Pulse Mig Operation - Everlast PowerMTS 251Si Operator's Manual

Section 3
The Power i-MIG 275P pulse designis a single-
pulse wave form that features full manual con-
trol of the pulse parameters. This means that
the pulse action of the unit varies between two
user defined levels of voltage while welding.
To understand the Everlast Pulse MIG design
and setup, it is important to recognize and dis-
cuss basic types of Pulse MIG welders to help
you understand how the Power i-MIG 275P is
similar and different in design, setup and oper-
ation.
The Types of Pulse MIG Welders. There are
many different types of pulse MIG welders.
Every brand has their own type or types of
pulse MIG welders. Over the years, pulse MIG
welders have changed in design and function
and multiple types of Pulse MIG may be repre-
sented under one brand. Many times it is diffi-
cult to pinpoint the differences in the pulse
function from generation to generation or
model to model as many companies prefer to
explain the effects rather than the functions.
There are nomenclature differences as well
from brand to brand and model to model. One
function may be called by one name by one
company, while the same function is called by
another name by another company. Some
offer more fine tuning control over the param-
eters than others. Over the years pulse MIG
welders have definitely evolved. This has cre-
ated a lot of confusion and misunderstanding
in the industry by users about what pulse MIG
welding is and what it is capable of. Training
seminars provided to dealers of one type of
brand may indeed teach a Pulse MIG product
feature is unique or special by trademarking a
name of a control while another brand has the
same exact feature but is called by another
name. It has lead to a lot of confusion in the
industry. However, to be clear, there are two

PULSE MIG OPERATION

Basic Theory and Function
major categories of pulse MIG welders: single
(or simple) pulse, and double (or pulse-on-
pulse) pulse. With most single-pulse MIGs,
the current is pulsed between two preset cur-
rent values, creating a simple, square type of
DC wave form. With a double-pulse type of
MIG, the unit actually pulses between 4 pulse
current levels, with at least two low pulse val-
ues and two high current values. In the most
simple terms, this creates a stepped wave
form which looks and sounds different than a
single pulse, simple up and down wave form.
The main advantage of the double pulse MIG,
when it is properly set-up, is a clearly defined
ripple similar to what you'd find in a corre-
sponding TIG weld. The way these current val-
ues are pulsed can also vary.
The Basic Theory and Purpose Behind Pulse
MIG. Regardless of the type of pulse MIG we
are referring to, most pulse MIG welders are
cycling several times a second between high
and low values of current (amps). Many single
pulse MIG welders cycle between 20-500 Hz.
This allows good control over the heat being
put into the weld. The basic reason for using a
single-pulse MIG is to prevent overheating of
the weld metal while maintaining a rapid dep-
osition rate without compromising fusion. Sin-
gle-pulse MIG welding is mostly done in pulsed
-spray mode. Pulsed-spray is a modification of
the Axial spray mode, where the metal actual-
ly pinches off before the wire touches the
weld puddle, without shorting the arc. Axial
spray is accomplished by using higher volts
and amps than would be used in a short circuit
transfer process. Historically, the most com-
mon applications for Pulse MIG welding are in
aluminum or stainless. Currently, though, sin-
gle-pulse MIG welders are being used braze
with Silicon bronze in auto body repair shops.
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