Look at the International Rectifier web page.
They have the info and the components to do
what you want.

-Craig

----- Original Message -----
From: "Eric Smith" <eric@BROUHAHA.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, April 20, 2001 4:55 PM
Subject: [EE] three-phase power measurement, and rectifier output


> I posed the following two questions on sci.electronics, but got no
replies.
> I'm posting them here because I know that there are people here who have
> used PICs for power measurement.
>
>
>
> 1:
>
> I've been trying to figure out how to measure the power consumption on
> a three-phase wye circuit, and I'm stumped.
>
> Things I can measure:
>
> Vx, Vy, Vz:   voltage on each phase relative to neutral
> Ix, Iy, Iz:   current on each phase
> In:           current on neutral
>
> Wanted:  equation giving power consumption as a function of these
variables
>
> For instance, with a normal single-phase device I measure the power
> consumed by integrating Vx*Ix.  This is simpler because there's only a
> single path for the current.  In the three-phase case, there may be
varying
> phase-to-phase loads as well as phase-to-neutral loads.
>
> My first thought was to integrate Vx*Ix + Vy*Iy + Vz*Iz.  But this doesn't
> take into account any neutral current, and I'm not convinced that it would
> be right even for a three-phase delta circuit (no neutral).
>
>
>
> 2:
>
> I'm trying to figure out how to build a three-phase front end to a bunch
> of DC-DC converters (such as Vicor VI-200 series), and could use a bit of
> help.
>
> If I run three-phase delta power into a bridge rectifier as shown below,
> what is the relation between the phase-to-phase input voltage and the
output
> minimum, maximum, and average voltages?  Unlike a single-phase bridge
> rectifier, I know the minimum does not approach zero.
>
> The cases I am most interested in is 208V phase-to-phase (common in the
> USA).
>
> I've checked some of my electronics reference books, and they don't seem
> to cover this case.  Web searches for three-phase rectifiers on Google and
> Altavista come up with all sorts of information on "controlled
rectifiers",
> which replace three or six of the diodes with SCRs, apparently for voltage
> or power factor control.  But I can't seem to find anything covering the
> simple "uncontrolled" case.
>
>
>
> Any help with either question will be much appreciated!
>
> Thanks,
> Eric
>
>
>
> Crude ASCII art schematic of three-phase rectifier:
>
>
>
> phase X       |\ |
> -------+------| >|-------------+------------- V+
>        |      |/ |             |
>        |                       |
>        |                       |
>        |      | /|             |
>        -------|< |-------      |
>               | \|      |      |
>                         |      |
>                         |      |
>                         |      |
> phase Y       |\ |      |      |
> -------+------| >|------u------+
>        |      |/ |      |      |
>        |                |      |
>        |                |      |
>        |      | /|      |      |
>        -------|< |------+      |
>               | \|      |      |
>                         |      |
>                         |      |
>                         |      |
> phase Z       |\ |      |      |
> -------+------| >|------u------+
>        |      |/ |      |
>        |                |
>        |                |
>        |      | /|      |
>        -------|< |------+-------------------- V-
>               | \|
>
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