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Precautions when using cooling fan around power switch circuit (prevent electric corrosion)
- Categories:News
- Author:rain
- Origin:capital
- Time of issue:2021-06-29 14:33
- Views:
(Summary description)When the cooling fan is installed near the high-power switch circuit such as UPS, inverter, rectifier, high-voltage power supply or high-voltage switch circuit, due to the strong electromagnetic interference (electromagnetic induction) generated by the circuit or the high-frequency interference generated by the power line of the cooling fan, the induced current may be generated in the bearing of the fan shaft, The oil film on the bearing surface is damaged, and the bearing and rolling surface of the bearing are damaged. This phenomenon is called "electric erosion of fan". After the occurrence of electric erosion, the rotation of the fan becomes not smooth, and abnormal sound is emitted when rotating, and the service life becomes shorter. With the development of high-density packaging, the distance between the switch circuit and the fan becomes shorter and the switching frequency increases, which makes the fan more vulnerable to electromagnetic induction. In the low voltage operation of information / communication equipment, due to the small electromagnetic interference, there will be no electric erosion phenomenon.
Precautions when using cooling fan around power switch circuit (prevent electric corrosion)
(Summary description)When the cooling fan is installed near the high-power switch circuit such as UPS, inverter, rectifier, high-voltage power supply or high-voltage switch circuit, due to the strong electromagnetic interference (electromagnetic induction) generated by the circuit or the high-frequency interference generated by the power line of the cooling fan, the induced current may be generated in the bearing of the fan shaft, The oil film on the bearing surface is damaged, and the bearing and rolling surface of the bearing are damaged. This phenomenon is called "electric erosion of fan". After the occurrence of electric erosion, the rotation of the fan becomes not smooth, and abnormal sound is emitted when rotating, and the service life becomes shorter. With the development of high-density packaging, the distance between the switch circuit and the fan becomes shorter and the switching frequency increases, which makes the fan more vulnerable to electromagnetic induction. In the low voltage operation of information / communication equipment, due to the small electromagnetic interference, there will be no electric erosion phenomenon.
- Categories:News
- Author:rain
- Origin:capital
- Time of issue:2021-06-29 14:33
- Views:
When the cooling fan is installed near the high-power switch circuit such as UPS, inverter, rectifier, high-voltage power supply or high-voltage switch circuit, due to the strong electromagnetic interference (electromagnetic induction) generated by the circuit or the high-frequency interference generated by the power line of the cooling fan, the induced current may be generated in the bearing of the fan shaft, The oil film on the bearing surface is damaged, and the bearing and rolling surface of the bearing are damaged. This phenomenon is called "electric erosion of fan". After the occurrence of electric erosion, the rotation of the fan becomes not smooth, and abnormal sound is emitted when rotating, and the service life becomes shorter. With the development of high-density packaging, the distance between the switch circuit and the fan becomes shorter and the switching frequency increases, which makes the fan more vulnerable to electromagnetic induction. In the low voltage operation of information / communication equipment, due to the small electromagnetic interference, there will be no electric erosion phenomenon.
Examples of electric erosion
After installing a fan without erosion protection near the inverter control equipment and other electromagnetic interference components, confirm that the fan has erosion phenomenon.
|
No. |
purpose |
Time of producing abnormal sound |
|
1 |
Switching power supply / rectifier | 6 months to 2 years |
|
2 |
UPS |
6 months to 2 years |
|
3 |
General purpose inverter |
1~1.5 years |
|
4 |
Air cleaner |
23 months |
|
5 |
Inverter for LCD |
6 months |
Mode 1 of electrical erosion
1. Due to the high frequency interference (electromagnetic field) generated by the switch circuit, the high frequency wave flowing to the fan is generated, which makes the fan live.
2. When the fan is electrified, the charge flows through the bearing to generate current.
3. The electric current destroys the oil film on the surface of the bearing and the bearing is worn.
4. This phenomenon is easy to occur in high-speed and high-density packaging equipment with switch circuits.
5. Countermeasure 1: install the shield plate inside the fan.
6. Countermeasure 2: please choose the fan with ceramic bearing.
Mode 2 of electric erosion
1. The high frequency components generated by the circuit board enter into the fan through the power line.
2. The incoming high frequency current flows through the bearing.
3. The oil film on the bearing surface is damaged and the bearing is worn (electric erosion).
4. Countermeasure 1: remove the high frequency component between the fan power supply terminals A-B, A-E and B-E, or insert a filter into the fan power line.
5. Countermeasure 2: please choose the fan with ceramic bearing.
6. In order to reduce the induction of the fan power cord, please wind up the wiring.
Note: shielded metal plate
If electromagnetic shielding metal plate is needed, our company has "EMC protective cover", and installing ordinary fan cover inside the fan can also play a certain shielding effect. However, make sure that it is connected to the housing ground.
Note: filter
If the high frequency interference is superimposed on the AB line in phase, please insert the common mode filter; If not, insert normal mode filter.
Countermeasures against electric corrosion
1. When designing the equipment, please keep the fan away from the electromagnetic interference source.
2. Please select the "anti erosion fan" with ceramic bearing.
3. Please install the "EMC shield" on the common cooling fan.
4. Please connect the fan power cord from the circuit without overlapping interference.
Although the EMC shield has a good effect on the electromagnetic interference caused by radiation, we recommend to use yamayo's "anti erosion cooling fan" when shielding the strong electromagnetic interference (electromagnetic induction) and the interference generated by the transmission through the fan power line.
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