Telwin PTE 18 Manuel D'instructions page 12

4.3 INTERLOCK AND SAFETY FUNCTIONS
4.3.1 PTE Models
Thermal safeguard.
Triggers if the spot-welder overheats due to insufficient flow or lack of cooling water or
to an excessively heavy duty cycle.
Triggering is indicated by the yellow LED
EFFECT:curre nt shutdown (welding disabled).
RESET: automatic when temperature returns within allowed limits (yellow LED goes
off).
4.3.2 PCP Models
General switch
- Position " O " = open, can be padlocked (see chapter 1).
WARNING! In position "O" = internal power supply cable terminals (L1 + L2) are
live.
- Position "I" = closed: the spot welder is in ST AND BY
Emergency function: while the spot-welder is running (opening the switch from "I" =>
to "O" position), the spot-welder will shut down, in safety mode.
- current off;
- electrodes opening up (cylinder discharging);
- automatic re-start disabled.
Start-up push-button
You must push this button in order to control the welding operations (from the
pneumatic pedal) in each one of the following conditions:
- whenever the general switch has shut off (position "O" => position "I");
- whenever the safety/protection devices have triggered;
- whenever the (electric and compressed air) power supply returns after being cut
off due to a fault or disconnection.
Cycle selector
/
- Cycle : it allows the control of the spot-welder (from the pneumatic pedal)
without welding. It is used to move the arms and to close the electrodes without
power supply.
FURTHER RISKS! Be aware that even in this machine mode the risk of crushing
the upper limbs exists. (see chapter on safety).
- Cycle (normal welding cycle) enables the spot-welder to make the weld.
Thermal safeguard
Triggers if the spot-welder overheats due to insufficient cooling water flow rate or to an
excessively heavy duty cycle.
This intervention is signalled by the yellow LED
EFFECT : current off (welding disabled).
RESET : manual (push the button
allowed limits (yellow LED switches off).
Compressed air safety switch
Triggers if there is a compressed air pressure drop or failure (p<2.5 ÷ 3 bar). This
intervention is signalled by the gauge (0 ÷ 3 bar) located on the compressed air input
system.
EFFECT : movements blocked: electrodes opening up: cylinder released.
Current off: welding disabled.
RESET : manual (push button
(On the gauge: >>3 bar).
5. INSTALLATION
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WARNING! CARRY OUT ALL INSTALLATION OPERATIONS AND
ELECTRICAL AND PNEUMATIC CONNECTIONS WITH THE SPOT -WELDER
COMPLETELY SWITCHED OFF AND DISCONNECTED FROM THE POWER
SUPPLY OUTLET . THE ELECTRICAL AND PNEUMA TIC CONNECTIONS MUST
BE MADE ONLY AND EXCLUSIVEL Y BY AUTHORISED, SKILLED PERSONNEL.
________________________________________________________________________________________________________________
5.1 PRELIMINARY OPERATIONS
Unpack the spot-welder, assemble the separate parts as indicated below.
5.2 LIFTING THE SPOT -WELDER (FIG. E)
The spot-welder should be lifted with a double cable and hooks, using the eyebolts
fitted for this purpose.
It is absolutely prohibited to sling the spot-welder in a different way from the one we
prescribed (e.g. on arms or electrodes).
5.3 POSITION
The installation area must be sufficiently large and without obstacles, suitable for
ensuring safe access to the control panel and to the work area (electrodes).
Ensure that there are no obstacles near the cooling air inlets and outlets and that no
conductive dusts, corrosive vapour, humidity, etc. can be sucked in.
Position the spot-welder on a plane surface made of homogeneous and compact
material (floor made of concrete or similar physical characteristics).
Fasten the spot-welder to the floor by means of four M10 bolts, using the special holes
on the base; each individual element anchoring the spot-welder to the floor must
guarantee a tensile strength of at least 60 Kg. (60daN).
Maximum load
The maximum load that can be applied to the lower arm (concentrated on the
electrode axis) is 35 Kg. (35daN).
lighting up on the control panel.
mode
(green LED on
l
ocated on the control panel.
) after the temperature returns within the
) after the pressure reaches the allowed limit.
5.4 CONNECTION TO THE MAIN POWER SUPPLY
5.4.1 Warnings
Before making any electrical connection, make sure the rating data of the spot-
welder correspond to the mains voltage and frequency available at the place of
installation.
The spot-welder should only and exclusively be connected to a power supply system
with the neutral conductor connected to earth.
5.4.2 Connecting the power supply cable to the spot-welder (FIG.F)
Remove the right side panel, assemble the supplied cable clip at the hole drilled on the
back panel.
