Digital Multimeter Tests for Inductors & Transformers
Digital multimeters mainly have commonly used measurement functions such as DC voltage, DC current, AC voltage, AC current, resistance, circuit on/off testing, and testing; With the development of electronic technology, multimeters have many application functions such as data storage, data transmission, and oscilloscope. Some of them have developed into professional application fields, including power meters for testing, leakage current testers, insulation resistance testers, infrared thermometers used in industrial and mining industries, noise meters for environmental testing, anemometers, etc. Taking the UT58C handheld ordinary digital multimeter from Ulide Company as an example, let's talk about the knowledge of using a multimeter. UT58C is a 3L/2-digit digital multimeter, but in addition to voltage, current, and resistance testing functions, it also has functions such as frequency, diode, and on/off buzzer hFE, Temperature measurement, with its unique large screen display and input prompt functions, also brings a lot of convenience to users.
Detection methods for inductors and transformers in digital multimeters:
1. Detection of color coded inductors
Place the multimeter in the R × 1 position, and connect the red and black probes to either lead of the color code inductor. At this point, the pointer should swing to the right. According to the measured resistance value, it can be distinguished into the following three situations:
The resistance value of the tested color code inductor is zero, indicating an internal short-circuit fault. The magnitude of the DC resistance value of the tested color code inductor at port B is directly related to the diameter of the enameled wire used to wrap the inductor coil and the number of turns wound. As long as the resistance value can be measured, it can be considered that the tested color code inductor is normal.
2. Inspection of Zhongzhou Transformer
Set the multimeter to the R × 1 position and check the on/off status of each winding one by one according to the pin arrangement pattern of the mid cycle transformer, in order to determine if it is normal.
B-port insulation performance testing
Place the multimeter in the R × 10k range and perform 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.
