Application Cases

Experiment Name: Design of a Respirable Magnetic Core Based on Vector Magnetic Circuit Theory

Experiment Content:Calculation of the magnetic reluctance and magnetic flux density of the respirable magnetic core.

Research Direction:Magnetic Flux Density and Vector Magnetic Circuit Theory

Testing Equipment:ATA-L8 Acoustic Power Amplifier, Signal Generator, Temperature Monitor, Voltage Probe, Power Analyzer, Current Probe, Waveform Recorder, etc.

Figure: Schematic Diagram of the Respirable Magnetic Core Design Based on Vector Magnetic Circuit Theory

Figure: Magnetic Cores with Different Aperture Diameters

Experiment Process:Three sets of magnetic cores with different aperture diameters were prepared, including a solid magnetic core, a magnetic core with a 5 mm diameter aperture, and a magnetic core with a 15 mm diameter aperture. These three sets of magnetic cores are identical in size and electromagnetic parameters, as shown in Figure 1. Two magnetic cores are assembled to form a closed magnetic circuit, securely fastened with zip ties to ensure tight contact of the mating surfaces and minimize the effect of air gaps, as shown in Figure 2. Both the primary and secondary windings are wound around the center column and fixed with high-temperature insulating tape. Additionally, three measurement points are set on the closed magnetic circuit to monitor the magnetic core temperature during the experiment, ensuring that the magnetic core temperature remains constant throughout each test to reduce errors.

Experiment Results:

Figure: Experimental Results

With the magnetic flux amplitude maintained at approximately 0.00018 Wb, the magnetic flux frequency was gradually changed from 20 Hz to 20 kHz, and the experimental results for the different magnetic cores are shown in Figure 3. At lower magnetic circuit frequencies, the magnetic flux distribution is relatively uniform. However, due to the presence of an aperture in the center of the magnetic core with an opening, the effective cross-sectional area for magnetic flux is reduced, thereby increasing the equivalent magnetic reluctance of the magnetic circuit. Therefore, below 10 kHz, the magnetic core with a 15 mm diameter aperture requires more magnetomotive force (MMF) to produce the same amount of magnetic flux as the solid magnetic core. However, due to the skin effect on magnetic flux, which affects the magnetic circuit parameters, the equivalent magnetic reluctance of the solid magnetic core increases with increasing magnetic circuit frequency, leading to an increase in magnetic impedance. In comparison, the magnetic core with an open structure has a certain degree of suppression of the magnetic flux skin effect, resulting in smaller fluctuations in magnetic reluctance with frequency changes. Thus, when the frequency exceeds 10 kHz, the magnetic core with a 15 mm diameter aperture requires less MMF to produce the same magnetic flux compared to the solid magnetic core.

Power Amplifier Recommendation:ATA-L Series Acoustic Power Amplifiers

Figure: Specifications of the ATA-L Series Acoustic Power Amplifiers

Xi’an Antai Electronics is a high-tech enterprise specializing in the research, development, production, and sales of electronic measurement instruments such as power amplifiers, high-voltage amplifiers, power signal sources, preamplifiers for micro-signals, high-precision voltage sources, and high-precision current sources. It provides users with competitive testing solutions. Aigtek has become a widely recognized supplier of instruments and equipment in the industry, with a broad product line and considerable scale. Sample units are available for free trial.