Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 170)

ULTRA-CUT 400 XT
A-46 APPENDIX Manual 0-5306
Differences between various models.
Auto-Cut 200 or 300 XT units use the basic gas control/arc start circuits consisting of single gas inlets, one for Plasma, one for
Gas Shield and one for water inlet, optional for AC 200 XT, for H2O Mist shield. There is a pressure regulator and gauge for each
gas inlet and water flow meter/control when the H2O Mist option is used. All 3 are turned on/off with control solenoids. Changing
gas types requires connecting different gasses to the rear panel and setting the gas switch on the rear panel to match the plasma
gas type. There is no separate pilot (Preflow) gas at this time.
The Auto-Cut Arc starter is the conventional spark gap type with water cooled coil that we’ve used for several years. This arc
starter injects the HF onto the torch electrode via the negative lead with the return via the tip and pilot lead. The Ultra-Cut XT units
use the remote arc starter, RAS 1000 XT. In place of the spark gap the RAS 1000 XT uses a solid state ignition module to create
the HF pulses which are injected onto the tip and return via the electrode, the opposite direction of that used in the Auto-Cut,
Auto-Cut XT and the older RAS 1000 used with the Ultra-Cut units.
The AC 200 XT had the gas control and arc starter built into the main enclosure in the area that is used for the top inverter module
in other units of this family. The AC 300 XT has a separate gas control/Arc Starter that sits on top of the main enclosure very
similar to the GCM 1000 of our earlier Auto-Cut models. It is in fact called a GCM 1000 XT. Both Auto-Cut XT models have an
analog current control (Potentiometer). On the front panel of the main unit for the AC 200 XT and in the upper box, the GCM 1000
XT, for the AC 300 XT version. In either case the amperage setting is displayed on the front panel digital display.
Both Auto-Cut models have the gas mode switch on the rear, for the AC 300 XT next to the gas inlets of the GCM 1000 XT. On
the AC 200 XT it’s near the connectors, fuses & circuit breakers. The switch should be set according to the type of gas, AIR/O2
or N2, H35 or other non-oxidizing gas, being used for the plasma.
In the AC 200 XT the Pilot board is mounted on the upper section of the second inverter module (IM#2) the ½ module, in the
place of the second or “B” section if it was a full module. The AC 300 XT and all Ultra-Cut XT models have the Pilot board on the
opposite side from the inverters, the “circuit breaker” side, in the upper rear behind the CCM module. Refer to the Replacement
Parts section of the manual for illustrations showing the locations.
Ultra-Cut XT units, 100, 200, 300 & 400A units all can use either the GCM 2010 “manual” Gas control or the DFC 3000 Auto Gas
Control. These gas controls remain unchanged from earlier Ultra-Cut units.
Ultra-Cut XT units use the same flow switch, FS1, as the Auto-Cut XT units to detect and prevent operation when coolant flow is
below the minimum of 0.75 GPM (2.8 l/m). However, the Ultra-Cut XTs include a coolant flow sensor, FL1, which also measures
the flow and can detect if there are gas bubbles in the coolant which can reduce consumable part life. Detecting bubbles or low
flow from FL1 will NOT prevent cutting but will show a code as a warning that something is not right. The code is E406.
Ultra-Cut XTs have standard consumables for cutting currents lower than those used for Auto-Cut XT, 15A vs. 55A as well as
marking at lower currents. To improve operation at these lower currents an additional output inductor, L1, is added in series
with the 1st inverter section (IM#1A).
Status codes.
The codes for the power supply are displayed on the Display PCB 4 digit numerical display. Some codes refer to the Gas Controls
but more detailed Gas Control codes will be found on the individual gas controls. The gas controls used with the XT family of
plasma supplies have not changed. They have their own set of status codes which should be covered in another section. This
guide assumes you have first considered the Status Code Tables in the Operation Section of the unit manual. Individual codes
will point to different inverter sections while this guide groups similar codes together. For example code E (or L) 249 indicates
an inverter fault in Inverter 2A. This guide covers codes 247-252 in one section as they are all the same, varying only by which
inverter and section they refer to.
The codes are separated into 6 groups.
Group 1 Plasma Process -- Relating to pilot, transfer, torch voltages, etc.
Group 2 Plasma Power Supply -- Primarily the Inverter Sections
Group 3 Interface to Gas controls -- Mainly the DFC 3000
Group 4 Cooling System -- The liquid cooling system for the torch and inverters
Group 5 CCM -- Communications port to the gas controls