Excavator solenoid valve TM70202 24V hydraulic pump proportional solenoid valve

The working principle of the solenoid valve:

The solenoid valve uses an electromagnet to push the valve core to control the direction of compressed air, thereby controlling the direction of the pneumatic actuator switch.

Its advantage is simple operation, easy to achieve remote control.
Electromagnetic directional valve according to different requirements can achieve two three-way, two five-way and so on.

The electromagnet used to operate the solenoid valve is divided into AC and DC:
1. The voltage of AC electromagnet is generally 220 volts. It is characterized by large starting power, short reversing time and low price. However, when the valve core is stuck or the suction is not enough and the iron core is not sucked on, the electromagnet is easy to burn out due to excessive current, so the working reliability is poor, the impact of action, and the life is low.
2, DC electromagnet voltage is generally 24 volts. Its advantages are reliable work, not because the spore is stuck and burned out, long life, small size, but the starting power is smaller than the AC electromagnet, and in the absence of DC power supply, the need for rectification equipment.

 System pressure can't go up at all

Reason 1:
① The main spool damping hole is blocked, such as the assembly of the main spool is not cleaned, the oil is too dirty or the assembly with debris;
② Poor assembly quality, poor assembly accuracy during assembly, poor adjustment of the gap between valves, the main spool stuck in the open position, poor assembly quality;
③ The main spool reset spring is broken or bent, so that the main spool can not be reset.
The solution:
① Disassemble the main valve cleaning damping hole and re-assemble;
② Filter or replace the oil;
③ Tighten the valve cap fastening screw to replace the broken spring.

Cause 2: The pilot valve is faulty
① The adjusting spring is broken or not loaded,
② Taper valve or steel ball is not installed,
③ The taper valve is broken. Solution: Replace the damaged parts or replace the parts to restore the pilot valve to normal work.

Cause 3: The remote control port solenoid valve is not powered on (normally open) or the slide valve is stuck
Solution: Check the power line to see if the power supply is connected; If normal, it indicates that the slide valve may be stuck, and the faulty parts should be repaired or replaced.