Tweco 200 XT Ultra-Cut Plasma Cutting System - Manual (Page 68)

ULTRA-CUT 200 XT
4-4 OPERATION Manual 0-5273
WARNING
AC power is still present inside the unit.
• Fans and pump as well as all indicators turn off.
• The display may show a fault code for a moment, this is a normal part of shutting off power and does not
indicate a fault.
b. Open (turn off) the main power disconnect. All power is now removed from the unit.
• Rear panel AC indicator turns OFF.
Operational Suggestions
1. Wait four minutes before setting the ON/OFF switch to OFF after operation. This allows the cooling fans to run
to dissipate operating heat from the power supply.
2. For maximum parts life, do not operate the pilot arc any longer than necessary.
3. Use care in handling torch leads and protect them from damage.
4. When using water as the shield note the following:
• Use clean drinking quality tap water to help prevent particulate build-up within the system water shield
plumbing.
• Particulate contamination and build-up can cause reduced consumable parts life and premature torch failure.
• A cartridge type particulate water filter may help achieve optimum cutting performance.
4.03 Gas Selection
A. Plasma Gases
1. Air Plasma
• Most often used on ferrous or carbon base materials for good quality at faster cutting speeds.
• Air plasma is normally used with air shield.
• Only clean, dry air is recommended for use as plasma gas. Any oil or moisture in the air supply will
substantially reduce torch parts life.
• Provides satisfactory results on nonferrous materials.
2. Argon/Hydrogen (H35) Plasma
• Recommended for use on 3/4 in (19 mm) and thicker stainless steel. Recommended for 1/2 inch (12 mm)
and thicker nonferrous materials. Ar/H2 is not normally used for thinner nonferrous materials because
less expensive gases can achieve similar cut quality.
• Poor cut quality on ferrous materials.
• Provides faster cutting speeds and high cut quality on thicker materials to offset the higher cost.
• A 65% argon / 35% hydrogen mixture should be used.
3. Oxygen (O2) Plasma
• Oxygen is recommended for cutting ferrous materials.
• Provides faster cutting speeds.
• Provides very smooth finishes and minimizes nitride buildup on cut surface (nitride buildup can cause
difficulties in producing high quality welds if not removed).
4. Nitrogen (N2) Plasma