ALFRA ROTABEST 80SP RL-E Mode D'emploi page 17

SPEciAL inFORmATiOn On hAndLing SwiTchABLE
PERmAnEnT mAgnETS
The magnetic surface is located on the underside of the magnetic core drilling machine and generates the
magnetic holding force through magnetic flux when activated. The magnet can be activated independently
from the mains voltage by pressing the lever down. For the magnet to be released, the black safety tab
must be pushed by using the ball of your thumb and pulling the lever upwards. The machine will remain
attached to the workpiece even in the event of a power failure.
material thickness
The magnetic flux of the TML permanent magnet requires a minimum material thickness of 8 mm
(appox. 0.315 inches) to flow completely through the workpiece. If this material thickness is not given,
the maximum holding force is reduced in accordance with the material thickness. Conventional electric
or permanent magnets have a deeply penetrating magnetic field similar to a tree ́s tap roots and
require a large material thickness of more than 25 mm (appox. 0.984 inches) to achieve the maximum
holding force. The compact magnetic field of the TML magnets is similar to shallow roots and achieves
maximum holding force even with low material thickness, so that drilling can be done with sufficient
holding force even on thin sheets of only 3-4 mm (appox. 0.118 to 0.157 inches).
material
The load-bearing capacity of the permanent magnets is determined by using S235 material.
Steel with a high carbon content or whose structure has been changed by heat treatment has a low
holding force. Foamed or pore- flawed cast parts also have a lower holding force.
material
Unalloyed steel (0.1-0.3% C content)
Unalloyed steel (0.3-0.5% C content)
Cast steel
Grey cast iron
Nickel
Stainless steel, aluminium, brass
Surface quality
If an air gap is created between the magnet and the work piece it reduces the holding force. In the same way,
paint, rust, scale, surface coatings, grease or similar substances all form an air gap between the work piece
and the switchable magnet, reducing the holding force.
Temperature
The high-power permanent magnets installed in the TML-magnet irreversibly lose their magnetic
properties at temperatures preceding 80°C (176°F). The full holding force is never reached again even after
the magnets have cooled down.
AdjuSTmEnT OF ROTATiOn SPEEd
The machine has a transmission with four gears and full-wave electronic.
First, you must make the correct mechanical adjustments. Afterwards, you set the rotation speed
with the help of the electrical rotation speed regulator.
If possible, always choose the adjustment with low gear shifting and high engine speed. This way,
the motor is set at a high torque protecting it against overheating due to mechanical overload.
ThERmO PROTEcTiOn
Thermo protection automatically stops the motor when it's overheated. In order to cool the machine
down, let it run with high rotation speed and in neutral for about two minutes.
magnetic force in %
100
90-95
90
45
11
0
17