QC Electromagnetic Overhead Crane with Lifting Magnets

Yuantai QC-type overhead cranes are equipped with a backup power supply and safety interlock devices, enabling them to securely hold the load even during a power outage, thereby effectively preventing accidents. By directly lifting steel materials, these cranes eliminate the need for hooks and tie-downs, helping to improve the efficiency of steel handling.

Key Features & Advantages

1. Specialized for Ferrous Materials

The QC crane is built specifically for magnetic material handling. Its lifting magnet is optimized to pick up steel plates, billets, profiles, ingots, pig iron and scrap steel. Unlike a conventional hook crane, you don't need chains, slings or clamps; you simply lower the powered magnet, it seals onto the metal surface, and you lift – streamlining every cycle. This eliminates complex rigging and reduces manual labor.

2. High Efficiency & Throughput

With instant attach/release, magnets cut pick-and-place time dramatically. Yuantai's QC crane can "fasten in a matter of seconds and remain firmly in place as the crane travels". You simply lower the magnet, it grabs, and you lift – no threading slings or guiding hooks. In practice, material movers find they can handle many more tons per hour compared to manual methods or hook cranes.

3. Powerful Holding Force

The integrated electromagnet delivers a firm, even grip across the contact surface, distributing force over a wide area. This multi-point magnetic hold resists shifting and slippage during travel. In large-sheet or bundle lifts, magnets avoid pressure points that slings or clamps can cause, reducing damage to the material. When evaluating magnets, always check the rated holding force for your load thickness and surface finish: Yuantai's magnets are rated for clean, flat steel contact, and we advise allowing margin for any rust or gaps.

4. Flexible Cabin & Control

You can choose cabin layout and controls to fit your workshop. The operator cab can be installed on either the left or right side of the bridge, and entry can be from the end, side, or even top. Both ground-level and in-cabin control are available; many customers pair the QC crane with both pendant and wireless remote for convenience. This adaptability helps the QC crane fit into various plant layouts.

5. Customizable Magnet Configuration

Yuantai offers different magnet sizes and shapes to match your material. You can specify circular or rectangular electromagnets (or even permanent or electro-permanent magnets) based on the geometry of your loads. For example, circular magnets with deep fields are ideal for coils, ingots, or scrap piles (as they concentrate pull in one spot), while flat rectangular magnets suit slabs and plate stacks (spreading force over a broad face). You can also use spreader beams with multiple magnets for extra-wide loads. Our engineers will recommend a magnet layout that handles your material weight, shape, surface finish, and stacking method most effectively.

6. Durable Heavy-Duty Design.

The QC crane's bridge is a welded box-girder structure made from high-strength carbon steel (Q235B/Q345B, equivalent to Fe37/Fe52). It is optimized for heavy loads and long spans. All welding is automatic and certified (non-destructive testing of welds). The hoisting trolley uses a robust winch drive and helical gear reducer; the drive motors have efficient F-class insulation for safety.

7. International Safety & Quality

We equip the QC crane with overload limiters, height limiters, audible/visual alarms, and anti-collision buffers. The control system includes emergency stop functions and can integrate with your plant's PLC. All electrical components are industrial-grade. When the magnet is energized, emergency battery or UPS backup can be added so the load stays held during power outages.

Magnet Types: Choosing the Right Lifter

Yuantai offers three main magnet options for the QC overhead crane: electromagnets, permanent magnets, and electro-permanent (hybrid) magnets. Each has trade-offs:

• Electromagnets (powered coils) deliver very high lifting force and on/off control. As soon as current flows, the magnet strongly attracts steel; turning off the current releases it. You can adjust the pull by controlling coil current or turns, giving fine control for "multi-lift" tasks. However, electromagnets require constant power to hold a load; a power cut will drop magnetism unless backup is provided. Expect some electrical maintenance (coils and insulation) and plan energy needs for continuous operation.

• Permanent Lifting Magnets use magnetic alloys (typically rare-earth materials) to hold loads without any power. Once you engage the permanent magnet, it keeps the steel attached even if electricity is lost – an inherent fail-safe. This makes them energy-efficient and safe for long holds or sites with unreliable power. The drawback is they have fixed pull strength (usually lower than a comparably sized electromagnet) and releasing the load requires a special action: either an integrated mechanical lever or a brief pulse of current to reverse polarity. Permanent magnets need virtually no maintenance (no coils to burn out), but be sure the material type is suitable – for example, newer rare-earth versions give much stronger pull but at higher cost.

• Electro-Permanent (EPM) Magnets combine the two approaches. An EPM magnet contains both permanent and electromagnetic materials. A brief electric pulse flips its field between "on" and "off" states. Once on, it holds the load with permanent magnetism and draws no continuous power; to release it, you apply a similar pulse to reset it. Thus EPMs offer on/off control like an electromagnet but only need power during switching, combining safety (holds load in a blackout) with lower running cost. The trade-off is added control complexity and typically higher initial price.

In practical applications, for safety reasons, we generally recommend the latter two types of electromagnet lifting devices. We offer both round and rectangular electromagnets.

