GTS iMAPLA series - Overload Protection Imapla; Fig. 4 Characteristic Curve, Overload Protection

Issue 08/2013 Page 26
MAPLA- Modular energy supply system for load lifting magnets
iMAPLA system description
Function description
4.4.3 Overload protection iMAPLA
The intelligent MAPLA system (iMAPLA system) has asophisticated
protection system which provides secure protection to the machine,
generator control electronics, load cables and plug connection components
against overcurrent caused by faults or excessive magnetic loads.
Magnetic
voltage
230V DC
max.
permissible
rated current
of MAPLA
Energisation
phase
Measurement-
and test phase
(teaching phase)
static state
Time t(sec)
The reduced output voltage
protects the generator and the
electronics system from
overloading
The iMAPLA system limits the
magnetic current
standard overloaded system
Fig. 4 Characteristic curve, overload protection
Thanks to the intelligent measurement procedure in the energisation
phase, the characteristic data for the magnet are recorded and calculated.
The iMAPLA system veries the connected magnetic load during the
measurement and test phase. If the lifting magnet exceeds the maximum
rated output of the machine, the magnetic voltage will be reduced and the
magnetic current adjusted to anominal value. This is usually equivalent
to the maximum current congured for the machine. This measurement
procedure is repeated continuously during the working process. When the
magnet warms up during the cyclic energisation, the electrical resistance
of its coils will increase, which leads to areduced rate of power input. The
system intelligently increases the magnetic voltage in order to move the
system to the maximum possible range of capacity/maximum current.
This safety function makes it possible to connect precisely adjusted sizes of
magnet (lifting magnets corresponding to the rated power of the system).
If the magnetic coil is very cold, the operation of an overload is safely
controlled. The system is secured against partial short circuits of magnet
windings or faults of the load.