GTS iMAPLA series - Release Load (Switch off Lifting Magnet); Fig. 2 Characteristic Curve, Lifting

Issue 08/2013 Page 24
MAPLA- Modular energy supply system for load lifting magnets
iMAPLA system description
Function description
Magnetisation is completed alot earlier and the lifting magnet reaches its
maximum tension force much earlier. Once the saved current value has been
reached, the voltage is reduced to the rated value. As aresult, the current in
the lifting magnet remains constant until the load is released.
Ö Fig. 2, Characteristic curve, “lifting”, page24
Magnetic force
(corresponds to the
ow of current)
Quick magnetisation
with impulse excitation
Normal magnetisation
without impulse excitation
Lifting
Time
Fig. 2 Characteristic curve, “lifting”
4.4.2 Release load (switch o lifting magnet)
During standard demagnetisation, the magnetic current also falls slowly, like
an exponential function. The residual magnetism which persists for along
time means the lifting magnet needs arelatively long time to release the
entire load.
Ö Fig. 3, Characteristic curve “release”, page25
To accelerate the demagnetisation, the iMAPLA system uses an automatic
demagnetisation process with countervoltage and sequence pulsation.
This method also uses the reference current measured before starting for the
rst time.