Solenoid valve is a kind of actuator, which is widely used in mechanical control and industrial valves. It can control the direction of fluid, and control the position of valve core through electromagnetic coil, so that the air source can be cut off or connected to change the direction of fluid flow. The coil plays a key role in it. When the current passes through the coil, electromagnetic force will be generated, which will involve the "electricity" problem, and the coil may also be burnt out. Today, we will focus on the reasons for the damage of electromagnetic valve coil and the methods for judging whether it is good or bad.
1. The fluid medium is impure, which causes the spool to jam and the coil to be damaged.
If the medium itself is impure and there are some fine particles in it, after a period of use, fine substances will adhere to the valve core. In winter, compressed air carries water, which can also make the medium impure.
When the slide valve sleeve and the valve core of the valve body are matched, the clearance is generally small, and one-piece assembly is usually required. When the lubricating oil is too little or there are impurities, the slide valve sleeve and the valve core will get stuck. When the spool is stuck, FS=0, I=6i, the current will increase immediately, and the coil will burn easily.
2. The coil is damp.
Damping of the coil will lead to insulation drop, magnetic leakage, and even burning of the coil due to excessive current. When it is used at ordinary times, it is necessary to pay attention to the waterproof and moistureproof work to prevent water from entering the valve body.
3. The power supply voltage is higher than the rated voltage of the coil.
If the voltage of the power supply is higher than the rated voltage of the coil, the main magnetic flux will increase, so will the current in the coil, and the loss of the core will cause the temperature of the core to rise and burn out the coil.
Causes of solenoid valve damage and judging methods
4. The power supply voltage is lower than the rated voltage of the coil
If the power supply voltage is lower than the rated voltage of the coil, the magnetic flux in the magnetic circuit will decrease and the electromagnetic force will decrease. As a result, after the washer is connected to the power supply, the iron core cannot be attracted, air will exist in the magnetic circuit, and the magnetic resistance in the magnetic circuit will increase, which will increase the excitation current and burn out the coil.
5. Operating frequency is too high.
Frequent operation will also cause coil damage. In addition, if the iron core section is in an uneven running state for a long time during operation, it will also cause coil damage.
6. Mechanical failure
Common faults are: the contactor and the iron core can't close, the contactor contact is deformed, and there are foreign bodies between the contact, the spring and the moving and static iron cores, all of which can cause the coil to be damaged and unusable.
7. Overheating environment
If the ambient temperature of the valve body is relatively high, the temperature of the coil will also rise, and the coil itself will generate heat when running.
There are many reasons for coil damage. How to judge whether it is good or bad?
Judging whether the coil is open or short-circuited: the resistance of the valve body can be measured by multimeter, and the resistance value can be calculated by combining the coil power. If the coil resistance is infinite, it means that the open circuit is broken; if the resistance value tends to zero, it means that the short circuit is broken.
Test whether there is magnetic force: supply normal power to the coil, prepare the iron products, and put the iron products on the valve body. If the iron products can be sucked after being energized, it indicates that it is good, and vice versa, it indicates that it is broken.
No matter what causes the damage of solenoid valve coil, we should pay attention to it, find out the cause of the damage in time, and prevent the fault from expanding.
Post time: Aug-26-2022