Many Australian companies have a strong focus on reducing hand and wrist injuries. They may be interested in an Active Shunting Magnet due to it’s more gentle actuation. Deep Field Magnets can be quite forceful when being turned on and off, particularly when it is operating too far from its maximum magnetic saturation thickness. For example, a 3-tonne Passive Shunting Lifting Magnet is not rated for use below 30mm and is a happier operation in the 50mm-80mm range.
The other reason Active Shunting Magnets are good at preventing hand injuries is to have no residual magnetism. This eliminates the requirement to remove swarf and grit from the bottom of the magnets between lifts thus reducing the risk of laceration type hand injuries.
Do you intend to lift material less than 10mm thick?
If so, be aware that many Passive Shunting Magnets are not rated for it. The two main reasons are that you have to apply so much force to the handle that the magnet can be damaged and once the magnet is actuated, so much of the flux is wasted below the sheet metal.
If you’re using the magnet to lift sheet or plate off a stack, you’re most likely better off with a Shallow Field to reduce the chance of picking up multiple pieces.
Preventing damage to Materials
Does the material have to be handled carefully to reduce the risk of scratching it? If so an Active Shunting Magnet with zero Residual Magnetism is the way to go. See our video on Residual Magnetism for more detail on this.
Handling billet or very thick steel 40-80 mm plus
A Passive Shunting Magnet is usually a good choice and really come into their own here. Just ensure that the magnet has a two-action control that prevents accidental discharge as per the Australian standard. We see many for sale in Australia that doesn’t.
We are not playing favourites here, we highly recommend our Passive Shunting Prolift range, they are robust and dependable. We also really like the Active Shunting Magswitch products for their technology and all the solutions they offer.
Contact MSA today for advice on selecting the right Lifting Magnet for your application.
Lifting magnets will achieve different hold forces depending on the thickness of the steel it is in contact with.
Some magnets are geared towards lifting thin material (Active shunting) and some thicker material (Passive Shunting).
Let’s look at how the two compare at the midrange thicknesses we commonly handle in Australia:
The active shunting Magnets are more likely to lift the number on the side of the magnet as they waste less flux due to the more efficient circuit. This reduces the risk of operator error.