Tweco 300 XT Ultra-Cut Plasma Cutting System - Manual (Page 150)

ULTRA-CUT 300 XT
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The AC Suppression PCB has capacitors and other transient suppression components to protect the system from
transients on the C lines. It also provides power for the neon C present indicators which illuminate when C
power is connected even with ON�OFF switch, CB1, off.
Differences between various models.
uto�Cut �00 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 C �00 XT, for H�O Mist shield. There is a pressure regula�
tor and gauge for each gas inlet and water flow meter/control when the H�O Mist option is used. ll 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 uto�Cut rc 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, RS 1000 XT. In place of the spark gap the RS 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 uto�Cut, uto�Cut XT and the older RS 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/rc Starter that sits on top
of the main enclosure very similar to the GCM 1000 of our earlier uto�Cut models. It is in fact called a GCM 1000
XT. Both uto�Cut XT models have an analog current control (Potentiometer). On the front panel of the main unit
for the C �00 XT and in the upper box, the GCM 1000 XT, for the C 300 XT version. In either case the amperage
setting is displayed on the front panel digital display.
Both uto�Cut models have the gas mode switch on the rear, for the C 300 XT next to the gas inlets of the GCM
1000 XT. On the C �00 XT it’s near the connectors, fuses & circuit breakers. The switch should be set according
to the type of gas, IR/O� or N�, H35 or other non�oxidizing gas, being used for the plasma.
In the C �00 XT the Pilot board is mounted on the upper section of the second inverter module (IM#�) the ½ mod�
ule, in the place of the second or “B” section if it was a full module. The C 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, �00, 300 & �00 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 uto�Cut XT units to detect and prevent operation when
coolant flow is below the minimum of 0.75 GPM (�.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 E�06.
Ultra�Cut XTs have standard consumables for cutting currents lower than those used for uto�Cut XT, 15 vs. 55
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#1).