ESAB Migmaster 275, Instruction Manual

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F. Connect the gas hose to the R-33-FM-580 Flowmeter
Regulator and adjust to 25 - 35 CFH.
G Set Migmaster 275 voltage tap switches to RANGE and
FINE ADJUSTMENT VOLTAGE settings desired.
H. Turn on the Migmaster 275’s power switch and begin
seam Mig welding.
If the optional Burn Back module is installed, the MT-250SG
and the ST-23A gun may be operated using these optional
features, see Section 4.2.3.
4.2.3 optIonal Burn BacK MoDule
This optional control module provides an adjustable Anti-Stick
feature to select various burnback times to prevent wire from
sticking in the puddle after a weld.
This delay time, controlled by the “anti-stick” potentiometer, is
variable from approximately 0.05 seconds to 0.5 seconds. The
required delay time generally depends on the WIRE SPEED
Adjustment setting on the front panel - the higher the setting,
the faster wire will feed into the weld, and the more delay time
will be required.
If, when using the Anti-Stick feature, the welding wire tends
to stick in the puddle at the end of a weld, the Anti-Stick time
should be increased; if, on the other hand, the wire burns back
into the torch tip, the anti-stick time should be decreased.
Setting the anti-stick time to “Min” effectively cancels the
anti-stick feature.
4.2 process setup
4.2.1 stanDarD MIg seaM WelDIng W/
gunMaster 250
Refer to Sections 4.3.1, 4.3.2, 4.3.3, 4.3.4, and Table 4.3.3.
4.2.2 st-23a spool-on-gun control
connectIon/operatIon
The Migmaster 275 is equipped with a built-in control for the
Spool Gun which operates via the amphenol control receptacle
and power adaptor, p/n 37301, that provides Gas and Power. The
ST-23A Torch (see Section 2.4.3) has a amphenol-plug control
cable connection, and a gas/power cable, see Figure 4.2.2.
To operate the unit with the ST-23A Torch connected, do the
following (refer to Fig. 4.2.2):
A. Place the Standard/Spool Gun selector toggle switch
(4.1.6) in the 275 to its Spool Gun position.
B. Connect the ST-23A control cable amphenol to the
receptacle labeled CONTROL on the 275’s front panel.
C. Connect the ST-23A gas/power cable to the power
adaptor P/N 37301 using a counter-clockwise rotation.
(see Section 4.1.3).
D. Connect the power adapter to the 275’s Positive Flat
Electrode receptacle
E. Connect the work cable assembly to the negative output
receptacle and attach to the welding work piece.
sectIon 4 operatIon
figure 4.3 electrode posistive flat slope
4.2.4 DutY cYcle (figure 4.5)
The duty cycle of the equipment is the percentage of a 10
minute period which it can operate safely at a given output
current. The Migmaster system is rated at 50% duty cycle.
This means that the equipment can be safely operated at
250 amperes for five minutes out of every 10. This cycle can
be repeated indefinitely (See Figure 4.5).
OPTIONAL
DIGITAL METER
MODULE
OPTIONAL
BURN BACK
MODULE
fig. 4.5 Duty cycle curves
Duty Amps
20 305
295
30 285
(35) 275
40 265
255
50 245
235
60 225
219
70 214
208
80 203
197
90 191
186
100 180
(RATED OUTPUT)
100
125
150
175
200
225
250
275
300
325
20 30 (35) 40 50 60 70 80 90 100
% DUTY CYCLE
WELDING
AMPERES