Special Maintenance - Telwin Modular 20 TI Manuel D'instructions

6.2 ADJUSTING THE PARAMETERS
6.2.1 6.9kA Models
- Select the thickness of the sheet to be spot-welded using the key (2 - FIG. C) on
the spot-welder control panel.
- Select the type of spot-welding (continuous or pulsed) using the key (3 - FIG. C).
When necessary it is possible to correct the default spot-welding time upwards or
downwards using key (1- FIG: C).
6.2.2 Model 5.8kA
Regulate the spot-welding time using the potentiometer (9 - FIG.B1) on the back of the
spot-welder; using the lowest possible values compatible with correct execution of the
spot-weld (see 6.3 PROCEDURE).
6.3 PROCEDURE
To make a spot-weld, power the spot-welder then follow the instructions below:
- place the bottom electrode on the sheet to be spot-welded;
- pull the clamp lever to the end of its stroke, and hence until the microswitch is
pressed (8 - FIG.B) so that:
a) the sheets close between the electrodes with the preset force;
b) the welding current passes for the preset time.
- release the clamp lever shortly afterwards. This delay (holding) improves the
mechanical properties of the spot-weld.
When specific experience is lacking we recommend carrying out a number of test
welds using sheet of the same thickness and quality as that of the workpiece.
The spot-welding operation is deemed correct when a tensile test causes the spot-
welding core to come out of one of the two sheets.
WARNING! The spot welder is equipped with a protective conductor
that connects the welding circuit directly to earth.
Weld only if the plates to be joined are insulated against earth!
If they are not, immediately interrupt welding and get a technician who is expert
or qualified on this subject to check the system and spot welder protective
conductor.
7. MAINTENANCE
WARNING! BEFORE CARRYING OUT MAINTENANCE, MAKE SURE
THE SPOT WELDER IS OFF AND DISCONNECTED FROM THE MAINS AND THE
PNEUMATIC SUPPLY SOURCE (if present).
With versions operated with pneumatic cylinder, the main switch must be locked
at "O" using the supplied lock.
7.1 ROUTINE MAINTENANCE
ROUTINE MAINTENANCE CAN BE CARRIED OUT BY THE OPERATOR.
- electrode tip diameter and profile adaptation/restoration;
- electrode alignment check;
- spring load check (electrode strength);
- spot welder and clamp power cable integrity check
- electrode and arm replacement;
7.2 SPECIAL MAINTENANCE
SPECIAL MAINTENANCE MUST ONLY BE CARRIED OUT BY TECHNICIANS
WHO ARE EXPERT OR QUALIFIED IN AN ELECTRIC-MECHANICAL FIELD.
WARNING! BEFORE REMOVING THE SPOT WELDER PANELS
AND LOOKING INSIDE IT, MAKE SURE THE SPOT WELDER IS OFF AND
DISCONNECTED FROM THE ELECTRIC AND PNEUMATIC (if present) POWER
SUPPLIES.
If checks are carried out while the inside of the spot welder is live this could
cause serious electric shock due to direct contact with live parts and/or injury
due to direct contact with moving parts.
Periodically and as frequently as required by the use and environmental conditions,
inspect inside the spot welder and remove the dust and metal particles that have
deposited on the transformer, thyristor module, diode module, power terminal board,
etc. using a blast of dry compressed air (max. 5 bar).
Do not direct the jet of compressed air onto the electronic circuit board; if
necessary clean them with a very soft brush or suitable solvents.
At the same time:
- make sure the wiring does not show signs of insulation damage or loose - oxidised
connections.
- lubricate the joints and the pins.
- make sure the screws that connect the transformer secondary with the cast arm-
holders are tight and that there are no signs of oxidation or overheating; do the
same for the arm locking and electrode-holder screws.
- make sure the screws that connect the transformer secondary with the output bars
/ wires are tight and that there are no signs of oxidation or overheating.
- check machine earthing circuit continuity with the welding circuit (electrodes).
- make sure the transformer secondary screws (if present) are tight and that there
are no signs of oxidation or overheating.
- after having carried out maintenance or repairs, restore the connections and wiring
as they were before, making sure they do not come into contact with moving parts
or parts that can reach high temperatures. Tie all the wires as they were before,
being careful to keep the primary high voltage connections separate from the
secondary low voltage ones.
Use all the original washers and screws when re-closing the structural work.
7.3 TROUBLESHOOTING
SHOULD MACHINE OPERATION NOT BE SATISFACTORY, AND BEFORE
CARRYING OUT MORE SYSTEMATIC CHECKS OR CONTACTING YOUR
TECHNICAL ASSISTANCE CENTRE, MAKE SURE THAT:
- When the welding lever is activated the microswitch is effectively pressed, giving
the control board permission to weld.
- The heat protections have not cut in.
- The elements that are part of the secondary circuit (cast arm-holders – arms –
electrode holders – cables) are not inefficient because of loose screws or oxidation.
- The welding parameters (electrode strength and diameter, welding time) are
suitable for the work being carried out.
- 7 -