Excavator parts Sany 215j 135 75-89 solenoid valve coil

Coils are usually composed of skeleton, winding, magnetic core and shielding cover, etc. According to different occasions, some coils have no shielding cover, some have no magnetic core, and some have no fixed frame, only windings.

Step 1: skeleton

The commonly used materials of skeleton are ceramics, plastics, bakelite and electrical cardboard. The material of the skeleton has a certain influence on the quality and stability of the coil, which is generally selected according to the working conditions.

2. Winding

Most windings are made of insulated wires wound on the bobbin. Insulated wires are commonly used with enameled wires and electromagnetic wires of various specifications. Generally speaking, the greater the inductance required by the winding, the more the number of windings. The diameter of the selected wire should be determined according to the current value passing through the winding and the Q value of the coil. When the current passing through is large and the Q value is required to be high, the diameter of the coil wire should be selected to be thicker. When the inductance is less than a few microhenres, the winding is usually wound with bare silver-plated copper coins to reduce the surface resistance of the wire and improve the performance of the coil.

3. Shield

In order to reduce the influence of the external electromagnetic field on the coil and the contribution of the electromagnetic field generated by the coil to the external circuit, a metal cover is often used to enclose the coil in the structure, and it is reliably grounded to achieve the requirement of isolation from the external circuit.

4. Magnetic core

After the coil is put into the core, the inductance of the coil can be increased, or compared with the coil without the core with the same inductance, the number of coils with the core can be reduced, thus reducing the volume and distributed capacitance of the coil and improving the Q value of the coil. Sometimes, in order to adjust the inductance of the coil, it can be realized by adjusting the position of the core in the coil. Magnetic cores are usually made of manganese-zinc ferrite or nickel-zinc ferrite magnetic materials, and can be made into various shapes according to different requirements of use.