Created on:2022-02-24 09:53

Fault analysis and troubleshooting of electromagnetic directional valve - burning electromagnet

Fault analysis and troubleshooting of electromagnetic directional valve - burning electromagnet

1. Cause analysis.

1) Because the slide valve is stuck, the iron core of the AC electromagnet cannot be sucked to the bottom and burned.

2) The reversing frequency of the electromagnet is too fast and burns out the electromagnet.

3) The enamelled wire of electromagnet coil did not use the specified insulating paint, and the coil was burnt out due to poor insulation.

4) Error in power design or use. When the AC and DC electromagnets are mixed, exceeding the variation range of the allowable voltage and long-term use under the condition of overvoltage, the two electromagnets of the three position valve are connected (or designed) into a path at the same time in the circuit, and the DC power rectifier device fails, the coil can be burned out.

5) High ambient temperature. If direct sunlight, oil temperature, high room temperature, poor ventilation and other reasons will cause coil aging.

6) The insulation paint peels off or the coil is bruised, the plastic sheath of the coil outgoing line is aged, resulting in leakage short circuit, or the coil is burned due to the processing quality of other aspects of the electromagnet.

7) Ambient water vapor, water droplets and corrosive gas penetrate into the electromagnet, as well as other insulation damaging gases and conductive dust enter the electromagnet, causing the coil to be damaged by moisture, rust and damage.

8) Improper selection of working oil, high viscosity and large viscous resistance, which exceeds the load range of electromagnet, resulting in overload and burnout.

9) There is a problem with the design of the hydraulic circuit. If the back pressure of the circuit is too high, it is used under the condition of exceeding the allowable back pressure for a long time, there is no oil drain channel with oil drain hole on the mounting plate, or the oil drain hole is blocked, resulting in blocked oil drain and increased pressure, the electromagnet cannot push the valve core, resulting in overload and burning the coil.

10) The rigidity of the return spring is too large, and the spring force is greater than the suction of the electromagnet due to wrong installation, which leads to the overload and burning of the electromagnet hardtop.

11) Due to the different force of the electromagnet installed on the valve body, the suction direction of the electromagnet is inconsistent with the moving direction of the valve core and burned out.

12) The assembly and cleaning of solenoid valve are not clean; The fit gap between the valve core and the valve body is too small and the valve mounting screw is pressed too tightly, resulting in the deformation of the valve body hole and increasing the friction in the moving direction of the sliding pair of the valve core; Or there are inclusions in the oil, the valve core is stuck and other reasons, resulting in the overload and burning of the electromagnet.

2、       Troubleshooting.

1) Check whether the machining accuracy of the valve is poor and whether there is burr or taper in the valve core and valve hole, which makes the slide valve stuck. Repair or replace the electromagnet according to the actual situation.

2) The specified frequency for the solenoid valve is 2000 times / AC, which is enough for the current standard purpose.

3) The inspection requires that the insulation grade of electromagnet coil shall be above grade E.

4) Pay attention to wiring errors during circuit design or installation of wiring; The coil voltage of electromagnet shall not exceed 85% ~ 105% of the rated voltage of coil; In the unit where the power generation of self owned factory (diesel engine power generation) and the grid voltage are often unstable, the circuit should preferably have a regulated power supply; Note that the voltage of the circuit actually connected shall be consistent with the voltage on the nameplate, and DC and AC shall not be mixed.

5) Check the reasons for the high ambient temperature and ensure that the working environment is within the range of medium temperature not higher than + 50 ℃ and not lower than 30 ℃ specified by the electromagnet manufacturer, so as to make the electromagnet work reliably.

6) Replace the electromagnet or rewind the coil in time.

7) If the environment is bad and the relative humidity is high, the wet tropical electromagnet shall be used. The requirement of this electromagnet for the relative humidity of the ambient air shall be greater than 95%, while the ordinary electromagnet shall not be greater than 85%.

8) Generally, the oil viscosity range of electromagnet shall be l5-400cst according to the data recommendation.

9) Redesign the hydraulic circuit according to the actual situation and replace the electromagnet at the same time.

10) Replace the appropriate spring and replace the electromagnet at the same time.

11) Replace the electromagnet with a new one and install it as required.

12) Take corresponding measures according to the actual situation.

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