Overview
ELMAG20A Air Gap Electromagnet
The Electromagnet ELMAG20A can generate strong magnetic fields for different experimental applications up to 2.2 Tesla. Depending on the magnetic fluctuations density and the equipment that is under test the air gap can be adjusted continuously. The magnet poles come with conical shape close to the test volume to improve accessibility and to optimize the achievable magnetic flux density. It comes with levers for easy use.
The electromagnet AGEM 5520 is usually operated in the non-linear range of permittivity when high fieldstrengths are required. This leads to a more flat characteristic of the magnetic flux density with increasing drive current, the iron of the poles become saturated.
In general, the achievable magnetic flux density between the poles becomes larger with decreasing air gap spacing. The sharp bend of saturation is more pronounced the shorter the air gap is. Enlarging the air gap leads to a "linearisation" of the magnetizing curve, but the acievable flux density reduces. The performance of the magnet is mainly limited by the losses of the copper windings. These losses are proportional to the square of drive current flowing through the coil. A water cooling of the coils was not provided because of economic reasons. Because of the very large thermal capacity of the magnet it can be operated with 5 kW power for 2 minutes, which rises the temperature from 20°C to 60°C. Afterwards a cooling time of approx. 30 min to 1 hour is needed to bring the coils close to room temperature. The cooling time can be reduced significantly when using fans to get rid of the heat.
