How to measure inductance with a multimeter
Inductor and transformer testing methods and experience
1? Detection of color-coded inductors
Put the multimeter in the R×1 block, and connect the red and black test pens to any terminal of the color-coded inductor. At this time, the pointer should swing to the right. According to the measured resistance value, it can be identified in the following three situations:
A? The resistance value of the tested color-coded inductor is zero, and there is a short-circuit fault inside. B? The DC resistance value of the tested color-coded inductor is directly related to the diameter of the enameled wire used to wind the inductor coil and the number of turns. As long as the resistance value can be measured, the tested color-coded inductor can be considered normal. of.
2. Detection of mid-week transformer
A? Turn the multimeter to the R×1 gear, check the on-off status of each winding one by one according to the pin arrangement of each winding of the mid-cycle transformer, and then judge whether it is normal. B? Test insulation performance
Put the multimeter in the R×10k block, and do the following state tests:
(1) The resistance value between the primary winding and the secondary winding;
(2) The resistance value between the primary winding and the casing;
(3) The resistance value between the secondary winding and the casing.
The above test results are divided into three situations:
(1) The resistance value is infinite: normal;
(2) The resistance value is zero: there is a short-circuit fault;
(3) The resistance value is less than infinity, but greater than zero: there is a leakage fault.
3. Detection of power transformers
A? Check whether there is any obvious abnormality by observing the appearance of the transformer. Such as whether the coil lead is broken, desoldered, whether the insulating material has scorch marks, whether the iron core tightening screw is loose, whether the silicon steel sheet is rusted, whether the winding coil is exposed, etc.
B? Insulation test. Use the multimeter R×10k block to measure the resistance values between the core and the primary, the primary and each secondary, the core and each secondary, the electrostatic shielding layer and the secondary, and the secondary windings. The pointer of the multimeter should point to infinity. move. Otherwise, the transformer insulation performance is poor.
