[Boatanchors] Fw: High-current connection with multiple wires?

[manualman at juno.com]

What happens if one of the secondary windings short? That's a lot of
short circuit current flowing. 

Pete, wa2cwa

--------- Forwarded message ----------
From: Charles via Boatanchors <boatanchors at mailman.qth.net>
To: BoatAnchors Digest <boatanchors at mailman.qth.net>
Date: Mon, 7 Mar 2022 18:51:01 -0600
Subject: [Boatanchors] High-current connection with multiple wires?
Message-ID: <a621b41e-eecd-c639-fe75-118cf56cc09d at centurytel.net>

I acquired a 5 KVA toroid transformer with eight individual 20 VAC, 31 
amp secondaries that I plan to use for a really hefty unregulated 24 
volt supply (the 250 amp RMS total translates to about 140-150 amps DC 
in a simple bridge/capacitor circuit). The leads are all 10 gauge 
stranded. Looking for suggestions as to the best way to join them all 
into two short heavy leads that will connect to my heat-sinked 200 amp 
bridge rectifier (1/4" bolts).

There are a variety of bus bars on the market, either screw 
compression-type or studs (which require crimp lugs).

It might be possible to put all eight #10 into one big crimp lug, but I 
don't know how to calculate the size that would be required. Maybe 2/0? 
I do have a big enough ratcheting crimper for that.

A quick and dirty way could be to use a piece of #8 solid copper (only 
0.6 milliohms per foot) and solder all the #10 stranded to it, close 
together. Then I only have to figure out how to join the #8 solid to a 
short piece of #4 stranded, routed to the bridge rectifier.

Or flatten a piece of 1/2" copper tubing, solder the wires to it (or 
drill holes, use crimp lugs and bolts), drill a hole in the end for the 
#4 conductor's lug i.e. make my own bus bar.

There seems to be quite a few different ways to do this - it's more of a 
mechanical than an electrical problem ;)

Any thoughts?
thanks
-Charles, WB3JOK/0 since '76 :)