Leading lifting magnet/electromagnet

The leading lifting magnet is not just a warehouse equipment. This is the intersection of physics, reliability and daily use. We have seen one incorrectly selected electromagnet stop an unloading line for 47 minutes. How overheating a coil in high humidity conditions reduces life by 30%. And how a simple error in calculating the lifting force leads to a load falling when lifting 80 mm thick steel plates. These are not hypothetical scenarios. These are real cases from our technical reports over the past five years.

Why “leading” is not a marketing category, but an engineering category

A lifting magnet becomes a leading one when it meets three strict criteria: stability of the holding force when the mains voltage fluctuates, protection against overheating without forced cooling and adaptation to the actual surface of the load - rusty, oily, rough. For example, at a voltage of 360 V instead of the nominal 380 V, many electromagnets lose up to 45% of their lifting force. The leading models of the LONGI corporation retain at least 92% even at 340 V - thanks to the optimized magnetic core design and improved thermal design of the winding. We tested this on a stand with a cyclic load: 1200 cycles of lifting and lowering scrap steel weighing 1.8 tons. The case temperature did not exceed +68 °C. Not a single refusal.

Electromagnet ≠ lifting magnet: where mistakes are most often made

Some customers ask for “any powerful electromagnet for a crane.” But this is like asking “any engine for a car” - without specifying the torque, transmission type and operating conditions. The lifting magnet is a specialized class. It must withstand shock loads when lowered, have hermetically sealed class H insulation (up to +180 °C), and provide an emergency shutdown system in the event of a power failure. A conventional industrial electromagnet does not meet such requirements. We encountered a situation where a client installed a universal electromagnet on an overhead crane. Three weeks later, an insulation breakdown occurred due to condensation in a workshop with a temperature of +5 °C and a humidity of 85%. LONJI's leading lifting magnet is IP66 rated and double insulated with vacuum impregnated epoxy resin. This protection works both in the freezing shop and in the foundry with Fe₃O₄ dust.

How to choose - without overpayments and compromises

The decision begins not with price, but with four parameters: weight and type of cargo, metal thickness, cycle frequency, environmental conditions. For sheet metal with a thickness of 6–12 mm, a model with a nominal force of 3.2 tons is suitable - but only if the surface is clean and flat. When working with rusty scrap or bent parts, a reserve force of at least 1.8 x the design value is required. We recommend carrying out a test load: take a sample of the load, measure its thickness and roughness, hang it on a magnet and record the holding time when the voltage drops to 340 V. If the holding is stable for more than 60 seconds, the choice is correct. There are 27 modifications of lifting magnets in the LONGI catalogue: from compact 1.2 ton systems for hand trolleys to heavy-duty 25 ton systems for port cranes. All of them are certified according to GOST R IEC 60204-1 and have passport data on the actual holding force at different temperatures and humidity.

Reliability is not a characteristic, but a process

The leading lifting magnet does not appear in the workshop by itself. It goes through 14 stages of control: from checking the cleanliness of the magnetic core steel to testing for vibration resistance at a frequency of 55 Hz. Each device undergoes 100% load testing. The production site in Fushun has 140,000 m², more than 1,200 employees, 60% of them are engineers with higher education. 4,000 units of equipment are produced annually. These are not numbers from a presentation - this is a guarantee that each electromagnet sent to the customer has already been tested under conditions close to its future operation. Websiteljmagnet.rucontains not only a catalog, but also methodological recommendations for installation, connection diagrams, tables of corrections for temperature and humidity. Because the presenter is the one who helps to work, and not just sells the device.