What is more, it is possible to increase the number of magnets magnetized in the same amount of time, because energizing the capacitors to a lower voltage takes less time. Measurements were conducted using a model teslameter made by F. Lee in his article deals with the magnetization of an axially oriented eight-pole epoxy-bonded Nd-Fe-B magnet. Magnetic, electric, electromagnetic and electromechanical devices need permanent magnets with different numbers and configurations of magnetic poles. The simulated time course of magnetic induction in the middle of the coil is presented in Figure 7. Measurements of currents in the coil for impulse magnetization were compared with PSpice calculations.
This can be mainly seen in magnets with a large volume. Multipolar magnetization of a planar and cylindrical permanent magnet with 36 magnetic poles resembling a chess-board was developed. Figure 3 shows the measurements of remanence and coercivity of a sintered Nd-Fe-B permanent magnet as a function of the magnetization field strength. This type of magnetizing fixture is air-cored and 24 kA peak currents are produced [ 17 ]. For this voltage, the magnetic flux density on the edge of the magnet is equal to 3. Hydraulic laboratory 70 m2 with several engineering teaching equipment for filtration, coagulation, sedimentation processes.
The magnetization direction was parallel to the anisotropy direction. Analysis of Impulse Magnetization of Nd-Fe-B Magnet Next a series of numerical calculations were conducted in PSpice software, which is an electric circuit simulator that uses the magnetier parameters of elements, such as resistance, inductance and capacitance.
The main field of application for this type of permanent magnet are electric machines such as electric motors and generators. The differences between the measurement curve and the simulation curve are caused by inaccuracy in determining parameters such as the resistance maynetizer the aluminium tube R 2inductances L 1 and L 2and mutual inductance M.
The permanent magnets were thermally demagnetized after each measurement cycle. They often produced, depending on the resistance of the magnetizing fixture, oscillating currents which in a second pulse causes demagnetization of the weries [ 6 ]. In turn, the magnetization of an axial eight-pole magnet was analyzed in [ 1516 ], and six-pole in [ 17 ].
The course of the current from upper Figure 6 was implemented in FEM software as the source of magnetic field. For example, in direct iimpulse motors permanent magnets are applied in stators as an excitation source of magnetic field. These parameters were essential for subsequent analyses with PSpice software.
Magnet magnetization in a mounted motor is difficult also because of the existence of bulk soft magnetic materials in a motor. The curves in Figure 6 show that the magnetic induction increases more slowly than the current and decreases for longer than the current.
These steps led to the determination of the supply parameters that enable magnetization of the magnet to saturation in the whole volume, imoulse only on the surface. Because of the high resistivity of the magnet, impulse eddy currents in this magnet were neglected [ 19 ].
What is more, it is possible to increase the number of magnets magnetized in the same amount of time, because energizing the capacitors to a lower voltage takes less time. This can mechanically and thermally spoil the magnetization fixture earlier than expected.
The analysis of the impulse magnetization process of permanent magnets made of sintered Nd-Fe-B alloys was conducted in several steps. Magnetization of an eight-pole planar Nd-Fe-B ring bonded magnet was analyzed and a magnetizing fixture for this magnet was designed and applied.
Simulation of Capacitor Discharge Magnetisation. Journal List Sensors Basel v. A simulation of magnet magnetization was also conducted in-situ in the vicinity of soft magnetic materials, so the current required was not as high as in an air-core magnetizing fixture. The mwgnetizer pump is composed of two rotating steel discs with embedded permanent magnets with alternating poles. With the development of magnetic materials the range of their application is broadening, among others in magnetic sensors.
The same authors conducted magnetization and measurements of electric parameters. FEM s imulations of magnetic induction in the centre of an Nd-Fe-B magnet as magnetizef function of capacitor voltages. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. Higher voltages do not increase the saturation of the magnet, but rather just cause higher energy costs, and a longer process of magnetization due to energizing of the capacitors and higher heating of the magnetization coil.
This is caused by eddy currents induced in the aluminium shell of the coil.
The magnetizing fixture was designed and manufactured by Wroclaw University of Technology. Improvements in and Relating to Magnetising Apparatus. Measurements of the demagnetization curves are presented in Figure 1 b and Figure 2. This tube is paramagnetic and is sufficient for the mechanical safety of the coil. Figure 3 shows the measurements of remanence and coercivity of a sintered Seeries permanent magnet as a function of the magnetization field strength.
Figure 2 shows the results of measurements of the second quadrant of the hysteresis loop of an Nd-Fe-B permanent magnet with different magnetizing field strengths. Impule of a fully mounted motor is difficult and full saturation is hard to obtain because of the insufficient capacitance of the capacitors [ 1314 ].
The simulated time course of magnetic induction in the middle of the coil is presented in Figure 7. R 2 and L 2 represent the resistance and self-inductance of the aluminium tube. The SMC material enabled uniform magnetization of the core and the lack of displacement of maggnetizer flux from the magnetic core [ 1620 ].
Permanent magnets are also used in electromagnetic flow meters for liquid metals. Conflicts of Interest The authors declare no conflict of interest. Improved magnetizers were applied from [ 7 ]. The design and analysis of axial field multipole impulse magnetizing fixtures. Measurements confirming the numerical calculations and parameters of the electrical supply are determined optimally.
The magnetization fixture consists of an internal copper coil with turns of 3 mm diameter wire and an external tube of aluminium with a diameter serids mm and 4 mm thickness to ensure high strength against high impulse currents and forces.
The magnetization of a bush magnet with four radial poles was analyzed in [ 11121314 ]. Main laboratory 70 m2 for water chemical and microbial analyses, Hydraulic laboratory 70 m2 with several engineering teaching equipment for filtration, coagulation, sedimentation processes. R 1 and L 1 represent the resistance and self-inductance of the coil.