Tweco 130i Transarc Service Manual - Manual (Page 22)

SAFETY AND INSTALLATION 3-4 Manual 0-5282
TRANSARC 130i
3.05 High Frequency Introduction
The importance of correct installation of high frequency
welding equipment cannot be overemphasized.
Interference due to high frequency initiated or stabilised
arc is almost invariably traced to improper installation.
The following information is intended as a guide for
personnel installing high frequency welding machines.
!
WARNING EXPLOSIVES
The high frequency section of this machine
has an output similar to a radio transmitter.
The machine should NOT be used in the
vicinity of blasting operations due to the
danger of premature firing
!
WARNING COMPUTER
It is also possible that operation close to
computer installations may cause computer
malfunction.
3.06 High Frequency Interference
Interference may be transmitted by a high frequency
initiated or stabilised arc welding machine in the
following ways.
1. Direct Radiation: Radiation from the machine can
occur if the case is metal and is not properly grounded.
It can occur through apertures such as open access
panels. The shielding of the high frequency unit in
the Power Source will prevent direct radiation if the
equipment is properly grounded.
2. Transmission via the Supply Lead: Without
adequate shielding and filtering, high frequency energy
may be fed to the wiring within the installation (mains)
by direct coupling. The energy is then transmitted by
both radiation and conduction. Adequate shielding and
filtering is provided in the Power Source.
3. Radiation from Welding Leads: Radiated interference
from welding leads, although pronounced in the vicinity
of the leads, diminishes rapidly with distance. Keeping
leads as short as possible will minimise this type of
interference. Looping and suspending of leads should
be avoided wherever possible.
4. Re-Radiation from Unearthed Metallic Objects: A
major factor contributing to interference is re-radiation
from unearthed metallic objects close to the welding
leads. Effective grounding of such objects will prevent
re-radiation in most cases.
3.07 Electromagnetic Compatibility
WARNING
Extra precautions for Electromagnetic
Compatibility may be required when this
Welding Power Source is used in a domestic
situation.
A. Installation and Use - Users Responsibility
The user is responsible for installing and using the
welding equipment according to the manufacturer’s
instructions. If electromagnetic disturbances are
detected then it shall be the responsibility of the user
of the welding equipment to resolve the situation with
the technical assistance of the manufacturer. In some
cases this remedial action may be as simple as earthing
the welding circuit, see NOTE below. In other cases it
could involve constructing an electromagnetic screen
enclosing the Welding Power Source and the work,
complete with associated input filters. In all cases,
electromagnetic disturbances shall be reduced to the
point where they are no longer Trouble-some.
NOTE
The welding circuit may or may not be
earthed for safety reasons. Changing the
earthing arrangements should only be
authorised by a person who is competent to
assess whether the changes will increase the
risk of injury, e.g. by allowing parallel welding
current return paths which may damage the
earth circuits of other equipment. Further
guidance is given in IEC 974-13 Arc Welding
Equipment - Installation and use (under
preparation).
B. Assessment of Area
Before installing welding equipment, the user shall make
an assessment of potential electromagnetic problems
in the surrounding area. The following shall be taken
into account.
1. Other supply cables, control cables, signaling and
telephone cables; above, below and adjacent to the
welding equipment.
2. Radio and television transmitters and receivers.
3. Computer and other control equipment.
4. Safety critical equipment, e.g. guarding of industrial
equipment.
5. The health of people around, e.g. the use of pace-
makers and hearing aids.