Re: blown rectifier bridge question

These rectifier brigdes can be a bit missleading. The terminal
markings refer to DIAGONAL connection but only appear on one side of
the device leading you to think that one side is input and the other
output.

The terminal nearest the ~ mark (AC symbol) and the diagonally
oppisite terminal are AC input connections. The other two are the DC
output terminals where the capacitor connects in parallel. You don't
need the capacitor connected before anything else either. Make sure
you use the diagonal pairs of terminals.

You may not have blown the bridge after all. Theses are full wave
rectifiers with 4 diodes connected in a diamond pattern

DC
->|-0-|<-
AC~ 0-| |-0 AC~
-|<-0->|-
DC

If you get that poor ascii art! The ->|- and -|<- are diodes 0- is
a terminal. It seems the makers have stopped labelling the pakages
completly.



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "docholliday02743"
<whollid1@c...> wrote:

> Help! I am assembling my control box and have installed and wired

the

> fans and the toroid primary. I gently secured the rectifier bridge
> (from mouser, 25 amp 600v) I wired the 55vac to the a/c side of the
> rectifier and was going to read the d/c voltage at the d/c terminals
> before hooking anything up (capacitor, etc..) instand loud hum and
> shorted rectifier bridge! measured resistance across a/c terminals

of

> rectifier after this and it is shorted (0.2 ohms). Figured bad

bridge,

> installed 2nd bridge (this time testing resistance prior to hooking
> up, and instant short again. It isn't the secondary of the trans as
> that tests fine and there is no short if I plug in the primary from
> the trans and leave the secondary not connected to anything- good

a/c

> output and no short. I am wondering if the capacitor MUST be

installed

> before hooking up power?
>
> Help!
>
> Bill H