Section 5 − Operation; Controls - Miller Millermatic 251 Owner's Manual

5-1. Controls

5
.
This unit has three automatic timers included in its operation to
help save contact tips, gas, and wire:
Tip Saver − Weld output shuts off if tip is shorted to work surface.
Safety shut-off − Weld output will shut off if no arc is detected within 3
seconds after gun trigger is depressed.
Jog mode − When loading a new roll of wire or if the gun trigger is
accidentally pressed, gas will shut off after 1 minute and wire will shut off
after 2 minutes saving wire and gas.
OM-1326 Page 22
SECTION 5 − OPERATION
4
3
1 Voltage Control
Turn control clockwise to increase
voltage.
2 Wire Speed Control
Turn control clockwise to increase wire
feed speed.
JOG Mode
If the trigger on either gun is held for
more than 3 seconds without striking
1
an arc, the unit will automatically shut
off weld power (and shielding gas
output on MIG gun only), but will feed
wire continuously at the preset wire
feed speed (which may be faster or
slower than Run−in Speed) until trigger
is released.
Run−in Wire Feed Speed Settings
Run−in settings for the MIG and Spool
Guns are independently set and stored
in unit memory. The settings are in
2 percent of the welding wire feed speed
preset. Both settings are adjustable
from 25 to 150 percent.
MIG Gun Run−in is factory set at 100%
which is recommended for most wire
sizes and types.
Spool Gun Run−in is factory set at 50%
which is recommended for .030 & .035
wire. A Run−in setting of 25% is
recommended for .047 wire.
To check Run−in settings, start with
the power switch OFF. Press and hold
the MIG or Spool Gun Trigger while
turning the power switch ON. The unit
will power up with both the displays
888
reading , then the voltage display
will read −−− and the wire feed display
will read the preset Run−in percentage
from memory for the gun selected. To
return to the weld
making a change, simply release
trigger and pull the trigger again
momentarily (one second).
To change Run−in settings, start with
the power switch OFF. Press and hold
the MIG or Spool Gun Trigger while
turning the power switch ON. The unit
will power up with both the displays
888
reading , then the voltage display
will read −−− and the wire feed display
will read the preset Run−in percentage
from memory for the gun selected. To
change the Run−in value, release the
trigger and turn the wire feed control
knob (or the wire feed adjustment knob
located on the bottom handle of the
spool gun) to the desired setting for the
selected gun. To return to weld mode
after the Run−in speed change, pull
the trigger momentarily (one second).
3 Power Switch
4 Voltmeter
5 Wire Feed Speed Meter
mode without
Ref. 205 637