Arc Machines 207 - Manual (Page 67)

MODEL 207A AND 207A-1
OPERATION MANUAL
Doc. No. 740044
Rev F
SECTION VII - CALIBRATION
7.4 SYSTEM FAULT CORRECTIONS
6. STUB OUT - This fault will only occur when an arc is present and will no
longer exist when the arc goes out. If the arc voltage gets too low or the
electrode should touch the weld puddle then a fault will occur. It creates an
ALL STOP but does not operate the “return to home” function after
Postpurge.
The operator should check to see if the electrode is stuck to the tube being
welded. Clear the obstruction and jog the rotor to the open position.
Remove the tube and replace the electrode, then press the C key to clear the
fault.
Check the required tungsten length and arc gap required for the weld.
Something caused the arc gap to get too small. This FAULT can be “turned
OFF” by use of the SET UP screens, see section 5.6.2. It is recommended to
turn it OFF when MANUALLY welding.
7. HIGH VOLTS - If the arc voltage should get too high during a weld sequence
this fault will occur. It usually occurs if a hole should be made in the weld
and the arc can extend over to the opposite side of the weld. Check the weld
procedure and arc gap required for the weld. This FAULT can be “turned
OFF” by use of the SET UP screens, see section 5.6.2.
It is recommended to turn this OFF when MANUALLY welding or when
using large Arc Gaps (0.050”) and low current in HELIUM or HELIUM
mixed gases. These conditions tend to create very high Arc Voltages and
could cause an undesirable FAULT if this option is left ON.
8. BAD START - If for any reason the M-207A cannot achieve a stable Arc at
the end of PREPURGE the system will display this statement.
There can be several reasons for this to occur. The most common are poor
cable, ground and electrode connections, bad gas, bad tungstens, dirty
tungstens, etc. Another extremely common cause of BAD START is too short
of a PREPURGE time . The RF starter charges during prepurge and too short
a time will cause the RF starter to fire when not fully charged. The RF is
transmitted from the M-207A to the electrode, if anything creates resistance or
an alternate path for the RF the start can be weak.
7.8