Tweco 200 XT Auto-Cut 380V - Manual (Page 30)

AUTO-CUT 200 XT
3-� INSTALLATION Manual 0-5253
0 - 10 ft (0 - 3 m) Ideal
20 ft (6 m) Maximum
1/0
Ground Cable
Customer Supplied
Auto-Cut
Power Supply
‘Star’
Ground
Earth Ground
Rod
CNC
Device
Torch
Cutting Table
Cutting Machine / Gantry
Auto-Cut XT System
Art # A-11553
1/0 Ground Cable
(F1)
1/0 Work Cable
3.06 Ground Connections
A. Electromagnetic Interference (EMI)
Pilot arc starting generates a certain amount of electromagnetic interference (EMI), commonly called RF noise. This
RF noise may interfere with other electronic equipment such as CNC controllers, remote controls, height controllers,
etc. To minimize RF interference, follow these grounding procedures when installing mechanized systems:
B. Grounding
1. The preferred grounding arrangement is a single point or “Star” ground. The single point, usually on the cutting
table, is connected with 1/0 AWG (European 50 mm 2 ) or larger wire to a good earth ground (measuring leass
than 3 ohms; an ideal ground measures 1 ohm or less. Refer to paragraph ‘C’, Creating An Earth Ground. The
ground rod must be placed as close as possible to the cutting table, ideally less than 10 ft (3.0 m), but no more
than 20 ft (6.1 m) from the cutting table.
NOTE
All ground wires should be as short as possible. Long wires will have increased resistance to RF fre-
quencies. Smaller diameter wire has increased resistance to RF frequencies, so using a larger diameter
wire is better.
2. Grounding for components mounted on the cutting table (CNC controllers, height controllers, plasma remote
controls, etc.) should follow the manufacturer’s recommendations for wire size, type, and connection point loca-
tions.
For Thermal Dynamics components it is recommended to use a minimum of 10 AWG (European 6 mm 2 ) wire or
flat copper braid with cross section equal to or greater than 10 AWG connected to the cutting table frame. The
connection point must be to clean bare metal; rust and paint make poor connections. For all components, wires
larger than the recommended minimum can be used and may improve noise protection.
3. The cutting machine frame is then connected to the “Star” point using 1/0 AWG (European 50 mm 2 ) or larger
wire.