[Boatanchors] High-current connection with multiple wires?

[Charles]

Thanks - but what happens when the DC is slightly different due to those winding differences... the highest branch would hog current and its winding would get hot, along with its diodes! Also it'd be a wiring nightmare with eight bridges and eight filter caps...

Anyhow, I hooked them all up in parallel and let the transformer idle for a while and it didn't even get warm on our high (248) line voltage. I also put my Amprobe clamp-on ammeter on the primary side and it doesn't even move the needle on the lowest (0-6 amp) range. So I think we don't have to worry about balance issues :)
(I was also careful to keep the total lead length of each secondary the same, too).

I'm putting circuit breakers in not only the primary side, but also the DC output side :) If anything shorts, I'd expect the breaker to open, although the fireworks could be considerable until it does (and there's a lot of energy stored in that filter cap).

-Charles, WB3JOK/0

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If one winding or any of the parts used for  rectifying the AC to DC
shorts, the current from all the other rectified windings will feed the
short. Given the amount of current from all the other windings, you will
most likely destroy the winding in the short and possibly explode the
transformer.
The gauge of wire used in this environment needs to address possible
short circuit conditions by one or more of the individual AC to DC
circuits.

Putting that many DC outputs in parallel without considering possible
short circuit conditions and protection is a recipe for disaster.

Pete, wa2cwa
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Good suggestion. Otherwise slight differences between the windings are likely to cause high current draw and excess heat. Jim k0jjf


>/On 03/08/2022 5:38 AM Mike McCarthy, W1NR <lists at w1nr.net 
<https://mailman.qth.net/mailman/listinfo/boatanchors>> wrote: />//>/> />/My suggestion would be to have each winding rectified and filtered />/individually and combine the resultant DC to a copper bar bus. Then tap />/the bar with the appropriate wire size for the equipment in use. />//>/Mike, W1NR />//