Fronius VST 247, Operating Instructions Manual

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15
ENGLISH
Press the sheets tightly together
Surface of workpiece is too dirty
Spot-welding time is too short
Increase the wirefeed speed Wirefeed speed is too low
Using the respective dials, alter the Intermittent
welding time t1 and Intermittent pause time t2 Intermittent welding time t1 and / or Intermittent
pause time t2 are not set correctly Intermittent welding delivers unsatisfactory
welding results
Spot-welding power is too low Shift the step-switch to a higher setting (consider
using CO
2
as the shielding gas)
Lengthen the spot-welding time by adjusting the
spot-welding time dial
The fuse or miniature c.b. used is too weak, or is
of the wrong type Mains fuse or miniature circuit-breaker
trips when torch trigger is pressed Use fuses specified in the Technical Data, or a
miniature c.b. with a "U" characteristic
Clean the surfaces of the sheets to be welded
Sheets not always resting snugly on one another
Check the earthing cable and clamp Poor earth connection or complete break in earth
connection
Current cable in the welding torch is faulty Replace the hosepack
Main contactor or step switch is faulty Change the contactor or step switch
Torch and hosepack become very hot Respect the duty cycle and loading limits and/or
use a more powerful type of torch Design dimensions of torch are not sufficient for this
task, or duty cycle has been exceeded
Operating-mode selector switch does not
function Control system or switch are faulty Change the MR25A
Fault Cause Remedy
In spot welding, the quality of the weld-
spots is variable
Insufficient penetration in spot welding