Type of wire coil toroidal winding machine 7

(1) When selecting and using inductive coils, we should first think about the inspection and measurement of coils, and then judge the quality and advantages and disadvantages of coils. In order to accurately detect the inductance and quality factor Q of inductive coils, special instruments are generally required, and the test method is complex. In practical work, this kind of detection is generally not carried out, but only the on-off inspection of coils and the size of Q value Judgment. [1] First measure the DC resistance of the coil with the resistance gear of the multimeter, and then compare it with the original determined resistance or nominal resistance. If the measured resistance is much larger than the original determined resistance or nominal resistance, Even the pointer doesn't move (the resistance value tends to infinity x) it can be judged that the coil is broken; if the measured resistance value is very small, it can be judged that it is a serious short circuit or a local short circuit, which is difficult to compare. In these two cases, it can be judged that the coil is bad and can not be used. If the measured resistance is not different from the original determined or nominal resistance value, it can be judged that the coil is good. In this case, we can judge according to the following: In this case, judge the quality of the coil, that is, the size of the Q value. When the inductance of the coil is the same, the smaller the DC resistance is, the higher the Q value is; The larger the diameter of the wire used, the larger the Q value; If multi strand winding is adopted, the more strands of conductor, the higher Q value; Coil frame (or iron core) the smaller the loss of materials used, the higher the Q value. For example, when high silicon silicon steel sheet is used as iron core, its Q value is higher than that when ordinary silicon steel sheet is used as iron core; the smaller the coil distributed capacitance and magnetic leakage, the higher the Q value. For example, the Q value of honeycomb wound coil is higher than that of flat winding, which is also higher than that of random winding; when the coil has no shielding cover and there are no metal components around the installation position, its Q value is higher If the value is high, on the contrary, the Q value is low. The closer the shield or metal component is to the off-line coil, the more serious the Q value decreases; The position of magnetic core shall be properly arranged; The antenna coil and the oscillation coil shall be perpendicular to each other, which avoids the influence of mutual coupling.

(2) The coil shall be visually inspected before installation

Before use, check whether the structure of the coil is firm, whether the wire turns are loose and loose, whether the lead contacts are loose, whether the magnetic core rotates flexibly, whether there are sliding buckles, etc. After these aspects are checked and qualified, the installation can be carried out.

(3) If the coil needs fine adjustment during use, the fine adjustment method shall be considered

Some coils need to be fine tuned during use, and it is inconvenient to change the number of coils. Therefore, the method of fine tuning should be considered when selecting. For example, a single-layer coil can use the method of removing the trapped coil near the end point, that is, 3 ~ 4 turns are wound around one end of the coil in advance. During fine adjustment, the inductance can be changed by moving its position. Practice shows that this regulation method can fine tune the inductance of ± 2% - ± 3%. For coils used in short wave and ultrashort wave circuits, half a turn is often reserved for fine adjustment. Move or turn this half turn to change the inductance and realize fine adjustment. The fine adjustment of multi-layer segmented coil can be realized by moving the relative distance of one segment, and the number of turns of the movable segment shall be 20% - 30% of the total number of turns. Practice has proved that this fine-tuning range can reach 10% - 15%. For a coil with a magnetic core, the coil inductance can be fine tuned by adjusting the position of the magnetic core in the coil tube.

(4) When using the coil, pay attention to maintaining the inductance of the original coil

Do not change the shape of the coil when the coil is in use. Size and distance between coils, otherwise it will affect the original inductance of the coil. In particular, the higher the frequency, that is, the fewer coils. Therefore, the high-frequency coil used in TV is generally sealed and fixed with high-frequency wax or other dielectric materials. In addition, it shall be noted that during maintenance, the position of the original coil shall not be changed or adjusted at will, so as to avoid detuning fault.

(5) The adjustable coil shall be installed for easy adjustment

The adjustable coil shall be installed at the easily adjustable position of the machine, so as to adjust the inductance of the coil to achieve the best working state