Page 25
Issue 08/2013
iMAPLA system description
Function description
The
i
MAPLA system transmits an opposite voltage (negative nominal
voltage) after the “release” command until the current in the lifting magnet is
zero (“demagnetisation with countervoltage”).
The lifting magnet still has a residual magnetism until the current reaches
zero. For this reason, the entire load may not have been released under
certain circumstances.
To release the remaining load, re-magnetisation in the opposite direction
takes place (the voltage polarity is rotated) until reaching half the saved
nominal current. Afterwards, demagnetisation takes place again. This
procedure is carried out a total of 5 times with the current halving each time.
Ö
Fig. 3, Characteristic curve “release”, page 25
The magnetic field is reduced to zero and the full load that is magnetised by
the lifting magnet is released. This is referred to as “sequence pulsation”.
Magnetic force
(corresponds to the
flow of current)
Automatic demagnetisation with
countervoltage and sequence pulsation
Normal demagnetisation
Release
Time
Fig. 3 Characteristic curve “release”
