Page 12
P30U Instruction Manual Revision : 1
1st December 2006
Hose Connections
See section 4. Connecting the torch to the power unit.
Voltmeter
Indicates the arc voltage.
Typical values would be: Power applied to torch but no arc
300v (actually off-scale: up to 350V)
For Pilot Arc
250 to 300 volts
For Main Arc
150 to 200 volts
(Voltage is affected by supply voltage, cutting depth, cutting speed and material thickness)
Output ON LAMP
Indicates that power is applied to the torch.
Reset Button
Resets earth current, earth safety, and water warning circuits.
Air Pressure Gauge
Displays the back pressure in the system during the pilot arc and cutting modes
Typical values would be: For Pilot Arc
0.7 to 2.2 bar (10 to 30 psi)
For Main Arc
2.4 to 3.4 bar (35 to 50 psi)
Note that the air regulator tracks the working depth, therefore the pressure gauge shows this operating
pressure plus the working depth (1 bar = 10m = 32 ft)
Tracking Air Regulator
Sets the air flow through the torch to give a stable pilot arc and adjusts to allow for the working depth.
Note that essential indicators on the front panel, and the reset button, are replicated on
the supervisor’s panel, and it is normally only necessary to switch the machine on or off
at the power unit.
Note that the supervisor’s panel and the dual earth system must be used before it is
possible to energise the torch.
It is possible to use the machine in a conventional mode for dry cutting in the workshop (ie single
earth and control by torch switch) by use of a special bypass plug fitted to the supervisor’s remote
control socket. If supplied this should not normally be kept with the machine to prevent use in
inappropriate circumstances. It should never be used when operating underwater