Residual magnetism in
lifting magnets occurs when a magnet fails to turn completely off.
This magnetic flux
results from a circuit being created between the rare earth magnets inside and
the steel body of the magnet. The level of residual magnetism depends on the
shunting technology and the overall design of the magnet.
So how does residual
magnetism affect your lifting magnets? The following three examples show the
effects of residual magnetism found in lifting magnets and prove why magnets
with no residual magnetism are the safest option.
Extreme residual magnetism
residual magnetism will cause the magnet to collect ferrous particles and
debris even after it has been turned off
will likely cause an air gap on subsequent lifts and may permanently damage
the magnet. This can significantly de-rate the magnet’s SWL (Safe Working
Load) and the magnet could fail a pull test
risk of hand injuries if the operator tries to manually separate the
magnet from the load
material being handled will also be damaged by any debris stuck to the
Low residual magnetism
good quality passive shunting magnet has a small amount of residual
magnetism, although not enough to risk hand injuries
magnet will still require regular inspection for debris; however, you can
expect it to collect much less debris than the first magnet.
No residual magnetism
magnet uses active shunting technology, which allows it to be turned off
is the safest type of magnet and is also unlikely to collect any ferrous
debris after being turned off
the event of damage to the working surface, replacement pole shoes can be
fitted safely and easily using basic tools in your workshop.
MSA Pro-Lift and
Magswitch lifting magnets are designed to have a clean break of magnetic flux
at the OFF position.
MSA Magnetics ensures
the highest industry safety standard as well as ease of use for their industrial