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FHF 5-1 HIGH-FREQUENCY IGNITION DEVICE
In the ignition process, a capacitor bank is charged by a DC power
supply and then abruptly discharged via the primary winding of the
air-gap reactor and of the spark gap. The high-voltage impulses
occurring here on the secondary winding of the air-gap reactor are
superimposed over the open-circuit voltage of the welding machine,
causing the arc to ignite.
Important
Increasing the gap between the electrodes at the spark gap
(Fig. 21) results in a higher output voltage; on the other hand, the
frequency of the ignition impulses is reduced.
Adjusting the spark gap: Fig. 21
THIS JOB MAY ONLY BE PERFORMED BY AN ELECTRICIAN
OR BY OTHER SUITABLY QUALIFIED SPECIALIST
PERSONNEL !
1. Switch off machine and unplug from mains!
2. Unscrew the cover and sidepieces of the TIG control unit
3. Unscrew the cover of the ignition device (labelled "CAUTION-
ELECTRIC SHOCK CAN KILL !").
4. Use an insulated screwdriver to short-circuit the spark-gap
contacts (HF adjusting screws) for a few seconds =
CAPACITOR DISCHARGE !
5. Using a 2.0mm Allen key, loosen one of the two fixing screws
on the brass spark-gap holder.
6. - carefully turn the HF adjusting screw clockwise until it
reaches the "zero gap" position.
7. Having done this, turn the HF adjusting screw approx. half a
turn anticlockwise. This automatically creates a sparking gap
of 0,5 - 0,6 mm (Fig. 21).
8. Tighten the fixing screw (use 2 mm Allen key)
9. Check all screw-type and plug-in connections once again.
10. Screw the cover of the HF ignition device back on the right way
round. (Sheet-metal screws with toothed locking washers!)
11. Screw the cover and sidepieces back on
12. Plug the machine back into the mains.
13. Switch on the machine and check that the HF device
is functioning correctly.
Fixing screw
Insulation
Insulating plate
Fig. 21 Spark gap of FHF 5-1 ignition device
Ignition monitoring
If, after fruitless attempts to ignite an arc or after an arc has
broken, the welder forgets to interrupt the control sequence
(2-step or 4-step) by means of the torch trigger, the shielding gas
will normally continue to flow, leading to considerable wastage of
gas. In this case, the monitoring control automatically interrupts
the control sequence after approx. 10 seconds. The operator
must therefore make another attempt to ignite an arc, using the
torch trigger.
0,5 - 0,6mm
Fixing screw
HF-adjusting screw
Spark-gap holder
Fig. 22 FHF 5 -1 ignition device - cutaway view for installation
ASSEMBLING a water-cooled TIG torch
Pull back the sleeve of the torch hosepack (see Fig. 23). Screw
the hexagonal nut (width-across = 21, for current/water return-
flow) onto the current/water connection on the machine, and
tighten it carefully.
Check that an O-ring seal has been inserted in the gas and
water forward-flow connections of the torch.
Screw the knurled nuts of the gas and water forward-flow con-
nections to the appropriately labelled connection points on the
machine, and tighten by hand.
Plug the (9-pole) torch control plug into the machine and latch
it in place.
Before the anti-kink hose-sleeve is pushed back over the
hexagonal nut of the current/water connection, make absolute-
ly sure that this is screwed together tightly.
WARNING!
Before starting up the machine, check the level and quality of
the cooling water. Change or top up as required.
ONLY USE CLEAN TAP WATER!
(see "Putting the cooling unit into operation" p.36)
If the torch is used without there being any coolant, the result
is generally a defect in the torch body or the hosepack!
(No warranty claims accepted!)
Water and current
connection
Water flow
Fig. 23 Torch connection water-cooled
71
Control plug
Control cable
Hose sleeve
Gas hose
Knurled nut
O-ring seal
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