Everlast Typhoon 500 Operator's Manual page 54

Component Identification and Explanation
Explanation of TIG Parameters, Functions and Welding Terms
decrease of the amperage and provides a window to fill the crater as the
puddle begins to cool before the arc terminates. Used with all remote
functions except the foot pedal.
End Amps. This is the destination current value set for the end of the weld
cycle. When used with the torch switch, this is the final current set used
to taper off and fill the crater at the end of the weld. For foot pedal use,
this value should be kept at a minimum for proper tail off. However, the
Tungsten size will ultimately dictate the exact minimum Amperage that a
stable tail off of Amperage can be performed.
Gas Purge. This function is useful for setting and testing the gas flow rate.
It activates the solenoid and opens it up so that gas can flow freely without
having to fire the torch. It should always be used instead of firing the
torch to activate the solenoid. The LED will stay lit until it is deactivated. It
can also be used as a diagnostic to test gas solenoid valve operation.
High Frequency Start (HF). Depicted as HF on the menu screen under the
start function, this is a touchless type of start. It is actually an simulated
HF electronic controlled start, but due to the familiarity of users with HF, it
is labeled as such to avoid confusion. When HF start is selected, the user
positions the torch 1/8" or less above the weld area and either presses the
foot pedal or the torch switch and the arc will jump. This HF start is creat-
ed by a HV electronic system, instead of the traditional point gap design. A
high voltage, low amperage current is created which jumps from the Tung-
sten to the work piece when activated. Once the machine sends a High
Voltage impulse to the torch, the HV energy jumps the gap between the
electrode and the work piece. Then, the welding arc will initiate after conti-
nuity is established. When continuity is established, the HF/HV shuts off.
On this unit the HF/HV parameters can be programmed in the back ground
menu. The length of HV start attempt, the strength of the HV arc and the
HV impulse Amperage can all be set in the background menu. Once set,
these parameters will seldom be changed. If the arc attempts to start long-
er than the set time, an error code "E05" will be displayed temporarily,
meaning the switch is either stuck closed, or the arc has been activated too
long without an arc start. This helps prevent damage to the machine and
chance of accidental shock to the user. Do not "air fire" with the pedal or
torch switch unless testing functions. Use the gas purge to set gas flow
rate instead of firing the torch. The arc should only be used to strike an arc
against the work piece.
The HF on an inverter is not continuous. Formerly the term "HF" was
synonymous with AC welding as it was required continuously to help
stabilize the arc on a transformer welder since switching time in AC was
so slow. The two terms were often confused used interchangeably.
Inverter switching frequencies are so rapid that the need for continuous
HF overlay is eliminated. HF now refers to the HV arc start.
Lift Start. Lift start requires touchdown and lifting up of the Tungsten to
start the Arc. It is usually used only with DC output since some contamina-
tion of the tungsten is possible. But it can also be used with AC where HF
NOTICE:
energy is prohibited, such as in a hospital environment. There are two
types of Lift Start that this unit has. The first is a live lift start. This means
the tungsten is always electrically live until the arc is started. When the
tungsten is touched to the metal, continuity is sensed and the welder
sends welding power as soon as the continuity is broken. If you need this
type of start on a welder, contact Everlast for other product information.
The other type of lift start is a "remote lift start". It functions essentially the
same except, the tungsten is not electrically live and the torch switch or
foot pedal must be used to make the torch live. This is a safer form of lift
start and helps prevent accidental starting of the arc. It also means that
the start type can be used with the welder programming in 2T and 4T
mode, or with the foot pedal.
Post Flow. Post Flow is the amount of time (in seconds) that the shielding
gas flows after the arc is terminated. This is an important function. The
flow of shielding gas after welding is stopped helps to 1) Cool the torch
and tungsten and prevents oxidation of the tungsten as it cools. 2) Provide
cooling and shielding while the weld puddle solidifies and cools. This
helps to prevent the weld from forming porosity and prevents oxidation of
the weld as it cools. Post Flow should be increased at the Amperage in-
creases. For simple calculation, add one second of Post Flow for every 15
to 25 Amps used. At a minimum, 2 to 3 seconds should always be used.
To properly use Post Flow, the torch should be held in place over the weld
after termination until the gas shuts off.
Pre Flow. Pre Flow is the amount of time (in seconds) that the shielding
gas flows before the weld starts. It is very important that the Pre Flow be
set for at least a short flow before any weld. The Pre-Flow not only purges
the torch of any contamination, but it also establishes a protective enve-
lope of shielding gas around the weld before the arc initializes. This pro-
tects the tungsten, and helps to establish an arc more quickly by sur-
rounding the tungsten and work with more easily ionized gas so that arc
starts are more efficient. It also allows time for the gas flow to stabilize
before the arc is struck. When initializing the Pre Flow a "rush" of gas can
often be heard just ahead of the arc strike. Then the gas flow will quieten
down as the weld begins. This is normal. This rush of gas is caused by
several things, but it is in part due to regulator attempting to regulate the
sudden rush of gas. As it does this, extra gas may be consumed until the
regulator has had time to react. The extra flow of gas may create turbu-
lence around the weld. The Gas flow rate may also temporarily increase
due to the back pressure "ballooning" of the gas lines. As the slightly
swollen gas lines stabilize, extra gas is propelled as the solenoid opens
relieving the back pressure. Using .3 to .7 seconds is usually enough to
allow the "gas rush" to stabilize, unless extra large shielding cups are
used. If over-sized cups are used (≥#10), increase to 1 to 2 seconds.
The arc start will be delayed by the amount of time chosen for Pre Flow.
If Pre Flow is set for 2 seconds, the arc will not start for 2 seconds. This
is sometimes easy to forget, especially when tacking or "Bump" welding.
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NOTICE: