How to calculate the force of electromagnet?

1. Magnetism Formula Calculation 

The magnetism of electromagnet can be calculated by the formula B=μoi/(2πr), where B is the magnetic field strength, μo is the constant of magnetic flux in vacuum, i is the magnitude of current, and r is the distance from the electromagnet. When the current is 1 ampere, the magnetic field at 1 meter away from the electromagnet can reach the maximum value, and the magnetic field strength is 4π10^-7 microtesla (T). The magnetic field strength at half a meter away from the electromagnet will reach 16π10^-7 microtesla (T), while the magnetic field strength at 2 meters away from the electromagnet will decrease to 1π10^-7 microtesla (T).

2. What is the relationship between electromagnet current and magnetism

The magnetism of electromagnet is closely related to the current. When the number of turns of the coil is constant, the greater of the current will generate more stronger of the force. When the current passes through the wire, a magnetic field is generated, and the magnetic field generates a magnetic force, which increases the magnetic field of the coil, thereby increasing the magnetism of force accordingly. 

Specifically, when the current passes through the copper coil, the magnetic field in the coil interacts with the current, causing the magnetic field of the electromagnet to gradually increase. When the current is larger, the magnetic force increases faster, and the magnetism of the electromagnet is stronger. This process is similar to the relationship between a magnet and an iron nail. When the magnet and the plunge are in contact, their magnetic fields interact with each other, causing the magnetic field of the magnet to gradually increase.

In addition, the frequency of the current is also related to the magnetic field. The higher the frequency, the greater the magnetic field strength. With the same number of coil turns, the use of high-frequency current will make the magnetic field strength of the electromagnet higher.  In short, there is a close relationship between the current and the magnetism in an electromagnet. The larger the current, the stronger the magnetism of the electromagnet; the higher the frequency, the greater the magnetic field strength of the electromagnet. These factors will affect the magnetism of the electromagnet.

3. Does the electromagnet have residual magnetism?

The electromagnet will retain a certain amount of magnetism after the power is turned off. This residual magnetism is called residual magnetism. The size of the residual magnetism depends on factors such as the diameter of the electromagnet coil, the current size and the operating temperature. In some specific cases, such as the lifting electromagnet is working, a part of the magnetism will still be retained on the workpiece and the lifting electromagnet. This residual magnetism is also called residual magnetism.

Residual magnetism will affect the performance and life of the electromagnet, so it is necessary to pay attention to the problem of residual magnetism when using electromagnets. For example, after turning off the power of the lifting electromagnet, a part of the magnetism will still remain on the workpiece and the lifting electromagnet. At this time, the switch can be turned to the demagnetization position, and the current direction in the coil can be changed several times to remove the residual magnetism to improve the efficiency of removing the working. In addition, when removing a workpiece with a large area, you can first loosen the workpiece with a wooden stick, copper rod or wrench before removing it, or place the workpiece on an insulated material to reduce the influence of residual magnetism.

In short, the electromagnet will retain a certain amount of residual magnetism after the power is turned off. This is the result of the interaction between the magnetic field and current of the coil. When using an electromagnet, you need to pay attention to the problem of residual magnetism to ensure the performance and life of the electromagnet.

4 How to calculate the force of an electromagnet

The force of an electromagnet can be calculated by electromagnetic attraction. Electromagnetic attraction refers to the electromagnetic force acting on the magnetized armature, and its magnitude is proportional to the total area of ​​the magnetic field lines passing through the magnetic poles and the square of the magnetic induction intensity in the air gap. If the magnetic induction intensity is uniform on the surface of the magnetic pole, the basic formula for calculating the electromagnetic attraction is:

Electromagnetic attraction = magnetic induction intensity × air gap length × distance between armature and magnetic pole.  Where μ is the vacuum magnetic permeability, s is the magnetic circuit cross-sectional area (m2), and kf is the leakage coefficient, which is generally taken as 1.2-5. The distance d between the armature and the magnetic pole can be calculated based on the air gap length and the magnitude of the magnetic induction intensity.

In real applications, in order to calculate the force of the electromagnet, it is necessary to know the magnitude and distribution of the magnetic induction intensity, as well as parameters such as the air gap length and the distance between the armature and the magnetic pole. The strength of the electromagnet can be calculated using formulas in physics or computer programs.