How to distinguish the positive and negative poles of the four holes of the solenoid reversing valve

The four holes (P, T, A, B) of the solenoid directional valve themselves do not involve the distinction between positive and negative poles. Their function is to control the flow direction of the fluid, not the direction of the current. Here is a detailed explanation:

Functions of the four holes of the solenoid directional valve

Port P (pressure oil source): connected to the outlet of the hydraulic pump to provide pressure oil for the system.

T port (tank return): connected to the fuel tank for oil return.

Port A and Port B: are respectively connected to the actuator (such as the two chambers of the hydraulic cylinder), and the oil circuit is switched on and off and the flow direction is changed through the valve core switching.

Working principle of solenoid directional valve

The electromagnetic directional valve uses an electromagnet to drive the displacement of the valve core and switch the direction of the oil circuit, thereby controlling the movement direction of actuators such as hydraulic cylinders or motors. For example, when the electromagnet is energized, the valve core moves to make P→A, B→T, and the actuator moves in the forward direction; otherwise, P→B, A→T, and the actuator moves in the reverse direction.

The relationship between the electromagnetic reversing valve and the positive and negative poles

Electromagnet part: The electromagnet part of the electromagnetic reversing valve may involve the distinction between positive and negative poles, but this has nothing to do with the functions of the four holes. The positive and negative poles of the electromagnet are usually determined by the wiring method of the coil, and some solenoid valves may need to distinguish the positive and negative poles due to the presence of internal rectification circuits or indicator lights (such as light-emitting diodes).

Function of the four holes: The function of the four holes is to control the flow direction of the fluid, regardless of the direction of the current. Therefore, there is no need to consider the positive and negative poles of the four holes when installing or using the solenoid directional valve.