Lifting Magnets - Knowledge Base
Working Principles of Permanent Lifting Magnets
Permanent lifting magnets are composed of magnet materials and steel parts which build a path
through which the magnetic flux goes from the magnet materials to ferromagnetic load to be
NL-B series permanent
lifting magnets are assembled with high grade Neodymium magnets and
mild steel in order to get high magnetic power and compact sizes.
A NL-B permanent lifting magnet has two magnetic
sources, one is in the main body and another is in the rotor. When
the two magnetic sources are at same magnetic direction the lifting
magnet project magnetic flux to a ferromagnetic load underneath its
poles. In contrast, when the two magnetic sources are at opposite
magnetic direction they absorb each other’s energy and no magnetic
flux can go out from the lifting magnet. Meanwhile, the lifting
magnet has no attraction to the load.
By turning the handle of the lifting magnet you change the magnetic
direction of the magnetic source in the rotor and therefore to
attract and release the load.
Permanent lifting magnets have some advantages as follows.
- Permanent lifting magnets use magnet materials as the magnetic
sources and don’t need any external power supply. So that
they can be used any place.
- Permanent lifting magnets are composed of magnet materials and steel parts
only, they are durable with little maintenance.
- Permanent lifting magnets can be simply operated by hand. The operation of permanent
lifting magnets are very easy.
- The costs of the permanent lifting magnets are lowest among all types of lifting
But, permanent lifting magnets have some disadvantages.
- The magnetic field from the poles of the permanent lifting magnets are shallow,
compared to electro lifting magnets. Consequently the lifting capacity of the permanent
lifting magnets decreases significantly as the
air gap between the magnet and the load
to be lifted increases. Any dust, scraps, paint, and rust contribute the air gap.
- There are two limitations of the load thickness. First is for the rated lifting
capacity, the actual lifting capacity will less than the rated capacity if the load
thickness is less than this limitation. The second limitation is for turning the handle.
You cannot turn the handle if the load thickness is less than this limitation.
- The larger the lifting capacity of permanent lifting magnets, the harder the turning
of the handle from OFF position to ON position. The maximum capacity of permanent lifting
magnets should be 2,000 kgs (4,400 lbs), over which it is hard to turn the handle from
OFF to ON. (A few manufacturers make permanent lifting magnets of lifting capacity over
2,000 kgs. However, these big lifting magnets are not easy to turn the handles.)
- Permanent lifting magnets are operated manually and cannot be controlled from
distance. They are not used in an atomization system.
In summary, if your workloads to be lifted are
- Flat, thick and relatively clean plates, or
- Regular rounds
(Details please read Instruction Manual)
You could select permanent lifting magnets to use. Otherwise, please consider electro lifting
magnets and electro-permanent lifting magnets.