Magnet Shape and Configuration

Your material's shape and surface condition dictate magnet shape. Common configurations include:

• Circular (Disk) Magnets: These have a round footprint with vertically oriented poles. They concentrate force at the center, ideal for picking coils, ingots, scrap piles or bundles where you lift from the top. Heavy-duty circular magnets include deep-field coils and thermal insulation to run at high duty cycles and even at elevated temperatures (often up to 600–650°C). Choose a diameter and pull rating matching your load. If lifting steel wheels, coils, or bundled rods, a large circular magnet may work best.

• Rectangular (Flat) Magnets: These have a long, flat pole face. They spread the magnetic field across wide, flat loads – such as plates, sheets or slabs. Flat magnets often use tailored pole shoes to improve contact on imperfect surfaces (slightly uneven or rusty steel). For example, a 1.2×2.0 m flat magnet can lift several tons of steel plate if properly contacted. Flat magnets are built for heavy use, with robust coils and cooling; some are rated for hot work at several hundred °C. Key considerations: match the pole face length to the plate width and ensure strong contact. Plan to prepare surfaces (clean off heavy rust/dust) for best lift.

• Spreader-Beam Mounts: For extremely long or irregular loads, such as bundles of pipes, rails, or rebar, multiple lifting magnets can be arranged along a dedicated spreader beam to distribute the lifting force across several points. This configuration can help improve load balance when handling materials that are too long or difficult to lift securely with a single magnet. The number, spacing, and type of magnets should be selected according to the material's dimensions, weight, and lifting requirements. If you would like to learn more about overhead cranes used to lift extra-long steel beams, please check electromagnetic overhead cranes with magnet beam.

Technical Specifications

Yuantai's QC crane comes in capacities from 5 t up to 50 t (magnet included), spans from 10.5 to 31.5 m, and lifts up to ~28 m. Typical ratings are A6 duty. Below is a summary table of key specs (customizable to order):

Note: The listed lifting capacity includes the magnet's own weight. For example, if the magnet weighs 2 t, the capacity in our catalog has been rated factoring that in. When calculating your actual load, always subtract the magnet weight from the crane's gross capacity. Also, the crane's dead weight (bridge structure) is given separately and does not include the magnet weight.

Material Considerations & Magnet Performance

When using an electromagnetic crane, material properties directly affect performance. Here are factors to keep in mind:

1. Steel Type & Thickness

The magnet's rated pull is based on contact with clean steel of a certain thickness. Thin plates or bundles of loosely stacked sheets will reduce the effective lift. For thin loads, a stronger magnet or multi-magnet spreader may be needed.

2. Surface Condition

Dirt, paint, rust or mill scale can create air gaps that weaken attraction. Magnets need full contact with ferrous metal. Always ensure the surface is reasonably clean and flat – even small debris on the steel surface can significantly cut holding force. In critical lifts, consider pre-cleaning or use of magnets with tapered pole shoes to compensate for unevenness.

3. Operating Temperature

High heat can demagnetize certain materials. Standard electromagnets and permanent magnets have maximum operating temps. For high-temperature loads (red-hot ingots, forged billets, etc.), we offer specially insulated or water-cooled magnets. Yuantai experience shows typical cast-steel magnets can handle up to ~200°C continuous; for hotter loads (500–600°C+), we supply high-temperature magnets rated accordingly. In any case, advise your rep of expected ambient and load temperatures so we can specify the proper coil insulation and cooling.

4. Duty Cycle & Usage

Lifting magnets heat up under power. Industrial magnets usually run at a duty cycle (e.g. 60–75% of time on) to prevent overheating. For continuous 24/7 use (scrap yards, for example), we use magnets designed for high duty and may add forced cooling (fans or liquid cooling). Always monitor coil temperature and limit duty as per the magnet's spec sheet. Yuantai's QC cranes are rated for heavy use (A6), meaning short loads with frequent cycles, but we can upgrade magnets or controls for lighter duty or special needs.

5. Power Supply & Backup

The electromagnet needs a stable power source. Fluctuating voltage or supply interruptions can trip the magnet or drop the load. For critical lifts, include a UPS or battery backup to hold the field during outages. Yuantai can include a power-fail alarm and emergency battery pack so that if main power cuts, the magnet remains energized long enough for safe lowering of the load.

6. Coil and Current

Note that magnets draw significant current. Your facility's electrical infrastructure must accommodate the magnet current inrush. Control systems often include smoothing inductors or soft-start to prevent line dips. We will size cables and fusing to handle the magnet's requirements. Many Yuantai customers add an external chokes or DC bus to stabilize the current.

Safety & Usage Guidelines

Yuantai emphasizes safe magnet handling. When operating your QC crane:

1. Lock the Hook Swing

Always pin or bolt the trolley hook's rotating pulley to prevent free-swing. A swinging load can cause accidents. (We recommend fixing the hook rotation with a safety screw as soon as the crane is installed.)

2. Account for Magnet Weight

Remember that the crane's rated capacity includes the magnet's self-weight. Do not exceed the rated load minus the magnet weight.

