35
EN
Functional principle
Idling, Accelerat
-
ing
Braking-system components under the side guard pa
-
nel
Braking-system components inside the housing
Idling
When the unreeling device is idling (i.e. when no wire is being fed), the “lever + drawback
pulley” unit (1) is in the bottom position.
This position results from the wire spool’s “running on” after the previous braking operation.
Make sure that the “lever + drawback pulley” unit (1) is not resting on the bottom mechan
-
ical limit-stop, as this would mean that it would no longer be applying any tension to the
welding wire.
If the “lever + drawback pulley” unit (1) remains sufficiently far away from the bottom me
-
chanical limit-stop, this ensures that there is sufficient tensile load on the wire even when
the unreeling device is idling.
Accelerating
Right at the very beginning of the welding operation, the wirefeeder unit starts feeding the
wire at the required wirefeed speed.
Because the wire spool takes rather more time to reach the required rotation speed, the
“lever + drawback pulley” (1) unit rises, releasing sufficient welding wire as it does so.
At the same time, the braking lever (3) is moved by means of the spring (2) and the damper
(8). The brake block (4) is raised, and the wire spool can accelerate.
Throughout the time during which the spool is accelerating, the “lever + drawback pulley”
unit (1) moves upwards. As long as the peripheral speed of the spool has not yet reached
the wirefeed speed, this ensures that the extra amount of wire needed is released.
(6)
(3)
(11)
(12)
(5)
(4)
(2)
(1)
(8)
Summary of Contents for VR 4040
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Page 34: ...34 More details on mounting the end of wire watchdog 2 mm...
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