Tweco Merlin 6000GST Master PS - Manual (Page 17)

Manual 0-2652 2-3 INTRODUCTION & DESCRIPTION
11. Coolant Reservoir Capacity
2 gallons
Capable of handling a total of 150 feet of torch lead length
12. Secondary Water
WARNING
The Optional Water Mist Secondary Flow Con-
trol Assembly must be installed when using water
as the secondary.
Tap water can be used as a secondary gas and must
be capable of delivering the following minimums:
• Water pressure of 50 psi (3.5 bar)
• Flow of 9 gph (40 lph)
NOTES
Tap water should only be used as a secondary gas
on machine torches.
The tap water source does not need to be deionized,
but in water systems with extremely high mineral
content a water softener is recommended.
13. Power Supply Dimensions
Enclosure Only -
Width: 24.12 in (0.61 m)
Height: 38.38 in (0.98 m)
Depth: 34.25 in (0.87 m)
Fully Assembled -
Width: 28.50 in (0.72 m)
Height: 43.38 in (1.10 m)
Depth: 43.75 in (1.11 m)
14. Weight of Power Supply Only
678 lbs (308 kg)
2.04 Theory Of Operation
A. Plasma Arc Cutting and Gouging
Plasma is a gas which is heated to an extremely high tempera-
ture and ionized so that it becomes electrically conductive. The
plasma arc cutting process uses this plasma gas to transfer an
electric arc to a workpiece. The metal to be cut is melted by the
intense heat of the arc and then blown away by the flow of gas.
Plasma arc gouging uses the same process to remove material
to a controlled depth and width.
With a simple change of torch parts, the system can also be
used for plasma arc gouging. Plasma arc gouging is used to
remove material to a controlled depth and width.
B. Input and Output Power
The Power Supply accepts input voltages from 200 to 575V, 50
or 60 Hz, three-phase. Input voltages are set by an internal
changeover in the unit. The unit converts AC input power to
DC power for the main cutting arc. The negative output is
connected to the torch electrode through the negative torch
lead, and the positive output connects to the workpiece through
the work cable.
C. Pilot Arc
When the torch is activated there is a 0.5 second (service ad-
justable) gas pre-flow, followed by a uninterrupted pulsed DC
pilot arc established between the electrode and tip. The pilot
arc is initiated by a momentary high voltage pulse from the Arc
Starter Box. The pilot creates a path for the main arc to transfer
to the work. When the main arc is established, the pilot arc
shuts off. The pilot automatically restarts when the main arc
stops, as long as the torch remains activated (see NOTES).
NOTES
For the arc to restart automatically, AUTO RE-
START must be enabled at switch settings inside
the Power Supply (Refer to Operating Manual 0-
2652, Section 4.07).
For using AUTO RESTART when using oxygen
(O
2
) plasma contact your local distributor.
D. Main Cutting Arc
The Power Supply accepts 50 or 60 Hz three-phase line
input. An internal changeover switches input line volt-
ages in three ranges, for 200/220/230V, 380/415/460V,
or 500/575V operation. The power supply converts AC
input power to DC power for the main cutting arc. The
negative output is connected to the torch electrode
through the negative torch lead. The positive output is
connected to the workpiece via the work cable and ring
lug connection.