Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 29)

ULTRA-CUT 400 XT
Manual 0-5275 INSTALLATION 3-7
3.08 Ground Connections
0 - 10 ft (0 - 3 m) Ideal
20 ft (6 m) Maximum
1/0
Ground Cable
Power Supply
‘Star’
Ground
Earth Ground
Rod
See
Manufacturer
CNC
Device
Torch
Cutting Table
Cutting Machine / Gantry
3/0 Work Cable
Remote Arc
Starter (RAS-1000)
Star Ground on Cutting Table
Note: The gas control module can
be mounted on top of the power
supply.
If it is, it should be grounded
directly to the power supply with
#4 AWG ground, (F).
Any location requires grounding
the power supply to the
‘Star’ ground with the 1/0
Ground Cable (F1).
Gas Control Module
Primary location
#4 AWG
Ground
(F)
Customer supplied
1/0
Ground Cable
(F1)
Art # A-11875
1/0 Ground Cable
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 less 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 frequencies. 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 locations.
For Thermal Dynamics components (except Remote Arc Starter and Gas Control Module) 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 Remote Arc Starter uses 1/0 earth ground wire and the Gas Control Module should use minimum #
4 AWG wire. 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.
4. The plasma power supply work cable (see NOTE) is connected to the cutting table at the single point “Star” ground.
NOTE
Do Not connect the work cable directly to the ground rod. Do not coil up excess ground or power cables. Cut to
proper length and reterminate as needed.
5. Make sure work cable and ground cables are properly connected. The work cable must have a solid connection to the cutting
table. The work and ground connections must be free from rust, dirt, grease, oil and paint. If necessary grind or sand down