At the heavy steel plate lifting site, the crane moves slowly, but there are no steel cables or hooks below - only an inconspicuous metal plate adsorbing several tons of steel, hanging steadily in the air. Behind this is the power of the magnetic lifter, which uses the "invisible hand" of the magnetic field to completely revolutionize the way heavy materials are transported.

Core principle: precise control of magnetic field

Magnetic lifters are mainly divided into two types: permanent magnet and electromagnetic. The core of both types is to achieve adsorption and release through the control of magnetic field.

- Permanent magnet lifter: It uses high-performance permanent magnet materials such as neodymium iron boron (NdFeB) inside, and changes the distribution of magnetic lines of force by rotating the mechanical handle. When turned on, the bottom forms a longitudinal magnetic pole to adsorb the load; when closed, the magnetic lines of force are closed inside to achieve "zero magnetic leakage" release. The feature of not requiring power makes it extremely safe in power-off scenarios.

- Electromagnetic lifter: It relies on current to pass through the coil to generate a magnetic field, and the size of the magnetic force can be flexibly controlled by adjusting the voltage. The advantage is that it can be remotely controlled and is suitable for accurately separating single pieces of material from stacked plates. However, it requires continuous power supply and a backup battery to deal with the risk of power outages.

- Innovative combination: Electro-permanent magnet technology (such as Magswitch) combines the advantages of both. It only needs to be powered on for a moment to switch the magnetic state, and no power is required to maintain the magnetic force thereafter, with an energy saving rate of 95%, and supports remote control operation.

Why is it the darling of the industry?

1. Safe and reliable:

The maximum pull-off force of the permanent magnet type is 3.5 times the rated load, eliminating accidental falling off; the electromagnetic type avoids the arcing failure of the traditional contactor through contactless control technology (such as thyristor module) and improves stability.

2. High efficiency and energy saving:

Permanent magnets do not require electricity, and electromagnetics only consume electricity when working. Compared with hydraulic or mechanical clamps, energy consumption is reduced by more than 90%, and the cost of the cooling system is eliminated.

3. Lightweight design:

The high magnetic energy product of neodymium magnets reduces the size of the equipment by 50%, and it can be carried by manpower, greatly reducing the load of the crane.

Good maintenance and monitoring can extend the life:

- Avoid impacting neodymium magnets (brittle materials are prone to breakage);

- Check magnetic force attenuation every two years and replace aged magnet modules;

- Electromagnetically check the battery capacity regularly to ensure that the power-off magnetic retention function is effective.