Welder Operation; Setting The Controls; Auxiliary Power - Lincoln Electric SHIELD-ARC 400AS-50 Operating Manual

WELDER OPERATION

ELECTRIC SHOCK can kill
General
Connect the electrode and ground cables to the studs marked on
the welder output panel. The studs are marked "Positive" and
"Negative". Some types of electrode require electrode positive
and others negative. Therefore consult the instructions for the
particular electrode being used to determine which lead is to be
attached to the "Positive" and which to the "Negative" stud.
When welding at a considerable distance from the machine, care
should be taken that ample size welding cables are used. Small
size cables for long distances reduce output at the point of
welding.

Setting the Controls

The welder is equipped with Dual Continuous Control of the
welding output. To meet the varied requirements of present day
welding it is highly desirable to be able to vary the voltage and
current separately. Dual Continuous Control means that it is
possible to get the proper welding current throughout the range to
the machine in two or more ways.
There are two controls which determine the output of the
generator:
1. Continuous Current Control – to vary the welding
amperage
2. Job Selector – to vary the open circuit voltage of the
generator.
Job Selector
The Job Selector is both the fine current adjustment and the
voltage control of the welder. With this control it is possible to
obtain the exact current necessary. Also by means of this control
the open circuit voltage can be varied to suit different welding
applications.
The Job Selector dial is divided into four sections. The section
marked "Large Electrodes" provides a high open circuit voltage.
The section marked "Normal Welding Range" gives medium high
open circuit voltage. The section marked "Overhead and Vertical"
gives a medium low open circuit voltage. The section marked
"Special Applications" provides a low open circuit voltage and is
used with a minimum setting on the Continuous Current Control.
Continuous Current Control
The Current Control provides the major adjustment of welding
current to suit any particular application. The dial reads
continuously in a clockwise direction from maximum to minimum
and has three graduated concentric dials corresponding to the
respective sections of the Job Selector dial. When the Job
Selector is set on the "Overhead and Vertical" section of its dial,
USE OF WELDERS AS STAND-BY POWER UNITS
FOR ELECTRICALLY
powered equipment
Welders with 240 volt, 50 Hz. auxiliary A.C. outlets can be used
as stand-by power units.
Page 8
the approximate welding current is indicated by the "Overhead
and Vertical" scale on the Current Control dial.
Do not change the Current Control setting while welding.
How to Set the Controls
Assume you want to make a vertical up weld using a 4.0mm
electrode at about 135 amps. A snappy digging arc (medium low
open circuit voltage) is required to give the best control of the arc
in the whipping technique that must be used.
1. Set the Job Selector to the section of the dial marked
"Overhead and Vertical".
2. Set the Current Control to read 135 amps on the scale marked
"Overhead and Vertical".
3. Strike the arc.
4. If the arc is too weak, move the Job Selector counter-clockwise
to increase the current. If a still higher current is desired, turn
up the Current Control 10 or 20 amps. In the final adjustment,
be certain the Job Selector is still set in the same range to get
the snappy arc recommended for vertical welding.

Auxiliary Power

These machines are fitted with two standard 3 pin 240 volt 15
amp auxiliary power outlets and two 3 pin 115 volt auxiliary power
outlets. Auxiliary power is available while welding - refer Table
below for relative loadings. Both 240 volt and 115 volt supplies
can be used simultaneously, provided the total current drawn
does not exceed the current in the Table. The outlets are located
on the control panel of the 400AS-50. Total power available is
Welder Output (Amps)
300 or less
300-350
350-400
400-450
5,000 watts, 240 volt, 50 Hz. A.C. at 100% duty cycle or 2,500
watts, 115 volt, 50 Hz. A.C. at 100% duty cycle.
Important: The 400AS-50 auxiliary power circuits are not
connected to the welder frame, and earth leakage protection is
not required (refer AS2790-1989, Clause 6.1.9.(a) and Comment
1), however connected equipment should be double insulated, or
fitted with an effective earth wire.
Notwithstanding the above, should a Residual Current
Device (RCD) be fitted to this machine, it is imperative that
the frame of the machine be earthed in accordance with
AS3000, Clause 5.6. An effective earth is essential for the
safe operation of machines fitted with RCD devices.
To avoid the possibility of electric shock and/or damage to the
welding machine, connections and alterations must be made by a
licensed electrician, who can determine how the machine can be
adapted to the particular installation and comply with the local
Supply Authority regulations.
It is also important that an adequately rated isolation switch is
used to ensure that the stand-by power unit and the Authorities'
Supply are not connected on parallel.
Shield-Arc 400AS-50
FOR ELECTRICALLY
powered equipment
Maximum permissible
Auxiliary Power Load (Amps)
WARNING
20
15
10
5
IMA 554C