General Description; Duty Cycle - ESAB LHI 425 Manual Do Usuário E Pecas De Reposicao

2) DESCRIPTION

2.1) General description

The LHI Rectifiers are power sources with characteristics of simultaneous current intended for welding with
stick electrodes. They can also be used for welding with the TIG process due to its vast current range.
They allow carbon steel welding, alloy steel, stainless steel, cast iron, aluminun and its alloys, copper and
bronze.
The welding current is set using the potentiometer in the panel or in the optional remote control for any
application within the use range.
In the LHI's equiped with digital instrument, it keeps the voltage and current values after the welding is over.
It´s possible to weld electrodos up to 6,0mm.
The LHI´s rectifiers equipment body are strong and easily moved in the working area. The trolley has a
brake and also lifting eyes.
The power trigger circuit of the thyristor maintain the welding current constant comparing the real current
signal with the pre-defined current signal, irrespective of load variation in the main supply voltage up to
± 10%.This signal comparison does not permit that an overloading happens limiting the welding current.

3) DUTY CYCLE

The duty cycle refers to the time period in which the welding machine can supply a certain maximum
welding current (loading time) and a reference time, according to international regulations. The time
reference is of 10 minutes.
The 60% nominal duty cycle means that the machine can supply simultaneously its nominal welding current
during periods of 6 minutes (loading); each period must be followed by a resting period (the machine does
not supply welding current) of 4 minutes, that is, (6 + 4 = 10 minutes) simultaneously, and not exceeding the
internal temperature limit of the components, according to their design and project.
This guide line and guidance applies to any duty cycle value.
In the LHI Rectifier the duty cycle allowed increases up to 100% once the welding current used decreases,
inversely, the duty cycle allowed decreases once the welding current increases up to the maximum current
range.
The chart 4.1 shows the authorized loading for the LHI Rectifier.
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LHI 425