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...
On Thu, 30 Oct 2014 15:01:34 -0700 (PDT), "
wrote:

On Thursday, October 30, 2014 1:36:31 PM UTC-4, Jim Wilkins wrote:

. What he
wants
to know is if he ran the welder from a Rotary Phase Converter
would
the current spikes and voltage drops be less. I don't know. I
also
don't know if there is a way besides my friend paying thousands
for
PSE to install a new xmfr on the pole for this situation to be
ameliorated. He can't afford at this time for a new welder with
a
softer start setting. Besides, the hard fast start means his
employee
can make more welds. Any help would be greatly appreciated.
Thanks,
Eric

You could look into turning it on with a Zero Crossing Relay.
http://www.crydom.com/en/Tech/Newsle...ng%20types.pdf
Can you check the voltage, current and power fector with a scope?

-jsw

Not a good idea. This is from Wiki.

Transformers

When a transformer is first energized, a transient current up to 10
to 15 times larger than the rated transformer current can flow for
several cycles. Toroidal transformers, using less copper for the
same power handling, can have up to 60 times inrush to running
current. Worst case inrush happens when the primary winding is
connected at an instant around the zero-crossing of the primary
voltage, (which for a pure inductance would be the current maximum
in the AC cycle) and if the polarity of the voltage half cycle has
the same polarity as the remnance in the iron core has. (The
magnetic remanence was left high from a preceding half cycle).
Unless the windings and core are sized to normally never exceed 50%
of saturation, (and in an efficient transformer they never are, such
a construction would be overly heavy and inefficient) then during
such a start up the core will be saturated. This can also be
expressed as the remnant magnetism in normal operation is nearly as
high as the
saturation magnetism at the "knee" of the hysteresis loop. Once the
core saturates however, the winding inductance appears greatly
reduced, and only the resistance of the primary side windings and
the impedance of the power line are limiting the current. As
saturation occurs for part half cycles only, harmonic rich waveforms
can be generated, and can cause problems to other equipment.
For large transformers with low winding resistance and high
inductance, these inrush currents can last for several seconds until
the transient has died away (decay time proportional to ~XL/R)and
the regular AC equilibrium is established. To avoid magnetic inrush,
only for transformers with an air gap in the core, the inductive
load needs to be synchronously connected near a supply voltage peak,
in contrast with the zero voltage switching which is desirable to
minimize sharp edged current transients with resistive loads such as
high power heaters. But for toroidal transformers only a
premagnetising procedure before switching on allows to start those
transformers without any inrush current peak.

I would contact the welder manufacturer and ask them if they know of
any good solutions. And maybe contact the power company and ask
them the same question.
He can't be the only one with that problem.

Dan
Jim,
I ehm not sure how to measure power fector with scope. Maybe Boris,
he know. Ahl esk him. Actually, how does one go about measuring
power
factor with a TEK 465B scope?
Thanks,
Eric

You need a current probe to see the phase difference between voltage
and current.
http://www.cappels.org/dproj/aciprob...rentProbe.html

-jsw