Thermal Arc 300GTSW Pro-Wave, Service Manual

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pro-wave 300gtsw
June 21, 2012 2-7
2.09 Duty Cycle
The duty cycle of a welding power source is the percentage
of a ten (10) minute period that it can be operated at a
given output without causing overheating and damage to
the unit. If the welding amperes decrease, the duty cycle
increases. If the welding amperage are increased beyond
the rated output, the duty cycle will decrease.
!
WARNING
Exceeding the Duty Cycle Ratings will cause
the Thermal Overload Protection Circuit to
become energized and shut down the output
until the unit has cooled to normal operating
temperature.
Continually exceeding the Duty Cycle Ratings can cause
damage to the welding power source.
To calculate duty cycle:
Art # A-06105
(rated current)2 x (rated duty cycle)
(desired duty cycle)
current =
i.e. At the 300A rated output current, and 25% rated duty
cycle, the operator wants to work on a 50% duty cycle.
The maximum allowable current draw is:
90,000 x (0.5)
current =
45,000
current =
current = 212.1A
Art # A-06106
(300A)2 x (.25)
(.50)
current =