Overband magnet: which magnetic separator should you choose?

Permanent, mobile or electromagnetic overband magnet: compare the 3 types of Lenoir-Mec overbands. Technical data and selection criteria for industrial users.

Fixed permanent magnet, mobile permanent magnet or electromagnetic?
The choice of an overband magnet determines your sorting efficiency, your energy costs and your maintenance. Each technology meets specific constraints: stable or variable flow, fixed or mobile installation, need for control or search for autonomy. Lenoir-Mec gives you a clear overview of the three main options on the market to help you identify the one that truly matches your production configuration.

How to use this specifications table: OVAP vs OVAPEM vs Electromagnetic

These three technologies fulfil the same task: extracting ferromagnetic contaminants from your product. They differ in how they achieve it and in the constraints imposed by your installation.

The selection process starts with your operating constraints. The width of your conveyor determines the compatible models. The weight of the magnetic separator is just as decisive: suspending 13 tonnes (OV maximum) is a completely different matter from 1.4 tonnes (OVAP). Your steel structure must withstand this load; this is a technical requirement.

Once these constraints have been validated, examine your energy and operational context. Permanent magnets (OVAP) generate their magnetic field without consuming electricity, 24/7, without variation. The electromagnet (OV), on the other hand, requires a continuous power supply, but in return delivers greater separation power: you choose between a permanent magnet and an electromagnet.

The table summarises these trade-offs: compatible dimensions? Supportable weight? Power available or autonomy required? Each “no” or “yes” answer eliminates or confirms, until you choose the technology that suits your needs.

Permanent Magnet Overband (OVAP): The Benchmark for Fixed Conveyors

The OVAP is the magnetic separator for fixed lines: aggregate quarries, mining and quarrying, inert waste recycling, food processing industries, sawmills.

Key features: The Permanent magnet overband has low power consumption (belt drive motor). Thanks to its permanent magnets (ferrite or neodymium), it operates without a power supply for magnetisation, 24/7, 365 days a year. Its integrated self-cleaning system discharges the captured ferromagnetic items without human intervention. With a conveyor speed between 0.5 and 3 m/s, it is suitable for most production lines. Maintenance is virtually non-existent.

Flexible mounting (crosswise or in-line over the discharge point) allows easy integration into a variety of configurations, even on existing lines, while ensuring continuous, steady extraction of ferrous metals.

Operation: The permanent magnets generate a constant magnetic field that attracts ferromagnetic contaminants passing beneath the separator. These contaminants are held against the integrated conveyor belt, then discharged into a discharge zone, away from the main flow.

Case study: Aggregate quarry in Auvergne-Rhône-Alpes

Context: A quarry producing aggregates was experiencing recurring ferrous contamination problems (pieces of reinforcement, bolts) causing breakdowns on the secondary crushers, with significant costs in interventions and repairs.

Solution: Installation of an OVAP above the crusher feed line, matched to the product characteristics.

The production manager reports: “We installed the OVAP in June, and since then we forget it’s there. It runs, it does its job, full stop. No more emergency shutdowns, no more stress, no more breakdowns. A significant gain in profitability.”

Permanent magnet overband for mobile shredding equipment

The OVAPEM is the separator designed for mobile shredding equipment: mining and quarrying with mobile installations (tracked crushers), demolition sites, and mobile forestry operations.

Key features: Designed to be installed on mobile equipment. The OVAPEM has all the advantages of permanent magnets (low maintenance). Its robust, lightweight design incorporates powerful permanent magnets. The self-cleaning system operates continuously and ensures consistent performance.

Operation: Technically, the OVAPEM works on the same principle as the OVAP: permanent magnets and continuous discharge of contaminants. The OVAPEM easily adapts to the different sizes of your mobile equipment.

Case study: Mining and quarrying in the Grand Est region

Context: A company operates in a quarry with a mobile shredder to recover minerals. Ferromagnetic items (scrap iron, nails, reinforcing bars) degraded the quality of the recycled minerals and made them harder to resell.

Solution: Integration of an OVAPEM on the mobile shredder to remove the contaminants.

The technical manager explains: “ The OVAPEM has transformed our process: the minerals are cleaner and we finally obtain a marketable product.”