Pass the power supply cable through the cable clip and connect it to the power supply
block (phases L1(N) L2) and to the screw terminal of the yellow-green earth protection
conductor.
Depending on the terminal block model, fit the cable terminals as shown in the diagram
(FIG.F1, F2).
Block the cable by tightening the screws on the cable guide.
).
See the "TECHNICAL DATA" paragraph for the minimum allowed section of the
conductors.
5.4.3 Plug and socket
Connect the power supply cable to a standardised plug (3P + G, only two pins are
used: INTERPHASE CONNECTION!) of adequate capacity and prepare a power
outlet protected by fuses or by an automatic circuit-breaker; the appropriate earth
terminal should be connected to the earth conductor (yellow-green) of the power line.
The capacity and specifications of the fuses and circuit-breaker are given in the
paragraph on "TECHNICAL DA TA".
Should several spot welders be installed, distribute the power cyclically among the
three phases in order to obtain a more balanced load; e.g.:
spot-welder 1: power supply L1-L2;
spot-welder 2: power supply L2-L3;
spot-welder 3: power supply L3-L1.
_____________________________________________________________________________________________________________________
WARNING! Failure to observe the rules given above will invalidate the (class
I) safety system provided by the manufacturer causing serious risks to people
(e.g. electric shock) and objects (e.g. fire).
_____________________________________________________________________________________________________________________
5.5 PNEUMATIC CONNECTION (FIG. G )
(PCP models only)
- Set up a compressed air line with working pressure of at least 6 bar.
- Screw the pressure GAUGE (supplied with the spot-welder) into the special threaded
hole located on the pressure reducing valve.
- Connect a flexible pipe for compressed air (internal diameter 8-9) through the special
opening located on the rear of the machine to the lubricator-reducer-filter group
connector located on the left side; seal off with suitable hose clamps. Pour ISO FD22
oil into the lubricator cup through the special cap (screw).
5.6 CONNECTING THE COOLING CIRCUIT (FIG.H)
It is necessary to set up a water delivery pipe for maximum temperature 30 °C, with
minimum flow rate not less than that specified in TECHNICAL DA TA. It is possible to set
up an open cooling circuit (discarding the return water) or a closed circuit as long as the
temperature and water flow rate parameters are respected.
Remove the left side panel in order to reach the flexible delivery and return water pipes
and then pass them through the special openings located on the rear panel. Connect
the delivery pipe (marked by a label) to the external water supply, ensuring correct
discharge and flow rate in the return pipe.
WARNING! Welding operations performed without or with insufficient water flow could
cause the spot-welder to break down due to overheating.
6. SPOT WELDING
6.1 PRELIMINARY OPERATIONS
Before carrying out any spot-welding operation it is necessary to make a series of
checks and adjustments, which should be carried out with the general switch in the "O"
position (with the padlock closed in PCP versions) and with the compressed air supply
switched off (DISCONNECTED).
- Ensure that the electric connection is done according to the previous instructions.
- Put the cooling water into circulation.
- Adjust diameter "d" of the electrode contact surface according to the thickness "s" of
the sheet to be spot welded, according to relationship
- Between the electrodes slide a shim equivalent to the thickness of the sheet to be
spot welded; ensure that the arms, brought together manually, are parallel and that
the electrode holders are centred.
If necessary, make some adjustments by loosening the electrode holder locking
screws until you find the most suitable position for the job to be performed; secure
the locking screws tightly.
In models PTE and PCP28, the gap between the arms can also be regulated by
adjusting the fastening screws of the lower armholder casting (see technical data).
- Open the safety gate located on the rear of the spot-welder by loosening the four
fastening screws to get at the electrode force adjustment nut (wrench No.30).
Compressing the spring (screw the nut clockwise) will cause the electrodes to exert
gradually increasing force with values between the minimum and the maximum (see
technical data).
Such force will increase in proportion to the increase in the thickness of the sheets to
be welded and to the diameter of the electrode tip.
- Close the gate to prevent extraneous matter from entering and to prevent accidental
contact with live or moving parts.
- Check the compressed air connection in PCP models, connect the feed pipe to the
pneumatic system, adjust the pressure by turning the reducer knob until the gauge
reads 6 bar (90 PSI).
6.2 ADJUSTING THE PARAMETERS
The parameters determining the diameter (section) and the mechanical resistance of
spot welding are:
- force exerted by the electrodes (daN); 1 daN = 1.02 Kg.
- diameter of the electrode contact surface (mm);
- welding current (kA);
- welding time (cycles): at 50Hz 1 cycle = 0.02 sec.
- 12 -
d = 4 ÷ 6 · √s.