Tweco 150XL CE PAK Master Without Latch Circuit - Manual (Page 33)

Manual 0-2727 4-7 OPERATION
4. In continuous cutting applications using CO2, it is of-
ten necessary to manifold four to six cylinders together
to maintain adequate flow at operating pressures.
B. Fold Back Feature
Should the torch tip contact the workpiece or molten
slag, the output current will immediately drop to 35
amps to minimize potential tip damage.
4.07 Optional Power Supply
Settings
The following functions can be used to tailor a system for
special application requirements or unique user prefer-
ences. These functions are controlled by DIP switches
located on the Logic Control PC board in the power sup-
ply.
Remove the left side panel and locate the Logic Control
PC Board near to top center of the unit. Set the function
as required.
A. High/Low Speed Auto-Restart Function
(SW5)
The Plasma Power Supply is always in the Auto-Restart
mode. This means that at the end of the cut, if the START
signal is still on, the pilot will restart automatically.
An immediate pilot restart, when cutting over holes or
expanded metal at relatively slow speeds, may cause the
arc to transfer back to the piece just cut. This happens
because the torch has not had time to be moved away
from the cut piece and results in extra starts and unnec-
essary parts wear.
The High/Low Speed Auto-Restart switch, SW5, has two
settings as follows:
• Low Speed - adds a one-tenth second delay to the
pilot restart to prevent arc back conditions.
• High Speed - no delay required as it may delay
starting on the next edge.
A-02258
Logic PC Board
SW5
1 2
Figure 4-7 High/Low Speed Auto-Restart Switch
SW5 Location
Select the desired function as shown in the following
chart:
High/Low Speed Auto-Restart Function
Speed SW5-1 SW5-2
High 0 (OFF) 0 (OFF)
Low * 1 (ON) 1 (ON)
* = Factory Setting
NOTE
The ON position is in the direction of the arrow on
the PC Board next to the switch.
B. Gas Pre-Flow Delay (SW3)
The pre-flow delay allows time for gases to flow to the
torch when the torch is activated. Pre-flow is immedi-
ately followed by pilot arc initiation. Gas Pre-Flow De-
lay is set depending on the total torch lead length used
in the system. All power supplies are factory set at 2 sec-
onds and must be reset either to 3.4 or 4 seconds as re-
quired if total torch lead length in the system is over 60 ft
(18.3 m).