Thermal Dynamics ULTRA-CUT 200 XT, Operating Manual

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ULTRA-CUT 200 XT
Manual 0-5304 INSTALLATION 3-9
4. Assemble the transformer and power resistor in a metal box. Connect a 3 wire (w/gnd) power cord with ground wire attached
to the metal box for safety. If a plastic box is used instead, connect the transformer core and the resistor mounts to the power
cord ground wire. There should be a fuse ¼ - ½ A, in series with the transformer primary. From the transformer secondary
connect one wire to the utility safety ground. This could be the cutting table frame, the ground terminal of the 120 or 220 VAC
outlet or the test box if grounded as indicated.
An excellent ground measures 1 ohm or less. Up to 3 ohms is often acceptable, higher reduces the effectiveness of the EMI
suppression.
0.1 VAC = 1 OHM,
0.3 VAC = 3 OHM,
etc.
Triad N-68X
Utility (building) GND
11
5 V
AC
220 VAC
GND
Triad N-68X
F
F
11
5 V
AC
11
5 V
AC
11
5 V
AC
11
5 V
AC
GND
120 VAC
R = 1.2K, 15W
(2.2K, 25W for 220 VAC)
Ground Rod with other
connec
ti ons removed
Art # A-12710
5. Increasing the ground rod length beyond 20 - 30 ft (6.1 – 9.1 m) does not generally increase the effectiveness of the ground
rod. A larger diameter rod which has more surface area may help. Sometimes keeping the soil around the ground rod moist
by continuously running a small amount of water into it will work. Adding salt to the soil by soaking it in salt water may also
reduce its resistance. You may also try a chemical ground rod devise. When these methods are used, periodic checking of
the ground resistance is required to make sure the ground is still good.
E. Routing Of Torch Leads
1. To minimize RF interference, position torch leads as far as possible from any CNC components, drive motors, control cables,
or primary power lines. If cables have to pass over torch leads, do so at an angle. Do not run the plasma control or other
control cables in parallel with the torch leads in power tracts.
2. Keep torch leads clean. Dirt and metal particles bleed off energy, which causes difficult starting and increased chance of RF
interference.