WL2520 Custom Holding Electromagnet solutions

Holding Electromagnet Advantages:

Remote control

Instant Engagement/Release: Using a simple on-off switch or PLC control, one can activate/desactivate magnets remotely, allowing automation.

Permanent On-Demand Hold: Once activated, the holding can continue indefinitely.

Compact Size and High Capacity: Significant holding force can be provided by a compact magnet (not larger than a coffee cup).

Mechanical wear Absence: Moving parts are absent, except for the electrical contacts.

Adjustable Force: Depending on voltage input one can easily pick up the object or release it in due time.

Minimal maintenance: Regular cleaning of the pole face and electric connections is enough.

Fail-to-Release: Once the current is switched off, the load is released. Can be an asset or drawback, depending on the process.

Disadvantages of Holding Electromagnet

Constant electricity supply requirement: Lack of power leads to dropping loads—potentially dangerous in overhead lifting operations. Solution: permanent electromagnets for fail-safe hold.

Heating Problems: Long periods of high-capacity operation may require cooling or limiting the duty cycle.

Residual Magnetism: After switching off the current, ferromagnetic objects may stick together, requiring additional efforts to remove.

Dependence on air gap: Force dramatically reduces with air gap (inversely proportional to its squared length).

Ferrous loads only: Aluminum, copper, wood or plastics cannot be picked up.

Inrush Current (AC variants): May lead to a breaker tripping.

Weight/Energy ratio: High forces require substantial magnet weights and thick cables.

Holding Electromagnet Troubleshooting Guide

Issues with holding electromagnets can be divided into three major types: either electrical, thermal, or mechanical. This article provides instructions on how to troubleshoot the problem in detail:

1. No magnetic force (has charge, but no magnetic attraction force)

– Make sure that voltage applied to the coil is within 10% of the nominal value.

– Carefully inspect all cables and terminals. The ends of cables may be rusted, loose, or damaged.

– Measure resistance of the winding using a multimeter. An open circuit implies a broken wire, while the coil with extremely low resistance (short) requires a replacement since insulation is destroyed.

– Check polarity: for DC electromagnets with a rectification circuit, a reverse polarity will not generate any magnetic field.

Weaker magnetic force than expected

– Clean both pole faces from any dirt: paint, rust, oil or other contaminants. They may form an air gap, reducing magnetic force by 80%.

– The workpiece should be thick enough. As a rule of thumb, its minimal size should be approximately equal to the diameter of the pole face. Thin sheets may get saturated.

– Use a clamp meter to measure current. Low current reading suggests a voltage drop or a relatively high resistance of the circuit.

– Allow the coil to cool between uses if magnets are used infrequently. Hot coil increases resistance, which decreases magnetic force accordingly.

3 The magnet overheats or burns out

– Check whether the actual duty cycle is lower than stated. Reduce working time and add forced cooling (e.g., a fan).

– Do not exceed rated voltage of the coil (e.g., using 120V on a 24V coil is a danger not only to the coil, but it will increase temperature and destroy the coil eventually).

– For AC magnets, a continuous movement of the armature, if it is present, can result in high current draw and burning the coil.

4. Residual magnetic force doesn’t allow to release the part

– Apply reverse voltage temporarily (DC magnets only), and then release.

– Use an air blast or simply lift the part manually.

– Always use genuine spare parts; otherwise, it may prevent the releasing of the part.