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Idiomas disponibles
Idiomas disponibles
Surface quality
The maximum holding force of a lifting magnet is the result of a closed magnetic circuit in which the magnetic field
lines can connect up freely between the poles, thus creating a high magnetic flow. In contrast to iron, for example,
air has very high resistance to magnetic flow. If a kind of "air gap" is produced between the lifting magnet and the
workpiece, this reduces the holding force. In the same way, paint, rust, scale, surface coatings, grease or similar
substances all form a gap, or an air gap, between the workpiece and the lifting magnet. The increasing surface
roughness or unevenness of the surface also has a negative effect on the holding force. Reference values can be
found in the performance table of your lifting magnet.
Load dimensions
When working with large workpieces such as girders or plates, the load can sometimes become deformed during
the lifting process. A large steel plate would bend downwards at the outer edges and create a curved surface which
is no longer in complete contact with the underside of the magnet. The resulting air gap reduces the maximum
load-bearing capacity of the lifting magnet. In contrast to this, nor should objects be hollow or smaller than the
magnet gripping surface, as otherwise the entire power of the load-lifting magnet will not be used.
Load alignment
During load transport care must be taken that the lifting magnet is always at the centre of gravity of the workpiece
and that the load, or lifting magnet respectively, is always aligned horizontally. In this load situation, the magnetic
force on the lifting magnet acts with its full pull-off strength at right angles to the surface and results in the
maximum specified load-bearing capacity through the 1:3 standard safety factor. If the workpiece with the lifting
magnet moves from the horizontal position to a vertical position, the lifting magnet is operated in shearing mode
and the workpiece can slip away to the side. In shearing mode, the load-bearing capacity is reduced through the
friction coefficient of the two materials.
Temperature
The high-power permanent magnets installed in the lifting magnet irreversibly lose their magnetic properties from a
temperature of more than 80°C, so that the full load-bearing capacity is never reached again even after the magnet
has cooled down.
Please note the specifications on your product or in the operating manual.
Maintenance and inspection of the lifting magnet
The user is obliged to maintain and service the lifting magnet in compliance with the specifications in the operating
manual and according to the country-specific standards and regulations (e.g. ASME B30.20B, BGI 556; AMVO).
The maintenance intervals are classified according to the frequency with which the maintenance should be carried
out. If one of the faults listed should occur, please proceed as follows:
Before every use...
check the lifting magnet for visible signs of damage
clean the surface of the workpiece and the underside of the magnet
free the underside of the magnet of rust, chips or unevenness
check the blocking function of the safety tab on the lever
Weekly...
check the lifting magnet and load hook for deformation, cracks or other defects
check that the operating lever and safety tab are working properly
check the load hook for damage or wear and have it replaced if necessary
check the underside of the magnet for scratches, pressure points or cracks and have the magnet repaired
by the manufacturer if necessary
Monthly...
check the markings and labelling on the lifting magnet for legibility and damage and replace if necessary
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