MK Products Cobramatic II - Manual (Page 13)

Cobramatic ® II Owner's Manual - Page 6
established, and, even if the trigger is held ON or released, the cycle will end
at the spot timer time out. To initiate a new cycle, the trigger must be turned
OFF (released) and re-triggered. The spot time knob must be clicked ON and
the duration may be set from .07 to 3 seconds. The spot time may be used
with all other functions; pre-purge, burn-back, post-purge.
NOTE: Even with the spot timer turned "ON", the wire will not time out
until you strike an arc. This provides very accurate, repetitive timing.
C
ONTROLS FOR
O
PTIONAL
M
ETER
K
IT
(P/N 005-0190)
The LED meter provides a continuous reading of wire feed speed in inches
per minute. When the trigger is energized, the meter will display weld voltage.
P
OSA
S
TART
O
PERATING
P
ROCEDURE
G
ENERAL
D
ESCRIPTION
The Posa Start feature allows the Cobramatic ® II to be used in combination
with constant current DC welding power sources of open circuit voltage in
excess of 55 volts - also, any constant voltage welding power source capable
of a minimum of 50 amps.
NOTE:
Reverse polarity MUST be used.
The Posa Start MUST be used with a Constant Current power source to
provide arc initiation and may be used with a Constant Voltage power supply
to help eliminate burn-backs at arc start.
CAUTION:
DO NOT OPERATE A Cobramatic ® II ON A POWER SOURCE HAVING A HIGH-
FREQUENCY STARTING CIRCUIT BEFORE MAKING SURE THAT THE HIGH-
FREQUENCY PORTION OF THE POWER SOURCE IS TURNED OFF. FAILURE
TO TAKE THIS PRECAUTION WILL CAUSE PERMANENT DAMAGE TO THE
POSA START CIRCUITRY.
The Posa Start Run-in Speed Control, located on the front panel, provides
adjustment for slow wire run-in. Once the arc has been established, the
wire feed speed is automatically changed from the slow run-in speed to the
welding speed. The Posa Start does not control the wire speed while welding.
CV P
OSA
S
TART
O
PERATION
Attach Cobramatic ® II to CV power source according to the installation
instructions.
Turn the Cobramatic ® II to the “ON” position and the Posa Start to the “OFF”
position.
Adjust power source to desired voltage for your weld condition.
Depress gun trigger and adjust wire feed speed to match voltage setting. If
approximate wire feed is not known, it is better to start with excess wire feed
rather than too little, in order to prevent a “burn-back”.
Turn the Posa Start switch to the “ON” position. Press torch trigger and, using
Run-in Speed Control, adjust wire feed rate to approximately 10% of the
welding wire speed.
Strike an arc, and adjust wire feed rate at gun until correct condition is
achieved.
CC P
OSA
S
TART
O
PERATION
Attach the Cobramatic ® II to a CC power source according to the installation
instructions.