Use Of The Equipment - TECNA 7900 Manual Del Usuario

COOLING CIRCUIT INSTALLATION (ONLY ITEMS 7903-
7903P)
For a correct cooling of the welder it is necessary 150 l/h clean
water at a maximum temperature of 30°C. When connecting the
unit to the water line check for dirt or packing scraps in the
hoses and connect the supply to the inlet G, and the drain to the
outlet H, this to allow that still cool water immediately reaches
the parts of the welder most subject to heating.
Water-cooling may be carried out by the following methods: with
mains water supply, with re-circulating water, with heat
exchanger (air-water) or with refrigerator. When working in high
humidity with mains water supply or refrigerator, avoid the use
of water at a low temperature in order to prevent moisture being
produced inside the machine. In presence of hard water it is
necessary to install a water softener in the inlet hose, this to
avoid that deposits obstruct or reduce the water channels in the
welder causing damages. If the machine is operated in a re-
circulating water supply, the water softener must be placed on
the supply of the tank for cooling water.

USE OF THE EQUIPMENT

Before connecting the unit to the power supply, check if the
welder voltage corresponds to your mains voltage, as well as
that both the power socket and system are in a good condition,
and that the mains cable section is of the correct size (see table
5).
Check that the required performance is within the values stated
on table 3 and 4.
Before starting work, carry out the following adjustments:
1 - Set up the arms and electrodes.
2 - Adjust the electrodes force.
3 - Set the welding parameters.
The following paragraphs better describe the above stated
adjustments.
Before starting working, check that all safety warnings have
read and understood.
The push-button (53) activating the timer and supplying the
welding current is activated by closing the electrode by means
of control lever (25).
Release the electrodes 0,2"-0,8" after the welding current has
stopped; this delay improves the weld quality.
Electrodes must not be used to force the clamping of the pieces
to weld.
Always monitor the electrodes which must always be clean,
without any deformation . The truncated electrodes must have
the proper diameter according to the work to be carried out.
"РУТЕКТОР" - сертифицированный дистрибьютор TECNA S.p.A. на территории РФ. rutector.ru info@rutector.ru 8 800 100 00 69
A Electrodes
B Electrode-locking
C Arms
E Electrode force scale
P Timer-pulses selector (for versions P only)
9 Movable arm holder
17 Electrode force index
18 Electrode force adjustment
25 Electrode force lever
33 Mains cable
47 Welding current adjustment (only items 7902-7903)
53 Welding start push-button
56 Welding time adjustment
77 Fixed arm holder
Before starting the welding process, check the welding
parameters (time, pressure, etc.). Use two off-cuts of the sheet
to be welded; the spot is correct when the pulling test causes
the coming out of the welding nugget with the hole of a sheet.
The twist test shows a pure area without porosity (see fig. 5).
When the work is over, disconnect the welder from the mains
supply.
Never carry the welder by its cord or yank it to take it off from
the socket. Keep the cord away from heat, oil and sharp edges.
Items 7903-7903P only.
The cooling water must circulate for some minutes after the
welding cycle has been accomplished, so to enable the
welder cooling. Never let the cooling circuit open if the
machine is not used, so to avoid both leakage and the
forming of moisture.
ADJUSTMENTS
Arms and electrodes set up.
With electrodes A clamping the pieces, the arms C should be
parallel and the electrode tips must combine (fig. 1). To adjust
them slacken the locking pin B, shift the electrode A, and block
again. If it is necessary, pull out the arms for 6 mm. maximum
(fig.2).
To disassemble and adjust the electrodes slacken locking pin B
screw on arms with electrodes
means of a slight hammer stroke for electrodes
75XX). On water cooled arms, to disassemble electrodes use a
key.

12 (range 74XX); hit the pin by

10 (range