Explain the concept of electrical magnetic hysteresis.
1 Answer
Electromagnetic hysteresis is a phenomenon that occurs in ferromagnetic materials when they are exposed to changing magnetic fields. It is characterized by the lagging of the material's magnetic properties behind the applied magnetic field, creating a loop-like pattern on a graph known as a hysteresis loop. This phenomenon is of significant importance in various applications, such as transformers, electric motors, and magnetic storage devices.
To understand electromagnetic hysteresis, let's break down the key concepts:
Ferromagnetic Materials: Ferromagnetic materials are substances that exhibit strong magnetic properties when exposed to an external magnetic field. Common examples include iron, nickel, and cobalt. These materials consist of tiny regions called magnetic domains, where the atomic magnetic moments align in the same direction. In their natural state, these domains are randomly oriented, resulting in a net magnetization of zero.
Magnetization Curve: When a ferromagnetic material is subjected to an external magnetic field, the magnetic domains start to align with the field direction. As the intensity of the magnetic field (magnetic flux density) increases, the material's magnetization also increases, and the material becomes magnetized. The relationship between the magnetic field strength (H) and the resulting magnetization (B) is depicted on a graph called the magnetization curve or B-H curve.
Hysteresis Loop: If the magnetic field strength is gradually increased and then decreased, the material's magnetization doesn't follow the same path on the B-H curve. Instead, it forms a closed loop known as a hysteresis loop. This loop represents the relationship between the magnetic field strength and the magnetization during both the magnetization (increasing field) and demagnetization (decreasing field) processes.
Remanence and Coercivity: At the top of the loop (high magnetic field), the material reaches a maximum magnetization called remanence (Br). Even when the external field is removed, the material retains some residual magnetization. To completely demagnetize the material, a reverse magnetic field needs to be applied. The strength of the reverse field required to reduce the residual magnetization to zero is known as coercivity (Hc).
Energy Loss: As the magnetic domains switch orientations during the cycling of the magnetic field, energy is dissipated within the material due to the friction-like motion of domain boundaries. This energy loss results in heat generation and reduces the efficiency of magnetic components.
Electromagnetic hysteresis has both practical implications and uses. For instance, in electrical transformers, hysteresis losses contribute to the inefficiency of energy transfer. Engineers and scientists work to minimize hysteresis effects by selecting appropriate materials and designing magnetic components that operate within the desired range of magnetization and field strength.
To understand electromagnetic hysteresis, let's break down the key concepts:
Ferromagnetic Materials: Ferromagnetic materials are substances that exhibit strong magnetic properties when exposed to an external magnetic field. Common examples include iron, nickel, and cobalt. These materials consist of tiny regions called magnetic domains, where the atomic magnetic moments align in the same direction. In their natural state, these domains are randomly oriented, resulting in a net magnetization of zero.
Magnetization Curve: When a ferromagnetic material is subjected to an external magnetic field, the magnetic domains start to align with the field direction. As the intensity of the magnetic field (magnetic flux density) increases, the material's magnetization also increases, and the material becomes magnetized. The relationship between the magnetic field strength (H) and the resulting magnetization (B) is depicted on a graph called the magnetization curve or B-H curve.
Hysteresis Loop: If the magnetic field strength is gradually increased and then decreased, the material's magnetization doesn't follow the same path on the B-H curve. Instead, it forms a closed loop known as a hysteresis loop. This loop represents the relationship between the magnetic field strength and the magnetization during both the magnetization (increasing field) and demagnetization (decreasing field) processes.
Remanence and Coercivity: At the top of the loop (high magnetic field), the material reaches a maximum magnetization called remanence (Br). Even when the external field is removed, the material retains some residual magnetization. To completely demagnetize the material, a reverse magnetic field needs to be applied. The strength of the reverse field required to reduce the residual magnetization to zero is known as coercivity (Hc).
Energy Loss: As the magnetic domains switch orientations during the cycling of the magnetic field, energy is dissipated within the material due to the friction-like motion of domain boundaries. This energy loss results in heat generation and reduces the efficiency of magnetic components.
Electromagnetic hysteresis has both practical implications and uses. For instance, in electrical transformers, hysteresis losses contribute to the inefficiency of energy transfer. Engineers and scientists work to minimize hysteresis effects by selecting appropriate materials and designing magnetic components that operate within the desired range of magnetization and field strength.