Magnet maintenance for productivity and longer life

Lifting magnets are often revenue generators for scrap metal yards and steel production facilities. But you could be getting more for your money from your magnet system.


Magnets are poorly understood. They can be incredibly reliable and potentially last for many years of service. Instead, we find that working with magnets chronically underperform and are often a costly maintenance item.


What causes magnets to fail?


Heat is the number one reason for premature magnet failure. Moisture, electrical system faults and simple abuse can also compromise magnet performance, but heat is by far the most important factor.


The first place to look for heat-related magnet problems is in the magnet’s duty cycle. The length of time that the magnet is powered up during the lifting cycle is critical. Think of it like this – the average toaster produces 800 watts of heat during its work cycle. A typical 66” magnet produces nearly 20,000 watts. That is a lot of heat and unlike toasters, magnet casings are not vented.


We recommend that the operator stays well within the recommended duty cycle rating. A common problems is that inexperienced operators power up the magnet too early in the lift cycle, allow too much on time for the unit to heat up. A hot magnet loses up to 25% of its lifting capacity.


External sources of heat can be another factor in magnet performance, including the temperature of ambient air and the temperature of the material being lifted. This is important in steel mills and foundries where air temperatures and material temperatures are extreme. Magnets in these applications must be designed for hot surface work.


Incorrect use of a magnet is costly. Abuse and heat not only wear out the magnet faster; they can undercut the entire material handling capacity for a long time before the magnet finally fails.


Magnet performance – a checklist


  1. Operate within specified duty cycle ratings
  2. Turn off magnets when not in use
  3. Use magnets for their intended purpose.
  4. Reduce air gaps in loose material before lifting.
  5. Avoid lifting hot materials, if possible.
  6. Do not exceed recommended voltages.
  7. Inspect for shorted or grounded coils.
  8. Rotate hot magnets on a buddy system.
  9. Repair cracked casings and damaged connections.
  10. Correct or replace faulty controller components.
  11. Do not use the magnet as drop ball or ram.
  12. Ensure magnet casings are water-tight
  13. Store magnets off the ground where possible.

If you have a industrial magnet that needs repair – why not look at our magnet repair section and get in touch to find out how we can help you.