How do you test the winding resistance of a transformer
mars 25, 2022
Ⅰ: How do you test the winding resistance of a transformer?
Transformer winding resistance measurements are obtained by passing a known DC current through the winding under test and measuring the voltage drop across each terminal (Ohm’s Law).
Winding resistance in transformers will change due to shorted turns, loose connections, or deteriorating contacts in tap changers. Regardless of the configuration, the resistance measurements are normally made phase-to-phase and the readings are compared with each other to determine if they are acceptable.
Ⅱ: Which method is used to measure resistance of winding?
The windings resistance can be directly measured with an ohmmeter. Another method is to calculate the resistance by measuring the current trough every winding, using an ammeter A, when a voltage is applied and measured with a voltmeter V.
Ⅳ: Parameters of the DCR tester/winding resistance tester：
| Item | Parameter | inaccuracy |
| Test current | AUTO、<20mA、40mA、 | |
| 200mA、1A、5A、10A | ||
| Range | 0.5mΩ~0.8Ω (10A) | ±(0.2%+2digit) |
| 1mΩ-4Ω (5 A) | ||
| 5mΩ-20Ω ( 1 A) | ||
| 100mΩ-100Ω (200mA) | ||
| 1Ω-500Ω (40mA) | ||
| 100Ω-100KΩ (<20mA) | ±(0.5%+2digit) | |
| Best Resolution | 0.1μΩ | |
| Display | 7-inch color LCD touch screen | 4 effective digits Resistance display |
| Data Storage | 1000 sets | |
| Operating Temperature | 0℃~40℃ | |
| Relative Humidity | <90%RH,non-condensing | |
| Power supply | AC 220V±10V,50Hz±1 Hz | Fuse 2A |
| Max Power | 200W | |
| Dimension | 360*290*170(mm) | |
| Weight | Instrument box:6 KG | wire box:5 KG |
Here are some pictures when using:
