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RE: Three phase conversion In Rush current Concern.



Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>

No question, the rotary converter concept is bullet proof. The IGBT's in
the drive are rated at 1700V best case, and likely only 1200 or 1400 V.
More obvious is all of the micro processing that runs the thing. If you
were to have an accident with the drive, it could get expensive in a
hurry.

If you just want a bullet proof inrush limiting solution, try a series
reactor like we mentioned early on in this thread.

Yes, the more rotating mass the bigger your "filter" will be. This will
also make it harder to start however. (More inrush). True you could
start them in steps, however it will be more mechanically challenging to
integrate a starting clutch in place of your Lovejoy coupling.


Leigh


-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: October 2, 2006 7:32 PM
To: tesla@xxxxxxxxxx
Subject: RE: Three phase conversion In Rush current Concern.

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

Hi Leigh, et al,

I'm just going with my intuition here, but it seems to me as we bring
more
solid state electronics into a hammer and anvil scenario, something is
going
to break. On the other hand, solid state without question makes the best
phase relationships.

Do these apply to high power Tesla coils? I think not. Please disprove
me.

I am thinking I have a 5 hp three phase inductive motor with the same
RP/M
as my primary Idler motor 20hp/5hp. Since it is well proven that adding
motors to the rotating field increases the HP in a shop of many motors,
what
would be the net effect of coupling a dual union with let us say a "Love
Joy" mechanical joiner in phase. Would this not have the effect of an
additional flywheel like device?

Still just brain storming here... Tesla's teacher went on record as
saying
Tesla's rotating magnetic field concept was a "perpetual motion
machine". I
rate it as high efficiency.

Long Sparks, and Safe Haven,

Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Monday, October 02, 2006 8:36 AM
To: tesla@xxxxxxxxxx
Subject: RE: Three phase conversion In Rush current Concern.

Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>

True, a drive designed for 3 phase won't (good analogy on the mechanical
inertia as a filter by the way - a lot of people miss the dualism),
however one properly designed for single phase would be ideal.

A current source inverter (CSI) based drive (9-1/2 tenths of the drives
out there are VSI based) makes a great single phase to three phase
converter, because the DC link inductor is sufficiently large that the
120 Hz ripple is almost completely eliminated.

Leigh

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: September 30, 2006 8:10 PM
To: tesla@xxxxxxxxxx
Subject: RE: Three phase conversion In Rush current Concern.

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 11:26 AM 9/30/2006, Tesla list wrote:
  >Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>
  >
  >Hi Jim
  >
  >If and when you add the generator to your converter, the output will
  >be about as perfect as perfect can be, and this problem will be a
  >thing of the past.
  >
  >Regardless of how balanced your three phase ends up however, of
  >course we know that power in is going to be somehwat more than power
  >out, because even state of the art rotary converters (M-G sets) are
  >less than 85% efficient. (A good drive will beat this without any
  >moving parts BTW).


But a good solid state drive (while efficient) won't do as a good a
job turning single phase into 3 phase (in terms of ripple) because
the MG set essentially is using mechanical inertia as the low pass
filter/energy storage medium in the "DC link" (the DC just happens to
be unidirectional mechanical motion here).