20/5 Ton Electromagnetic Overhead Crane – 34m Span 20m Lift

Cabin control gives the operator a clear view and a comfortable working position, especially with the industrial air conditioner in the cabin. Remote control lets the operator step away from the cabin for certain tasks — for example, to check the load, guide the magnet, or handle a tricky lift from a different angle. Having both modes gives flexibility in a steel ingot handling environment where conditions can change from lift to lift.

Full VFD (variable frequency drive) on the main hoist, auxiliary hoist, trolley travel, and long travel gives smooth acceleration and deceleration, precise load positioning, and lower mechanical wear. For steel ingot handling, this matters because the load is heavy, hot, and often needs to be placed into a mold or furnace with care. VFD also reduces the risk of load swing and makes the crane easier to control at slow speeds. The speeds in this drawing — main hoist ≥0.3 m/s, auxiliary hoist ≥0.45 m/s, trolley ≥0.7 m/s, long travel ≥1.5 m/s — are all achieved with VFD control.

IP54 means the electrical equipment is protected against dust ingress (5) and water splashes from any direction (4). In a steel ingot handling area, there is dust, scale, and sometimes water or coolant spray. IP54 keeps the motors, control panels, and VFD cabinets reliable in these conditions. Higher ratings like IP55 or IP65 are available for outdoor or washdown environments, but IP54 is the typical indoor rating for this type of crane.

QC = double girder electromagnetic overhead crane. "20/5t" = 20 t main hook, 5 t auxiliary hook. "34m" = 34 m span. "20m" = 20 m lifting height (main hook). "A7" = ISO A7 duty class (M7). A7 is a heavy-duty class for continuous work in demanding environments such as steel mills and foundries.

3-phase, 380 V, 50 Hz. This covers the 75 kW main hoist motor, the 30 kW auxiliary hoist motor, the trolley travel motor, the long travel motors, the VFD drives, the cabin control system, the remote control system, and the industrial AC. The high temperature electromagnet and its control system also operate on this power supply, usually through a separate magnet controller panel. The electrical quotation for the electromagnet system is handled separately.

Rail top elevation is the height of the top surface of the crane runway rail above the workshop floor. In this project, the rail top elevation is 16.4 m. This dimension is used to check that the crane, the cabin, and the load have enough clearance above the floor and below the roof structure. It also determines the hook approach and the available lifting height. The 20 m main hook lifting height is measured from the rail top or from the floor depending on the project convention, so the 16.4 m rail top elevation and the 20 m lifting height must be checked together.

Key safety features for high temperature electromagnetic overhead cranes include: battery backup or capacitor buffer to maintain holding force for at least 30 minutes after power failure; heat shielding between the magnet and the load to protect the coil; swivel-type mechanical suspension to prevent cable twist; armored flexible cable rated for high temperature and crane trailing applications; and residual magnetism release to ensure clean material drop. For steel ingot handling at up to 650°C, the magnet coil insulation class and the suspension chain material must be rated for the continuous heat load. This crane is specified with these features.