How to measure the inductance coil during maintenance

1. Visually check whether the inductor coil is cracked, whether the coil is loose or displaced, and whether the pins are secure. Check whether the nominal value of the inductance is on the surface of the inductor. You can also further check whether the core rotates flexibly and whether there are any slip buckles.

2. Use a multimeter to check the continuity

Measurement of color-coded inductance Set the multimeter to R×1 and touch the pins of the inductor coil with two test leads. When the resistance value of the inductor being measured is 0Ω, it means that the inductor coil is short-circuited internally and cannot be used. If the measured inductor coil has a certain resistance value, it means it is normal. The resistance value of the inductor coil is related to the thickness and number of turns of the enameled wire used in the inductor coil. Whether the resistance value is normal can be compared with the normal value of the same model. When the measured resistance value is ∞, it means that the inductor coil or the pin and the coil contact point are open circuited, and this inductor coil cannot be used.

Measurement of the oscillation coil Since the oscillation coil has a base and pins under the base, first find out which coil each pin is connected to, then use the R×1 range of the multimeter to measure the resistance value of the primary winding or secondary winding. If there is a resistance value and it is relatively small, it is generally considered normal. If the resistance value is 0, it is a short circuit, and if the resistance value is ∞, it is an open circuit.

Since the oscillation coil is placed in a shielding cover, the resistance between the primary and secondary windings and the shielding cover must also be tested. The method is to select the R×10 k position of the multimeter, touch the shielding cover with one test lead, and touch each pin of the primary and secondary windings with the other test lead. If the measured resistance is ∞, it means it is normal. If the resistance is 0, there is a short circuit. If the resistance is less than ∞ but greater than 0, it means there is a leakage.

3. Measurement of color-coded inductors Set the multimeter to R×1, and connect the red and black test leads to any lead-out terminal of the color-coded inductor. The pointer should swing to the right. According to the measured resistance value, it can be identified in the following three situations: (1) The resistance value of the color-coded inductor is zero, and there is a short-circuit fault inside. (2) The DC resistance value of the color-coded inductor is directly related to the diameter of the enameled wire used to wind the inductor coil and the number of windings. As long as the resistance value can be measured, the color-coded inductor can be considered normal.

4. How to distinguish color-coded inductors and resistors

First, the resistor is long and thin, while the inductor is short and thick. Second, the two ends of the resistor are slightly larger, while the inductor is cylindrical.