PRO-POINT MIG-ARC-TIG 145A Manuel De L'utilisateur page 17

V1.0 145A MULTI-PROCESS MIG-ARC-TIG WELDER 8619470
(Fig. 22-2). Pressure is applied by a tension arm, which can be adjusted to increase or decrease the
pressure as required. The type of wire will determine how much pressure may be applied and what
type of drive roller is best suited to obtain optimum wire feed.
V-Shaped Groove - Solid hard wire, like steel or stainless steel, require a drive roller with a V-shape
groove for optimum grip and drive capability. Solid wires can have more tension applied to the wire
from the top pressure roller that holds the wire in the groove and the V shape groove is more
suited for this. Solid wires are more forgiving to feed due to their higher cross sectional column
strength. They are stiffer and do not easily bend.
U Shaped Groove - Soft wire, like Aluminum, requires a U-shape groove. Aluminum wire has
less column strength, can bend easily and is therefore more difficult to feed. Soft wires can
easily buckle at the wire feeder where the wire enters the torch's inlet guide tube. The
U-shaped roller offers more surface area grip and traction to help feed the softer wire. Softer
wire also requires less tension from the top pressure roller to avoid deforming the wire's shape.
Too much tension will push the wire out of shape and cause it to catch in the contact tip.
Knurled Drive Roller - Flux core/gasless wire is made of a thin metal sheath that has fluxing and
metal compounds layered onto it, which is then rolled into a cylinder to form the finished wire. The
wire cannot take too much pressure from the top roller, as it can be crushed and deformed. A
knurled drive roller was developed with small serrations in the groove. The serrations grip the wire
and assist to drive it without too much pressure from the top roller. The down side of using a
knurled wire feed roller with flux cored wire is it will slowly eat away at the surface of the welding
wire over time. These small bits eventually dislodge and go down into the liner. This will clog the
liner and the added friction will lead to welding wire feed problems.
A U-groove wire can also be used for flux core wire without the wire particles coming of the
wire surface. However, it is considered that the knurled roller will give a more positive feed of
flux core wire without any deformation of the wire shape.
OPERATION
FEATURES
THERMAL OVERLOAD PROTECTION
Constantly exceeding the duty cycle can damage the welding unit. An internal thermal protector
will open when the duty cycle is exceeded, shutting OFF all functions except the cooling fan. Leave
the welding unit turned ON with the fan running. The thermal protector will automatically reset and
the welding unit will function normally again once it has cooled.
Wait at least another 10 minutes after the thermal protector opens before resuming welding.
Starting before this additional time may result in a shortened duty cycle.
OVER-VOLTAGE
This equipment has an automatic voltage compensation function, which enables the unit to
maintain the voltage within the given range. In case that the input voltage or amperage exceeds
the stipulated value, it is possible to damage the equipment's components. Please ensure your
primary power supply is correct (See Specifications).
DOWNSLOPE SETTING
Downslope is the gradual reduction of power to the electrical arc at the end of the welding
process. The power reduction allows the metal to cool more slowly and avoid a brittle weld or
stress cracks.
Downslope begins after releasing the torch trigger to shut off the welding arc. Power reduces
over a preselected time of 1 to 10 seconds (E). At the end of the selected duration, both the arc
and gas are stopped. The crater fill operation is automatic to factory-preset level.
IMPORTANT! This feature is only recommended for welding jobs that exceed 70 amps.
Visit www.princessauto.com for more information 17