3. Avoid Non-Ferrous Debris

Never allow wood, rock, or thick rust between the magnet and load. Even thin gaps or coatings significantly reduce lifting force. Before lifting, clear the steel surface of loose scale, metal chips or other non-metallic waste.

4. Hold Time & Drop Risk

Use built-in power-off retention if available. Many Yuantai magnets include a small backup battery or capacitor that keeps the field energized if power fails. Nonetheless, always treat an energized magnet as a controlled clamp: if power is lost and there is no backup, the load will drop. Keep personnel out of the drop zone, and allow only remote triggering of the magnet on/off during lifts.

5. Regular Inspection

Per ISO 9927, cranes must be routinely inspected for safety. For magnets, inspect the pole plates for wear, check coil insulation resistance monthly, and test the emergency battery. Verify all electrical connections are tight and cables have no breaks. Check the load limiter and height limiter functions periodically.

6. Operational Training

Only qualified operators should use the crane. Provide training on magnet operation, including the fact that magnetic lifts can hold steel across their entire face. Emphasize that no one should ever walk under a suspended load, even if magnetized. Use warning lights or horns to signal crane motion when lifting heavy stacks.

By following these guidelines, you can exploit the crane's advantages while maintaining a safe work environment.

Comparison: QC Crane vs. Magnet-Beam Crane

Yuantai also makes Magnet-Beam Overhead Cranes, but the QC type with a single hanging electromagnet has distinct benefits for some uses:

Applications and Industries

QC Electromagnetic overhead cranes are found in:

Steel Mills and Fabrication Plants

Lift steel slabs, plate bundles, beams and coils. Magnetic cranes can also feed steel plates into presses or mills.

Metal Warehouses

Handle stored steel sheets and metal profiles quickly and safely, with less manual rigging.

Scrap Yards and Recycling

QC electromagnetic cranes collect and sort ferrous scrap and charge furnaces, reducing manual handling.

Foundries and Auto Plants

Move ferrous castings, engine blocks and stamped metal parts to reduce manual handling and improve material flow.

Technical Data and Drawings

We include detailed technical drawings and specification sheets with every quote. For brevity, here's a sample technical summary for a 20/5t and 32/5t QC overhead crane.

Technical Specifications

(Example data – actual values vary by configuration. Magnet weight ~1000–2000 kg depends on size.)

For exact planning, we'll provide the wheel loads, rail types, and detailed beam dimensions. Your engineers can use these figures to design runway beams and floor piers.

FAQs

Q1: How do I decide between circular and rectangular magnet?
A: Circular magnets concentrate force and are best for round loads like ingots or scrap piles. Rectangular (flat) magnets cover large flat surfaces like steel plates or sheet bundles. Consider the typical load geometry: choose circular if you often lift stacks of billets or coils, and flat magnets if handling sheets or plates. We can also supply spreader beams with multiple magnets for long loads.

Q2: What happens if power is lost during a lift?
A: Yuantai's lifting magnets can be ordered with power-off safety. By default, a DC electromagnet will drop the load if power cuts. We highly recommend adding a backup battery or capacitor module. This energy storage keeps the magnet energized for several minutes during a blackout. Additionally, all our control systems have alarms and interlocks, and we train operators to clear the crane path on power failure.

Q3: How do I maintain the magnet?
A: Perform periodic checks: inspect the magnet's pole faces for wear, measure coil insulation resistance, and check that the electrical cabinet is clean. Test the emergency battery and control circuits regularly. Keep the magnet cool and don't exceed duty cycle. If the magnet overheats, stop operation and let it cool – prolonged overheating can reduce magnet performance over time. Yuantai's engineers will provide a maintenance schedule based on your usage.

Q4: Can this crane handle non-iron materials?
A: No. Magnet cranes only lift ferrous (steel) materials. Non-magnetic loads will simply not pick up. For mixed shipments, you will need separate handling (hooks for non-ferrous parts). Also note that a thin layer of rust or mill scale is usually fine, but wood, concrete, dirt or plastic between the magnet and steel will block lift.

Q5: What certifications and standards does the QC crane meet?
A: The QC crane can be supplied with CE marking and ISO9001 documentation. We design to CMAA duty classifications and ISO rules for cranes. For example, our duty A6 corresponds to CMAA Class II/III. We also follow ISO 4301 classification for service conditions and ISO 9927 inspection guidelines. If you have specific requirements (like crane inspector certification or country-specific regs), let us know.

Q6: How customizable is the crane?
A: Very. In addition to magnet type, we can adjust span, height, control mode, insulation class, etc. You can select the hoist gear ratio for faster speeds, choose special paint, add sway control, upgrade to cold-area components, and more. Just tell us your requirements (lifting data, environment, any special approvals) and we'll configure the QC crane accordingly.

Q7: Why not a gantry crane?
A: A gantry or portal crane (leg-supported) is a different crane type and may be preferred for outdoor yards or heavy loads requiring open space. The QC bridge crane is ideal if you have a building with runways or want overhead space usage. We also make double-girder gantries if needed – just ask.