Crane lifting magnet systems · electro, battery and permanent magnets, workload limit versus tested capacity and safety factor, flat versus round loads, temperature derating, duty cycle and power-failure backup
A crane lifting magnet system is a magnet hung from a crane hook or beam, with its power supply and controls, that holds steel loads by magnetic force instead of slings or hooks: electromagnets need current while lifting, battery magnets carry their own supply, and permanent or electro-permanent magnets are switched on and off. Ask three things first: what workload limit applies to your load's shape, thickness and temperature, which magnet type and duty cycle suit the work, and what keeps the load held if power fails.
Electromagnetic, battery-powered, permanent and electro-permanent lifting magnets and magnet systems for cranes, including scrap magnets, plate and bundle magnets, magnetic lifting beams and their power supplies and controllers. Magnetic separators, formwork (shuttering) magnets, magnetic chucks and cranes sold without magnets are outside this page except where compared.
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01
Walmag's catalogue shows how lifting magnets are rated. Its Neo permanent magnets list a tested lifting capacity, a workload limit for flat material and a lower workload limit for round material, for example a NEOL1000 tested at 3,200 kg with a 1,000 kg limit on flat and 500 kg on round loads, and meet a 3+ safety factor under EN 13155, with a tear-off test made with an air gap. Its standard Neo works to 80 °C and its Neo Hot version to 180 °C. Its battery magnets carry a 2:1 safety factor, for example BM2500 with 2,500 kg workload limit and 5,000 kg tested capacity. Its GP 250 plate magnet handles sheets from 3 mm and can take single plates from a stack from 4 mm. [1]
Tractel's guidance for its Magfor high-temperature electromagnet notes that magnetic attraction falls as steel heats toward its Curie point, that irregular or curved surfaces and heavy scale reduce contact area and lifting force, and applies derating by load temperature: 100% of rated load up to 100 °C, 90% at 200 °C, 75% at 300 °C, 60% at 400 °C and 50% at 500 °C. [2]
Editorial calculation: a magnet rated 10 t on cold steel would, under that derating, be limited to about 10 × 0.75 = 7.5 t on material at 300 °C and 5 t at 500 °C. Walmag's NEOL1000 figures, 3,200 kg tested against 1,000 kg working on flat steel, give a ratio of 3.2, above the 3:1 safety factor. Rating and temperatures are assumed examples; use the maker's table for your magnet.
Give the supplier the loads (plates, bundles, billets, slabs, coils, scrap, rounds), dimensions, thickness and surface condition, maximum temperature, heaviest lift, number of pieces per lift, crane capacity and hook height, duty (lifts per hour), power supply, required backup time on power failure, controls (tip-off, variable force) and the safety standard to apply.
02
Tractel contrasts the types: permanent magnets work without electricity but need mechanical switching; electromagnets allow remote on/off control and suit fast repetitive lifts but must stay powered while lifting and need overheating managed; electro-permanent magnets switch with a brief charge and need no continuous power. It defines duty cycle as how often and how long a magnet is energised, which matters in hot work where heat builds up. [2]
Walmag rates its battery magnets at a 50% duty cycle with about 8 hours of battery life at that cycle and offers remote control and tip-off and variable-force functions. For electromagnets, including scrap magnets, it supplies power units with a transformer or DC converter and dynamic demagnetisation, a load test, tip-off and graded magnetisation, and standard backup for 20 minutes after a power cut. [1]
Editorial note: ask the supplier for the duty-cycle rating at your lift rate, the backup duration and alarm on power loss, and how the magnet and load are prevented from swinging over people.
For scrap yards, Ohio Magnetics' LOADSTAR and SUPER LOADSTAR electromagnets show how scrap magnets are listed: diameters from 48 to 72 in (1,220 to 1,829 mm), cast cases except the fabricated 72 in size, continuous duty cycle ratings, a deep-field (LOADSTAR) or extra-deep-field (SUPER LOADSTAR) coil, chain suspension, a standard hard-face weld on SUPER LOADSTAR for abrasion, and 230 VDC as standard supply with other voltages on request. It gives a lifting capability range of 1,800 to 4,200 lb for LOADSTAR and 2,200 to 5,600 lb for SUPER LOADSTAR, and matches magnet options to the excavator's mechanical and hydraulic capacity. [4] Editorial calculation: those ranges are about 816 to 1,905 kg and 998 to 2,540 kg per lift; unlike the plate ratings above, they describe scrap pick-up, so ask the supplier for the figure for your scrap grade and for the carrier's lifting capacity with the magnet's own weight added.
