Pilot Arc - Lincoln Electric PRO-CUT 60 SVM104-A Service Manual

PILOT ARC

The Pro-Cut 60 has a smooth, continuous pilot
arc. The pilot arc is a means of establishing and
transferring the arc to the work piece for cutting.
The pilot arc current flow is from the positive
potential work terminal through the R2 resistor
and CR2 contacts to the pilot lead circuit in the
torch cable. The pilot current transfers from the
THEORY OF OPERATION
FIGURE E.5 - Pilot Arc
nozzle to the electrode in the torch head and then
on to the torch bulkhead connector, which is con-
nected to the negative potential within the
machine. When the torch head is brought close to
the work piece the pilot arc transfers to the work
surface and the cutting arc is established. This
transition takes place because of the low resis-
tance between the torch electrode and the work
piece.
FIGURE E.6 - Pilot Lead Circuit
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
E-4
PRO-CUT 60