Why do electromagnets generate over heating during using? Causes and solutions?

Many people will find that the electromagnet heats up quickly and the magnetic force decreasing slowly during using. What exactly causes this? How to avoid this kind of problem happened?​

Part 1 : Why Solenoid heats quickly and force decrease slowly

during application ?

Many people will find that the electromagnet heats up quickly and the magnetic force decreasing slowly during using.  What exactly causes this? How to avoid this kind of problem happening?​

Hot temperature of a solenoid may cause harm to the equipment and the high temperature will reduce the insulation performance of the electromagnet. Over heating will accelerate the aging of the material, and long-term high temperature will shorten the life of the electromagnet; On the other hands, it may burn out the coil and even cause a fire. Therefore, precaution must be taken to deal with the high temperature problem of electromagnets.

Reason for heating: When the working voltage is stable, the value of the resistor is too small. The over heating of a solenoid may cause by

1.1 Circuit failure: Problems such as circuit interruption, poor contact, etc., cause the electromagnet to be overloaded and the temperature rising.

1.2 Excessive loading: The electromagnet bears an excessive load and works for too long, causing the overheating of the electromagnet.

1.3 Poor cooling system : the construction of electromagnet has the poor heat dissipation system will cause the temperature rises.

1.4 High Voltages

In rare cases, a solenoid coil will burn out due to high voltage. The plunger closes easily due to the solenoid has extra force, but high voltage causes excessive holding current, which overheats the coil gradually and burns insulation on the magnet wire.  

1.5 Damage

Finally, a solenoid may hammer itself to pieces — evidenced by mechanical damage and breakage. Excessive force may be caused by overvoltage or by a reduced load on the solenoid and must be absorbed when the plunger hits the C-stack or field.

Part 2 : How to deal with the over heating of an electromagnet?

2.1 Check the wiring

When the electromagnet is running, it is necessary to regularly check whether the circuit connection is firm to avoid problems such as circuit interruption and poor contact. At the same time, check whether the cross-sectional area of the wire meets the current requirements. If the wire is too thin, it may easily cause the circuit to be overloaded, thus affecting the normal operation of the electromagnet.

2.2 Reduce loading

If it is found that the temperature of the electromagnet is too high due to excessive loading, the load needs to be reduced or the electromagnet needs to be replaced. When selecting and designing electromagnets, Solenoid size should be considered to avoid the overloading and overheating of the magnets.

2.3 Increase cooling

For those electromagnets that work for a long time or are in an environment with high ambient temperature, cooling measures can be used, such as ventilation, water cooling, etc. to achieve cooling.

2.4 the working environment

If the working environment is much higher than the electromagnet specification and the working pressure is too tight, as well as the power supply voltage is too bad will cause over heat and other problems accordingly.

For such problems, the application should be adjusted reasonably according to the requirements.

2.5 Poor quality problem of the Solenoid Coil

the overheat problem caused by the quality of the solenoid valve coil itself,  it should be replaced with a qualified solenoid valve coil in time.

Part 3: Our Solution to avoid over heating  

Since we have 20 years experience in DC solenoid project, we will do the four key element to avoid the over heating problem.

3.1 Strengthen the insulation: Choose high-quality insulating materials to make insulators to avoid aging and wear of insulators. Installing insulating gaskets or using insulating tape to strengthen the insulation.

3.2. Optimize circuits: Design reasonable circuits, match resistance and inductance values, avoid excessive external voltage, and choose appropriate power supplies.

3.3. Reduce operating temperature: According to actual needs, temperature tests can be performed and reasonable power can be set. Reducing current or changing voltage can reduce the operating temperature of the electromagnet.

3.4  Avoid electromagnetic interference: When the electromagnet works at the same time as other electrical equipment, isolation equipment, shielding covers and other measures can be used to reduce external interference.

3.5  During product development, we will do the lifespan testing and do the valuation checking according to the specification agreement. If some problem happy during testing, we will check and select the right action immediately to avoid the problem that may happy during application.

https://www.drsolenoid.com/8-key-elements-of-dc-solenoid-design-guide/  Pls check this link to know our design technical guide for a DC solenoid.

Part 4 Summary

When the electromagnet has the over heating problems, you need to  check the circuit, reducing the load, and increasing cooling to deal with it and pay attention to the working environment as well as the solenoid coil quality.

At the same time, when design and select an electromagnets, factors such as solenoid size, loading, the force of the push and pull need to be taken into consideration to avoid electromagnet overheating problems in advance.