ESAB Heliarc 250 Instruction Manual page 5

SECTION 1
1.1 Introduction
The Heliarc 250 / welding power sources are con-
AC DC
stant current AC/DC welding power sources for high
quality tig and stick welding in both the AC and DC mode.
The unique characteristics of the magnetic and solid state
circuits provide excellent arc conditions for all tig welding
as well as high alloy stick electrodes. The non-saturating
current limiting reactor and electronic feedback control
prohibits high current surges inherent with saturable
reactors or solid state SCR control alone, therefore re-
ducing spatter on stick electrodes as well as tungsten
spitting when tig welding. The electronic firing circuit
utilizes a voltage compensating circuit which compen-
sates for line voltage variations of +/-10 percent.
Through its unique design, the Heliarc 250
bines all of the latest state-of-the art magnetic and solid
state concepts to provide the wide range volt-ampere
curve characteristics needed for a constant current AC/
DC power source - see Figure 1-1. Refer to Table 1-1 for
technical specifications.
Table 1-1. Specifications
Rated Output @
40% Duty Cycle
Open Circuit Voltage
Output Welding Current
Current Low Range
Range in High Range
Amperes
Input Voltage AC
Input Current @
without P.F.C.*
Rated Load in
Amperes ¹
with P.F.C.*
Power Factor @ without P.F.C.*
Rated Load
with P.F.C.*
Auxiliary Power Output
Dimensions: Width
Depth
Height
Weight
* P.F.C. indicates with or without power factor correction
¹ The input currents listed are for balance control in the "max. clean" (0) position.
When balance control is set in the "max. penetration" (10) position, input current
will increase approximately 40%.
1.2 Duty Cycle
Duty cycle is defined as the ratio of load time to the total
time. Standard current ratings are based on a 10-minute
cycle. This machine is rated at 40 percent duty cycle
which means the rated load (250 amps.) is applied for a
/ com-
AC DC
250 Amps @ 30 Volts
AC/DC, Tig/Stick
79 Volts AC/72 Volts DC
AC/DC
5 to 60 Amps
15 to 320 Amps
(20 to 320 Amps*)
208/230/460 V, 1P, 60 Hz
208 V 230 V 460 V
107 96 48
83 74 37
Approx. 52%
Approx. 76%
115 V AC, 15 Amp, 60 Hz
16 in. 406 mm
30 in. 762 mm
22 in. 559 mm
380 lbs 171 kg
(295 lbs 179 kg*)
1-1
total of 4 minutes and shut off for a total of 6 minutes in a
10-minute period. However, if the welding current is
decreased, the duty cycle can be increased. Conversely,
if the welding current is increased, the duty cycle must be
decreased. Figure 1-2 enables the operator to determine
the safe output of the power source at various duty cycles.
Note that the duty cycle of the unit without p.f. is approx-
imately 50% less (25% less on unit with p.f.) when
Balance Control is in the "max. penetration" position.
Figure 1-1. Volt-Ampere Curves
Figure 1-2. Duty Cycle Chart
DESCRIPTION
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