Advanced Welding Processes: Technologies and Process Control

Table 3.2 Features of various power source designs
Power source type
Conventional tapped
transformer–rectifier,
moving iron, variable
inductor, magnetic
amplifier etc.
SCR phase control
Transistor series
regulator
Primary rectifier–
inverter
Hybrid and
secondary chopper
Output characteristics
Fixed at design stage,
slow response rate, no
mains voltage
stabilisation
Electronically variable
within response limits
of switching system.
Mains stabilised but
high ripple especially at
low output
Very fast response,
flexible control,
waveform control,
accurate, ripple free,
repeatable
Fast response, variable
output, stable and
repeatable
Fast response, variable
output, stable and
repeatable
Electrical efficiency
Fair – but
magnetising
current and
thermal losses in
transformer
Fair
Poor
Very good
Very good
Physical characteristics
Relatively heavy and
industrial duty units are
large but robust and
reliable
May be more compact
than conventional design
due to reduction of
magnetic (wound)
components
Fairly large, may be
water cooled
Compact – electronically
complex
Medium size, air cooled
Relative
cost
1
4
6
3
4
Applications
Manual GMAW, MMAW,
GTAW. Hobby units and
general purpose
fabrication
Manual and mechanised
GMAW/GTAW and
manual MMAW. Medium
to high quality
fabrications
High quality mechanised
and automated GMAW
and GTAW. Precision
engineering and R&D
Medium to high quality
manual and automated,
multiprocess
Medium to high quality
manual and automated,
multiprocess
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Advanced welding processes