Page 14
P30U Instruction Manual Revision : 1
1st December 2006
5.2 Power Up Procedure
NOTE
.
As this plasma power unit does not have a voltage stablised power supply, a fluctuation in the input voltage
will directly affect the output current. This may not be noticeable if the input voltage rises slightly above the
norm as it will provide more power for cutting. If the rise is excessive, consumable life may suffer. However,
when the input voltage falls, the output power also falls, affecting both the pilot arc and main arc. In these
circumstances it will be necessary to adjust the air pressure regulator to reduce the airflow to obtain a
stable pilot arc, and readjust it when the mains voltage returns to normal.
Having completed the mains and cutting earth wiring, connected the torch and checked the fan
rotation, and connected the supervisors panel, the machine is ready for use.
Switch the machine on and after allowing time for the water to circulate through the torch, press the
reset button on the front panel or supervisors panel. The red indicators should go out and the ready light
will illuminate. Note that the supervisors panel will always need to be reset, even if the machine has been
reset on the front panel.
To ascertain the absence of air leaks, the air regulator should be wound fully clockwise and the
pressure gauge should indicate a back pressure in excess of 3 bar.
It is now necessary to adjust the air pressure to give the highest possible reading consistent with good
arc starting and a stable pilot arc, this should be at least 0.7 bar. Switch on the torch with the nozzle well
clear of any workpiece, person or equipment, and re-adjust the air pressure until it is at maximum or the
pilot arc becomes unstable (very noisy, misfire, and the voltmeter showing 300 volts). At this point reduce
the pressure to restore stability (arc less noisy, stable arc, and the volt meter showing 250/300 volts).
Always maintain as high an air pressure as possible for pilot arc as this gives the best consumable life.
The output neon is “on” and the voltmeter reads between 250 vdc and 300 vdc at this stage.
The machine is now setup and is now ready to be used. Before starting a cut please see section 1 for
safety information and then section 5.3 for cutting procedure. The correct procedure for cutting underwater
is considered more fully in the Supervisors Panel Instructions