DC Rectifier

[Bob Larter]

Bruce Varley wrote:

"David Eather" <eather@tpg.com.au> wrote in message
news:CfCdnbn9C83grzLXnZ2dnUVZ_hGdnZ2d@supernews.com...
Bob Larter wrote:
moffie wrote:
TR wrote:
Work on a workboat. Installed as our 24 volt DC system for control and
lighting is a 240 VAC input / 24 VDC 120A output rectifier with battery
backup. The rectifier has failed. Was a home built job from nearly 20
years ago. The builder I believe (Lynden) has since passed on. Would
appreciate it if someone could recommend a company in Australia that
could supply something similar.
Many thanks.
TR.
Hi TR, I don't know where you could get a 120 amp rectifier, maybe an
old
stick welder?, but you can get 35amp rectifiers from jaycar or dick
smith. you
can join 5 of them together in parallel which would give you 175 amp,
Wouldn't work. The one with the lowest Vf would explode, then next
lowest, & so on.


"The one with the lowest Vf would explode, then next lowest, & so on"

Which should give you a clue on how to proceed down that path - add a very
low ohm resistor in series with each bridge (something in the order of the
hundredths of ohms range) so that the worst current hog only gets a
maximum of 35 amps.

Nuh, the resistors have to be in series with each individual diode.

Oops. I missed that the last poster specified only a single resistor.
You are of course correct about needing a resistor per diode.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[David Eather]

Bob Larter wrote:

Bruce Varley wrote:
"David Eather" <eather@tpg.com.au> wrote in message
news:CfCdnbn9C83grzLXnZ2dnUVZ_hGdnZ2d@supernews.com...
Bob Larter wrote:
moffie wrote:
TR wrote:
Work on a workboat. Installed as our 24 volt DC system for control
and lighting is a 240 VAC input / 24 VDC 120A output rectifier
with battery backup. The rectifier has failed. Was a home built
job from nearly 20 years ago. The builder I believe (Lynden) has
since passed on. Would appreciate it if someone could recommend a
company in Australia that could supply something similar.
Many thanks.
TR.
Hi TR, I don't know where you could get a 120 amp rectifier, maybe
an old
stick welder?, but you can get 35amp rectifiers from jaycar or dick
smith. you
can join 5 of them together in parallel which would give you 175 amp,
Wouldn't work. The one with the lowest Vf would explode, then next
lowest, & so on.


"The one with the lowest Vf would explode, then next lowest, & so on"

Which should give you a clue on how to proceed down that path - add a
very low ohm resistor in series with each bridge (something in the
order of the hundredths of ohms range) so that the worst current hog
only gets a maximum of 35 amps.

Nuh, the resistors have to be in series with each individual diode.

Oops. I missed that the last poster specified only a single resistor.
You are of course correct about needing a resistor per diode.

You do not need a resistor per diode, but you do need 2 resistors on the
inputs (or outputs) of each bridge.