expected cut off at 14.4 volts on the regulator) and input shaft RPM only.
There is no oryginal voltage regulator no more while hacked and disabled built in
Also removed this useless one diode from rectifier, so no I have rotor coil wires, 3 phase windings and 3 phase rectifier with external regulator
Update: There is also this oryginal capacitor 2.2uF from rectified B+ to B-.
I've made custom alternator controller with analog Hall sensor SS495A based current sensing circuit and microcontroler (ATTiny85) with output voltage measurement and by adjusting PWM I can drive rotor coil regardless of its RPM and the limit is its maximum current.
It is diffcult to see gauge of this rotor coil, so decided put there 2A fuse for the moment.
Of course this alternator is not used in car no more
I can limit its output current and output power, so I can keep desired RPM regarless how low resistance is connected to its output, but it would be nice to have its datascheet like this another one
A93/90A - 13.5V 90A:
http://www.magnetimarelli.com/sites/default/files/SF_A93_90A_rev9.0_p.pdfwhere at typical performance graph we can see how much power we can get from it based on its RPM speed eg. 30A @ 3000 RPM.
I do not need more than 500 W (0.5kW) rush power but it would be nice to push to the limits its rotor current and maybe even add another custom cooler to be able to feed it with higher current
When bigger current is aplied more power is needed to turn rotor or keep his RPM, there is stronger magnetic field inside, so I should get higher current at voltage maybe too low for direct battery charging, but good for step-up boost switching regulator ICs and boost switching controller ICs