Jo men skulle inte högre diodbryggan redan dubbla utspänningen genom kondensatorena, jmfd vänster 12V diodbryggan?
Vad gäller dioderna i generatorer så har de väll oftast DO-208 eller DO-21 hölje och det verkar vara som att de oftast tål 200-600V. Om de tål 600V borde man inte behöva vara så orolig att de inte ska klara 10x högre spänning än 14 eller 28V.
Hittade förresten ett intressant dokument om (24v) laddningsystem i engelska militärfordon med och utan dubbla batterier för radio sändmottagare här
https://lrch.nl/sites/default/files/allchargedup_0.pdf Vissa hade även en 210V (208V) AC 400Hz trefasutgång för elverktyg genom en 115/208V trefas-transformator som är ansluten till alternatorns växelström:
Citat:
Data for Alternator, No.1, Mk 1
Rotax Code number BA 2803
FVRDE number FV342586
Note rpm quoted is alternator speed not engine speed.
DC Output (from rectifier unit) 28.5 volts at 100 amps over range 1,800-12,000 rpm
AC Output (3-phase) 208 volts 400 Hz. 12 kVA at 8,000 rpm
Det visar att denna 28,5V 100 A alternator (2,85 kVA) klarar av att att producera 115V 11.7 kVA vid högre varvtal och alltså har en minst lika hög utström (100A)!
Citat:
Power Tools, Transformer, No.2, Mk 1
The power tools transformer provides two three-phase outputs for power tools in addition a further supply for battery charging. It is used in installations with one or two alternators.
Power tools require three-phase 208 volts at 400 Hz, this is provided by the power tools transformer stepping up the 115 volt output from the alternator. In order to provide this output the alternator must be run at 8,000 rpm, not only so that the power tools revolve at the correct speed but also as transformers are designed for a given frequency any deviations from this will cause inefficiency and heat generation. The main output transformer consists of three auto-connected windings in a star configuration and will deliver 11.7 kVA.
There is a second output winding arranged as a delta. This provides two outputs:
1. Three-phase 8.3 kVA, 208 volts at 400 Hz.
2. Three-phase 25 volts to the rectifier unit, when rectified this translates to 28.5 volts DC at 100 amps.
There is a third output consisting of two small toroidal windings in an open star configuration. The output of this is rectified by six diodes and is adjusted by a variable resistor to provide a 28.5 volt DC reference voltage. The reference voltage is needed for the control panel when the output voltage is 208 volts AC three-phase.
There are three configurations of output depending how plugs are connected:
1. 200 amp 28.5 volts DC. Normal usage with both alternators. Transformer not connected.
2. 12 kVA 208 AC and 100 amps 28.5 volts DC. Using both alternators. Transformer connected.
3. 8 kVA 208 AC and 100 amps 28.5 volts DC. Using only one alternator. Transformer connected.