Tweco PAK 44G - Manual (Page 25)

Manual 0-2686 19 OPERATION
SECTION 4:
OPERATION
4.01 Introduction
This Section provides a description of the Pak 44G Power
Supply operating controls and procedures. Identification
of the Panel Controls is followed by operating procedures.
4.02 Functional Overview
The main components of the Pak 44G Plasma Gouging
System are and their functions are summarized below.
NOTE
Refer to Appendix V for a System Block Diagram.
A. Torch Connections
• Plasma gas, high frequency, and positive (+) power
for the pilot arc flow to the torch through the black
lead.
• Secondary gas (or water) flows to the torch through
the yellow lead.
• Torch coolant and negative (-) power flow to the
torch through the green water cooled lead.
• Coolant return flows through the red and blue wa-
ter cooled lead.
B. Pilot Arc
When the torch is started an arc is established between
the electrode and gouging tip. The pilot arc makes a
path for transferring the main arc to the work.
C. High Frequency
A high voltage, high frequency current is superim-
posed on the direct current to establish and maintain
the pilot arc.
D. Gouging Arc
The main bridge rectifier converts three-phase AC
power to DC for the pilot and main gouging arcs. The
negative output is connected to the electrode through
the torch lead. The positive output is connected to
the workpiece (via the work cable).
E. Current Control
The desired Gouging current is set on the CURRENT
ADJUST knob. A control circuit stabilized gouging
current against fluctuations due to changes in line
voltages, material thickness, torch standoff and travel
speed. This circuit changes the saturating current in
the reactor and the amount of AC power supplied to
the main bridge rectifier.
4.03 Operating Control Descriptions
This sub-section provides specific functional descriptions
of the Power Supply operating controls, indicators and
connections. The Power Supply has a Front Panel, Ac-
cess Panel and Rear Panel. Each panel is described in
this sub-section as to the functions of the connections,
switches, and indicators.
A. Front Panel
A-02101
2
1
10
13
12
6
5
16 15 14
9
11
4 8
3
7
Figure 4-1 Front Panel Description
1. Current Adjust Knob
Adjust knob until desired current is indicated on
Ammeter.
2. Ammeter (AM)
Indicates amperage supplied to torch.
3. Ready Indicator (LT3)
Amber light indicates that the ON/OFF switch is
ON, that lead connections access door is closed
and that pump is running.
4. AC POWER Indicator (LT1)
Red light indicates that primary AC power is be-
ing supplied to the system.
5. PLASMA GAS
Indicates pressure at which plasma gas is being
supplied to the torch.