Lifting Magnets – Advantages and Disadvantages of 3 Main Types
As mentioned in our last blog, there are mainly 3 types of magnets that can be used for lifting of steel materials: permanent lifting magnets, electric lifting magnets and electro-permanent lifting magnets. Here, we’re going to make a comparison of their pros and cons of each type.
Disadvantages of Permanent Lifting Magnet
As this type of magnets are made of hard materials and are permanently magnetized, the strength of the magnetic field line is constant. And because of that, permanent lifting magnets tend to corrode with time. The strength of the maximum magnetic field is, thus, reduced. You cannot vary the poles of the permanent magnet.
On the long run, the permanent magnet would always loose some of its magnetic property after several operations ending up with a dysfunctional system. In addition, we can produce the magnetic field of a permanent magnet ONLY below a certain temperature. Therefore, we cannot use this type of magnets for hot-device applications.
Disadvantages of Electric Lifting Magnet
As electromagnets need a power source to get energized, and require a continous supply of current during work, they tend to get hot due to current flow through the windings. That is to say, electric lifting magnets take a lot of energy to use and will heat up very fast. If cranked up to high it could be dangerous. This may, at some point in time, affect the magnets and its field due to various factors like ohmic heating, Inductive voltage spikes, core losses, the coupling of coils, etc. Moreover, there is radiation that comes from electromagnetism.
Disadvantages of Electro-Permanent Lifting Magnet
As an electrically controlled or switched lifting magnets, electro-permanent lifting magnet’s magnetic flux penetrates not far away from its poles. And it’s very sensitive to the air gap between the magnet and the load to be lifted. The lifting capacity decreases dramatically as the air gap increases. Therefore, electro-permanent lifting magnet should not be good for some loads which have UNEVEN or ROUGH surface. Beside, it costs a bit more than permanent and electro magnets.
Advantages of Permanent Lifting Magnet
It doesn’t require electrical supply during the handling of the load; no danger of dropping the material if there is a power failure and can be used when electricity is not readily available.
Advantages of Electric Lifting Magnet
As a device which releases magnetic field with a continuous electrical supply, the strength can be increased by connecting it to a higher volt battery or charger, which is to say it offers the potential of much higher lifting capacity. It can also generate a much deeper magnetic field than permanent magnets enabling them, for example, to penetrate through several plates in a stack. The greater depth of field makes them generally more tolerant of a small air gap.
Advantages of Electro-permanent Lifting Magnet
Electro-permanent lifting magnets are featured with the following: energy saving – only use power during activation and deactivation for a few seconds; higher safety – can remain holding of the load even in a power failure; remote control available; magnetic force can be selectively managed for specified operation; maintenance free.
To sum up, each type of lifting magnets has its pros and cons. Understanding their perspective advantages and disadvantages can help us choose a more appropriate magnetic lifter to best suit the loads and working environments.
Electro-permanent Lifting Magnet Manufacturer
HVR MAG focuses on the R&D of electro-permanent magnetic technology and offers versatile magnetic solutions for various industrial applications, including lifting magnets, magnetic mold clamping systems, workholding magnetic chucks, magnetic grippers for robots.
Featured with Higher Safety and Energy Saving, all our magnetic products and systems are custom designed by our engineers after mutual communications with clients, to best fit their lifting needs and requirements. Contact us for more information.
