Electromagnetic simulation of Duffing lock - QuickField simulation example
Duffing's electromagnetic lock is a kind of electromagnet used to permanent attraction of magnet keeper and it fast releasing when additional coil will be energized.
A holding coil is constantly supplied with properly chosen current that saturates relatively thin iron core in the surroundings of releasing coil. If additional current flows there, a magnetic field will be significantly reduced. If the force of keeper attraction is comparable with the force of the spring, even small demagnetizing current will release the magnet keeper.
How to find electromagnetic lock pulling force?
Answer Typical applications Geometry
Model depth 50 mm.
Given
Results
Engineering question
Set up a plane-parallel QuickField DC Magnetics problem for an electromagnetic lock and evaluate pulling force from computed field results.
electromagnetic locking devices, security latch actuators, solenoid locking mechanisms
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Simulation problem
Problem Type
Plane-parallel problem of DC magnetics.
Holding coil total (n*I)h = 100 kA-turns;
Releasing coil total current (n*I)r = 50 kA-turns;
Force of stretching spring f = 250 N/m
Core and keeper iron magnetic permeability - nonlinear:
When releasing coil is not energized (I=0, edlock_1 case) then the force of keeper attraction is about 295 N/m. Otherwise (I>0, edloc_2 case) the attraction force decreases to 225 N and becomes less then stretching force of the spring, and magnet keeper will be unlocked. The force was calculated by means of "Integral calculator" tools.
Ih, A·turns
Ir, A·turns
F, N/m
100000
0
295
100000
50000
225
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