Air Liquide Saf-Fro PRESTO 300MV Instructions D'utilisation page 8

EN
5 - CONNECTION AND PREPARATION FOR WELDING
SWITCH OFF THE WELDING MACHINE BEFORE
CARRYING OUT THE CONNECTIONS.
5.1 - MANUAL SHIELDED METAL ARC WELDING (MMA).
Connect the welding accessories carefully in order to avoid power losses.
Carefully comply with safety rules.
1. First determine the proper polarity for the electrode to be used (consult
the electrode data for this information).
2. Fit the required electrode on the electrode holder.
3. Connect the welding cables to the output terminals of the unit for the
selected polarity:
4. ATTENTION: insert the male connector with the key lining up with
the keyway and rotate approximately ¼ turn clockwise. Do not
over tighten.
a. For stick DCEP (Direct Current Electrode Positive) connect the
electrode holder cable to positive weld output terminal (Ref.4-Fig.2).
b. For stick DCEP (Direct Current Electrode Positive) connect the work
lead to negative weld output terminal (Ref.5–Fig.2) and the clamp
near the welding zone.
5. Shown here below is the connection method for DCEP welding.
6. The connection of these two connectors as made above will result in
welding with "reverse polarity" (shallow penetration).
7. For stick DCEN (Direct Current Electrode Negative) switch the cables
connections at the machine to obtain welding with "straight polarity"
(deep penetration).
8. Turn ON the machine (Ref.A-Fig.3) and select the Electrode welding
mode (Ref.19–Fig.8).
9. Select the Hot Start and Arc Force functions thru the selection key
(Ref.13-Fig.8):
a. With the Hot Start LED ON turn the regulation knob (Ref.3-Fig.8) to
adjust the Hot Start value; the display will view the set value (from 0
to 75 max.). The duration of the Hot Start function is fixed to 1.4 sec
(it's not possible to change).
b. With the Arc Force LED ON turn the regulation knob (Ref.3-Fig.8) to
adjust the Arc Force value; the display will view the set value (from 0
to 99max.).
c. After 5 seconds, the unit will automatically exits from the regulation
menu or press a second time the select key (Ref.13-Fig.8) to exit
immediately. The LED (Ref.15-Fig.8) turns ON again.
10. Adjust the arc length (Ref.12–Fig.8): if the arc length is too long it will
cause spatters and small fusion of the welding piece. If the arc length
is too short the arc heat will be insufficient causing the electrode to
stick to the work piece; the right balance of the arc length in relation to
the welding application and type of electrode must be found.
CONNECTION AND PREPARATION FOR WELDING
Fig.4
11. VRD (Voltage Reduction Device): as default the device is OFF in MMA,
to activate it, press once for 5 sec. the key (Ref.12-Fig.8). With the
VRD function ON at the end of welding the unit is OFF (stand-by), to
automatically restart when the electrode gets in touch with the work piece.
12. Pre-set the welding current on a range from min. to max. available (its
value depends on the supply voltage available in the area and by the
welding process) using the Encoder Control knob (Ref.3-Fig.8)
13. To use remote control: connect the remote control connector to the
10 pins receptacle on the front panel (Ref.6 – Fig.2) and enable it with
the key (Ref.13-Fig.8). In this condition the current can be adjusted
independently of the setting made on the unit, but attention: the max
welding current by remote control depends on the value set on the
front panel with the Encoder Control Knob (Ref.3-Fig.8).
14. The welding current should be chosen following the instruction given
by the electrodes manufacturer on the electrode box, but the following
indications may be useful as general information:
Thicknesses for flat
welding,
butt welding and
fillet welding (mm)
1.6
2.0
2.0-3.0
3.0-5.0
6.0-10
> 8.0
NOTE: ADJUST THE WELDING CURRENT ACCORDING TO
THE DIAMETER OF THE ELECTRODE TO BE USED AND THE
PROCEDURE IN COURSE.
5.1.1 - FEATURES ENABLED WITH MMA WELDING
HOT START.
This is a temporary increase in the initial welding current. This helps ignite
the arc quickly and reliably.
ANTI-STICKING.
This is a function that decreases the output current of the machine to a
low level when the operator makes an error and sticks the electrode on
the work piece. This decrease in current allows the operator to remove
the electrode holder without creating large sparks that can damage the
electrode holder.
ARC FORCE.
This is a temporary increase in the output current during normal welding.
This temporary increase in output current is used to clear intermittent
connections between the electrode and the weld puddle that occur during
normal stick welding.
ARC LENGTH.
This is an active control feature that guarantee the best arrangements
between the arc stability and spatter presence. The control measure in
each instant the output voltage and it determines the power to break with
the mapped Arc Force level the metal drop that is transferred from the
electrode to the work piece as guarantee the arc stability. With this feature
the welding operations are simplified and the welded joins looks better.
EN-8
Electrode Average
diameter intensity for
(mm) rutile electrodes
(A)
1.6 40
2.0 55
2.5 70
3.2 110
4.0 160
5.0 200
Tab.1