I think a product already exists.  When one wants to control the speed
of a 3 phase induction motor, one either uses a very cumbersome antique
method that I won't bother to explain, or uses a frequency drive.  A
frequency drive, or freq drive for short, takes two or three phase AC,
converts it to DC, then through a very powerful and computer controlled
inverter, converts it back to AC, and can range the frequency from around 40
to 400 hz.  By directly driving the DC into the freq drive, you can program
the frequency, then go away.  There are also bells and whistles that can be
employed if you would like.  These drives can control motors and also
provide you clean three phase power.  There are many safety features built
in as well.
    Of course, if you want to build one of your own, then that is even more
fun!



SO.....Whaddya REALLY  want??

Carl R, McIver  (usually)
or the wife (Janet) and kids

Pull your head out to send me e-mail!
jncmcivryourhead@gte.net

-----Original Message-----
From: marcel <marbel@XS4ALL.NL>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Monday, May 18, 1998 1:50 AM
Subject: 3fase ac power generator


>I am interested to do an project to generate 3 phase ac mains on a ship
>on board there are
>two dc generators dc 220 volts and battery's
>an old tow boat from russia
>siemens makes power bridge's igbt  10 to 50 amps 600 volts
>i saw a design with 80553 pwm to control this bridge
>did any body do research on this which pic could do the job
>the bridge contains rectifier and 6 igbt transistors so one needs 6 pwm
>out puts
>
>
>
>
>Marcel
>
>marbel@xs4all.nl
>
>Amsterdam