03
Goudsmit Magnetics' knowledge-base note on lifting magnet safety states that, under EN 13155, the recommended workload should include a safety factor of 2 for electromagnets and vacuum lifters and 3 for permanent and electro-permanent systems. It notes that electro lifting magnets switch quickly without wear but risk dropping the load if power fails, which is why they are fitted with a back-up system. [3]
The note adds that heavy magnet-lifted loads can sway beyond what can be corrected by hand. Use these factors with the maker's flat- and round-material ratings and the power-failure options described above to choose the magnet size. [3] [1] [2]
Editorial calculation: to hold a 2,000 kg plate with a factor of 3, a permanent magnet needs a tested pull-off of at least 6,000 kg on that plate; an electromagnet with a factor of 2 needs at least 4,000 kg.
| Point from the Goudsmit note | Value or requirement |
|---|---|
| Safety factor, electromagnets and vacuum lifters (EN 13155) | 2 |
| Safety factor, permanent and electro-permanent magnets (EN 13155) | 3 |
| Electro magnets | Back-up system against power failure |
| Where people could be endangered by a falling load | Limit fall distance to 1.5 m, unless a retention device such as a chain catches the load |
| Before lifting | Risk analysis covering magnet, suspension and control system together |
State the heaviest, thinnest and hottest loads, whether people work under the lift path, and the standard you work to, and ask for the magnet's tested pull-off force, the safety factor applied, back-up power and any retention device.
04
Suppliers linked to this page list crane lifting magnets; each card links to the page reviewed.
Listings include electromagnetic and automatic lifting magnets, excavator lifting magnets, lifting magnets offered by crane and hoist makers, and electromagnetic overhead cranes with magnets for slabs and billets. Ask each for workload limits by load type and temperature, safety factor, duty cycle and backup.
05
This is a functional reference built from the sources cited; it is not one maker's specification.
| Part | Role | Fix in the order |
|---|---|---|
| Magnet body and poles | Hold the load. [1] [2] | Type, size, pole layout. |
| Coil (electromagnets) | Generates the field; heats in use. [2] | Insulation class and duty. |
| Power supply and controller | Magnetise, demagnetise, tip-off. [1] | Converter and functions. |
| Battery or backup | Holds load on power loss. [1] | Backup time. |
| Lifting eye or beam | Connects to the crane. [1] | Rating and attachment. |
| Remote control and display | Operation and status. [1] | Range and indicators. |
06
A lifting magnet quotation needs values for your loads and crane. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Rated Lifting Capacity (t) | Workload limit, by load shape. [1] | Limit for your load and temperature. |
| Magnet Diameter (mm) | Size for scrap or loads; one scrap series spans 48–72 in (1,220–1,829 mm). [4] | Dimensions. |
| Magnetic Flux Density (T) | Field strength. | Value or tear-off test result. |
| Power Consumption (kW) | Electromagnets. | Cold and hot power. |
| Supply Voltage (V AC) | Power unit input. [1] 230 VDC standard on one scrap magnet series. [4] | Voltage and DC output. |
| Duty Cycle (%) | Example: 50% for battery magnets. [1] [2] | Duty rating. |
| Operating Temperature (°C) | Examples: 80 °C, 180 °C; derating to 500 °C. [1] [2] | Load temperature limit. |
| Ingress Protection | Outdoor or scrap yard. | Rating. |
| Material Grade | Body and poles. | Materials. |
| Weight (kg) | Crane capacity check. | Weight. |
| Safety factor | Examples: 3:1 (EN 13155); 2:1. [1] | Factor and standard. |
| Safety factor | EN 13155: 2 for electromagnets, 3 for permanent and electro-permanent magnets (per Goudsmit). [3] | Factor applied to the rating. |
07
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Loads: [type; size; thickness; surface; weight] Temperature: [maximum] Crane: [capacity; hook height] Duty: [lifts per hour] Type: [electro; battery; permanent; electro-permanent] Power: [supply; backup time] Controls: [tip-off; variable force; remote] Standard: [safety factor; EN 13155 or other]
These companies list crane lifting magnets.
Lists electromagnetic and automatic lifting magnets, including magnets for excavators.
Product scope checked 2026-10-11
Lists crane lifting magnets with cranes and transfer carts.
Product scope checked 2026-10-11
Lists lifting magnets for cranes with overhead cranes.
Product scope checked 2026-10-11
Lists crane lifting magnets and electromagnetic overhead cranes for slabs and billets.
Product scope checked 2026-10-11
Lists lifting magnets with hoists, trolleys and clamps.
Product scope checked 2026-10-11
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Contact area is smaller; Walmag's permanent magnets list round-material limits at about half the flat-material limit. [1] [2]
Tractel's Magfor guidance gives 100% up to 100 °C, 75% at 300 °C and 50% at 500 °C. [2]
Walmag supplies electromagnet power units with standard backup for 20 minutes after a power cut. [1]
Goudsmit Magnetics cites EN 13155 as requiring a factor of 2 for electromagnets and vacuum lifters and 3 for permanent and electro-permanent magnets. [3]
Ohio Magnetics lists 1,800–4,200 lb for its 48–72 in LOADSTAR magnets and 2,200–5,600 lb for SUPER LOADSTAR, at 230 VDC with continuous duty ratings. [4]
Sources checked 2026-10-12. Walmag, Tractel, Goudsmit Magnetics and Ohio Magnetics are lifting magnet makers describing their own products; their ratings and derating figures are examples, not limits for other makes.
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