RE: Three phase conversion In Rush current Concern.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>


Jim:

I have not been following this thread so pardon me if my comments are
redundant.

I believe that your "3 phase converter" is the type where you are using
an idling motor(shown on your sketch) to allow one to drive a 3-phase
motor.  It is my understanding that this type of circuit will
temporarily run a 3-phase motor up to a point somewhat below its 3-phase
rating.  It is also my understanding that the circuit
loads(currents)will be seriously out of balance.  As a result, it is not
uncommon to eventually burn up the motor(not the idling one) when this
circuit is used.  Thus, I am not sure if it will drive your system the
way you want since it is not really 3 phase power that you are
developing.

I had originally thought you were building something like a generator
set where you were mechanically coupling a 1 phase motor to a 3-phase
generator(motor), driving the 1 phase with 220VAC/1PH and thus actually
generating 3-phase power from the 2nd motor/generator.  Obviously, this
is not the case, but this method would produce true 3-phase power.

You might consult www.3phasepower.org.  I believe they have extensive
information on 1 phase to 3 phase conversion.

Mark




>Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

>Hello All,

>Here is the schematic of my proposed three phase converter to power my
>>Raytheon 3 phase 24 KV DC power supply (I also have a generator in
>progress). The capacitors are mid-range based on other phase converters
>documentation and are subject to trail and error, to achieve balanced
>output.

>http://hot-streamer.com/temp/JimMora/3PhaseStaticIdlerMotor.pdf

>If anyone has experience in this arena I could use some help.

>The motor will run at ~3425 rpm which has the benefit of handling
>sudden change in current draw (think spark gap) and the disadvantage of
>inrush current to start it up.

>The motor will draw around 49 amp in static state load conditions. The
>>LR rating @ 240v is 290 amps, yikes. I have seen a few schematics of
>>"soft start" with triac's or SCR's.

>I think  my neighbors to the right will see a burnout as will their
>computers as we are a distance from the pig and the service wire is
>1950's # 4 I think. I have upgraded to 100 amp service. Beef connected
>to turkey at the Mast head.

>Any suggestions would be appreciated, I am a novice in poly phase, yet
>>know the complexities of a seeming simple circuit.

>Thanks Much,
>Jim Mora