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dave r

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Joined: 19/04/2006
Location: Australia
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Posted: 07:51am 23 May 2006

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Good day
Just a question from someone not really up with electronics. I have just purchased 3 15 amp recfifiers from Dick Smiths. I noticed that the circuit on this site uses 3* units where as the circuit on yourgreendream site uses 2. Can someone just explain the difference
Thanks in advance
Dave R

dave rankin

Gizmo

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Joined: 05/06/2004
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Posted: 08:59am 23 May 2006

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Hi Dave

Each Bridge Rectifier has 4 diodes in it, but we only need 2 for each phase ( wire ) from our alternator. So on a 3 phase machine ( 3 wires ), we need 6 diodes, or 1 and a half bridges. So thats explains why some sites only use 2 bridge rectifiers, using all 4 diodes in one and 2 diodes in the other.

But what I prefer to do is use all 4 diodes in each bridge rectifer for each phase. If a bridge rectifier is rated at 15 amps, then by doubling up on the diodes I've doubled the amps it can handle, up to 30 amps. So by using 3 bridges, I've doubled the power it can handle compared to using only 2 bridges.

So I get twice the capacity for only 33% more cost.

But either way is fine.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

dave r

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Joined: 19/04/2006
Location: Australia
Posts: 11

Posted: 11:54pm 23 May 2006

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Thanks for the reply Glenn
That makes it easy to understand.
Regards
Dave

dave rankin

wallablack

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Joined: 10/08/2011
Location: Australia
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Posted: 10:54pm 28 Apr 2012

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This is, I am assuming, the wiring diagram in question.

LINKY

Does using 2 instead of 3 bridge recs have any performance downfalls?

Foolproof systems do not take into account the ingenuity of fools.

Gizmo

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Posted: 11:20pm 28 Apr 2012

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Since the circuit with 3 bridge rectifiers ( as shown here ) uses 2 diodes in parallel, there may be a tiny gain in power as there is less loss through the rectifier, but I guess the gain would be almost unmeasurable. So no, I dont exepect there is any noticable performance gain in using 3 bridges instead of 2.

There is a reliability gain with 3 bridges, since each diode is passing less current.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

wallablack

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Joined: 10/08/2011
Location: Australia
Posts: 164

Posted: 11:57pm 01 May 2012

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Okay, so, current question.

If I had 2 x 50 Amp 1000V KBPC5010,s wired -ive to -ive / +ive to +ive what would the voltage and amperage rating be?

If I had 3 x 50 Amp 1000V KBPC5010,s wired -ive to -ive to -ive / +ive to +ive to +ive what would the voltage and amperage rating be?

Edited by wallablack 2012-05-03

Foolproof systems do not take into account the ingenuity of fools.

Gizmo

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Posted: 02:10am 02 May 2012

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A. 1000V 50amps
B. 1000V 100 Amps

Basically your doubling its current carrying capacity, for and extra 50% in cost. Thats why I prefer the 3 bridge recitfiers.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

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