Regular Member
Joined: 18/12/2020
Location: New ZealandPosts: 92
| Posted: 11:46am 21 Nov 2021 |
Thanks for the question. Short answer: No.
How? Easy: Wire a full bridge rectifier across each phase - schematically uses 12 diodes rather than the more common approach of 6 diodes to form a single DC from 3 phases.
3 bridges sub-divides the three phases into 3 DC supplies but I am not sure whether they are isolated, probably not, but I am not sure if the bridge rectifiers in effect achieve isolation. Maybe someone here can get their head around the question of isolation, and whether its necessary. I'd need to run it up and see if the three DC supplies had a voltage relationship to each other, I would have thought they would, but thinking about it as I type converting to DC what is the relationship to each DC supply? There may be a voltage difference of some relationship between the three DC outputs, which might then be important....
FWIW only 2 isolation transformers would probably be enough to isolate all 3 - if done that way.
Isolation could be done using transformers (on the AC side before rectification) with matching coils but probably more simply and cheaply simply separating the three phase coils should do it.
Look at the great information on this site about the F@P motor re-wiring, the coils are joined together at one end of the coil runs, that is not necessary, the three coil series could be run out giving three independent matching power circuits.
I recall the Honda Inverter 2.0 Generators which have 3 phase coils joined together in the usual star pattern for the mains feed, but also have a separate 12V coil for the 12 V output, presumably rectified from a single phase too.
Most people will have things with a single phase rectified into DC..... whether their houses are supplied with single or 2 or 3 phase supplies. Not convinced? If you are running off grid you are probably running a single phase inverter and feeding appliances that convert and use DC. Routers. Phone chargers come to mind as examples.