Electromagnetic Overband: The benchmark for separation in demanding environments

The electromagnetic overband is designed for demanding industrial installations: SRF (Solid Recovered Fuel) sorting plants, mining and quarrying, cement plants, recycling and recovery of industrial waste and municipal solid waste, the wood industry and food processing.

Key features: The assembly is based on a rectangular electromagnet suspended by four robust double-drilled lugs, supported by two U-section profiles that hold the drums mounted on bearings. It is driven by a hollow-shaft geared motor. It is completed by an endless discharge belt fitted with stainless steel fasteners.

Operation: Electromagnetic overbands generate a deep magnetic field, ideal for processing flows with a thick burden of material. Installed above a conveyor or at its discharge end, the unit effectively attracts and extracts ferrous contaminants. These are discharged automatically by the integrated conveyor belt. To further optimise separation, it can be combined with a metal detector. The equipment can also be de-energised when necessary for maintenance and cleaning operations.

Case study: SRF sorting plant in Île-de-France

Context: In an SRF sorting plant in Île-de-France, processing mixed waste required a solution capable of handling a higher product density.

Solution: To meet this requirement, an electromagnetic overband was installed in a crosswise position, combined with a metal detector to complete the sorting efficiency. This configuration made it possible to remove ferrous materials automatically and optimise the process.

The technical director emphasises: “The overband has considerably improved the efficiency of our line. We have gained in safety and in production performance. And with the Lenoir-Mec annual periodic inspection contract (after-sales service), we have gained peace of mind.”

In summary

**Permanent magnet

overband:**

Autonomous 24/7 separator with no power consumption for magnetisation, reliable with minimal maintenance.

Permanent magnet overband

for mobile equipment:

Compact and robust separator, designed for mobile equipment, ensuring continuous separation.

Electromagnetic

Overband:

Recommended for applications requiring a deep magnetic field for thick material flows.

FAQ: Overband magnet

What is the difference between permanent and electromagnetic?

The permanent overband uses magnets that generate a constant force without electricity (0 kW for magnetisation). The electromagnetic version requires 2-15 kW continuously to power the coils. In short: if your product is stable and of low density: permanent. If you want more power: electromagnetic.

Can these two technologies be used in the same installation?

OVAP or OVAPEM: which one to choose?

Permanent Magnet Overband (OVAP): Fixed installations

Permanent magnet overband for mobile shredding equipment : Mobile equipment only

• Lightweight design 120-450 kg (−30 to −40%)

• Stainless steel frame and components

• Resistant to vibration and 30° inclination

Identical magnetic performance; only the mechanical design differs. If your equipment moves, the OVAPEM is mandatory to meet weight constraints.

Can we install an overband on an existing conveyor?

Yes, integration on an existing site is common.

Points to check:

1. Structural strength: must support 150-1400 kg depending on the model
2. Available space: height + ferrous discharge chute
3. Power supply: 400V three-phase panel for the geared motor

The double-drilled mounting lugs on Lenoir-Mec overbands make it easy to adapt to different configurations.

What happens in the event of a power failure?

This is where the major advantage of the electro-permanent magnet lies: it automatically retains the load thanks to its passive safety. With a conventional electromagnet, the load can be released instantly if no backup safety system is provided.

Which metals are captured?

Ferromagnetic metals only:

• Iron, steel, cast iron, ferrous alloys

Does NOT capture:

• Aluminium, copper, brass, bronze

• Austenitic stainless steel: these metals require other technologies (eddy current separators)

Conclusion: Protect Your Installations Today

Choosing an overband is not limited to technical criteria: it must precisely match your on-site constraints and your performance objectives.

• For an autonomous, cost-effective solution, the OVAP stands out for its very low energy consumption. Equipped with permanent magnets (ferrite or neodymium), it operates continuously all year round, while its self-cleaning system discharges ferrous materials without human intervention, with maintenance kept to a minimum.
• If your operations require mobility, the OVAPEM is designed for seamless integration on mobile equipment, while retaining the advantages of permanent magnets.
• For greater power and control requirements, the OV provides a deep magnetic field, ideal for thick material flows, with the option of being de-energised for maintenance or cleaning.

At Lenoir-Mec, we guide you towards the most suitable solution through a fully customised approach:
site analysis, sizing, commissioning, responsive follow-up and regular inspections.

Would you like support in making your choice? Our experts will review your configuration free of charge and direct you to the most relevant equipment.

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