Thermion BRIDGEMASTER, Owner'S Manual

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4.6 Air Sweep/Inch*
The air sweep is for cleaning dust from the surface prior to arc spraying. The air is turned
on with the trigger switch located on the spray head. When partially depressing the
trigger switch the air will turn on, holding that position, the air will spray without feeding
wire. The spray operation begins when the trigger switch is further depressed.
* Capabilities to inch the wire feed is provided at the feeder. The inch mode feeds wire
with all other functions inactive.
4.7 Wire Runback
The wire runback feature creates a gap at the wire's end to aid arc starting. When the
spraying is stopped, the wires are retracted on the end of the stopping sequence. A
potentiometer (adjustment) located on the electrical panel determines the amount of
runback. Turning the potentiometer clockwise increases the amount of runback time.
The runback time should be adjusted to create a 1/8" to 1/4" (3.2-6.4 mm) gap. Because
of the wire liner length and change in shape on the job, the amount of runback can vary
with the increase in resistance in the liners. If the wires fail to gap, quickly actuating the
trigger (on and off) will recycle the runback timer and provide the gap necessary for arc
starting.