- Ben Nordman
Reading A Lift Magnet Tag: What does a rated load capacity mean?
Updated: Mar 2
One of the most important readings from a battery-operated lift magnet tag is the rated load capacity. While the load capacity rating might seem pretty self-explanatory, let’s get into how that is calculated and what it means for the operator.
With different lift magnets can come slightly different terminology on the tag. On our new lift magnets, the tag reads "rated load capacity", while older tags could read "rating capacity" or other similar verbiage. It's important to know which information is which to safely perform a lift.
The American Society for Mechanical Engineers (ASME) sets the standard for battery-operated lift magnet safety from a manufacturer’s standpoint. The standards are revised every few years and cover every lift magnet type one could think of and includes requirements for design, including how a lift magnet load capacity rating is calculated.
We will be covering battery-operated lift magnets in this article, as it is our most popular lift magnet that Obsidian Manufacturing Industries, Inc. produces. The standard that ASME sets differs based on type of lift magnet that is in question. Please reference the standard for other types of lift magnets and if you have any questions.
When a battery-operated lift magnet is produced, the desired lifting for the model is tested with a load test on a test stand in addition to an operational test of all components. A load test, or breakaway test, is a process that applies force against the pull of the battery-operated lift magnet. Once the magnet breaks away from the stand, the stand gives a reading on the amount of pounds of force that is applied at that breakaway point, meaning when the lift magnet will fail when performing a real lift.
This breakaway point is the absolute maximum amount of pounds that can be applied before the battery-operated lift magnet fails the lift and loses the load. As the standard for battery-operated lift magnets stated by the ASME, the rating capacity is calculated as less than 50% of the breakaway point.
As an example, a battery-operated lift magnet is tested and gets a breakaway point of 20,000 lbs. The load rating capacity that is put on the tag for that individual battery-operated lift magnet must read 10,000 lbs. or less according to the ASME. This allows an adequate amount of difference between the breakaway point and the rating capacity to maintain a safe lift and limit lifting injuries. Other factors play into a safe lift other than a breakaway point or only doing a load test.
It is recommended that a load test is done annually by a qualified person in order to maintain a safe lift, always. We DO NOT recommend conducting any testing on your own. We test and certify the lifting capacity rating in our shop for lift magnets. We provide documentation of the breakaway test for your records as requested.
NOTE: A load, or breakaway, test is not a full inspection of a lift magnet, it only is used to calculate the load rating.
Obsidian Manufacturing Industries, Inc. is a Rockford, Ill. manufacturing company and is the OEM for Magna-Lock USA workholding, MagnaLift & Power-Grip lift magnets, and Arter Precision Grinding Machines as well providing surface grinding services. They are located at 5015 28th Ave. in Rockford, Ill. with a phone number of 815-962-8700. Check out more at obsidianmfg.com/brands.