Transformer Factory Series Testers

  • Portable Transformer DC Winding Resistance Tester KRI 9310
Portable Transformer DC Winding Resistance Tester KRI 9310

Portable Transformer DC Winding Resistance Tester KRI 9310

  • 10A output can test extremely low resistance 1μΩ~20kΩ
  • Original Japanese NEC integrated chip with 0.1%±0.5μΩ accuracy
  • Auto Temerature Conversion for CU/AI objects
  • Cover 80% power transformer with 500 tims testing by one charge
  • Product description: KRI9310 adopt Kelvin four-wire testing method, it can measure very low resistance(0.01Ω) with accuracy(±0.5μΩ), specially developed for power transformers, KRI9310 has long working time and easy porta

Why DC Winding Resistance Testing of Transformers is Needed?

The DC resistance of the transformer refers to the DC resistance value of each phase winding, and the purpose of measuring the DC resistance is as follows:

1. Check the welding quality of the wires and leads inside the transformer windings.
2. Check whether the winding or lead wire is broken.
3. Check the correctness of the parallel branch, whether there is one or several disconnections in the winding formed by several parallel wires;
4. Check whether there is a short circuit between layers and turns of the transformer.
If there is a phase-to-phase short circuit inside the transformer, the short-circuit current value is very large, and it is easy to burn the transformer. By measuring the DC resistance of each phase and comparing the three-phase resistance values, it is easy to judge whether there is an inter-turn short circuit inside: the resistance value varies greatly, the possibility of inter-turn short-circuit fault is very high.

KRI 9310 DC winding resistance tester Application Test Objects:

KRI 9310 adopt Kelvin four-wire testing method, which effectively eliminates the influence of the resistance of the test line on the test results. It can be able to increases the current to 10A by which can test extremely low resistance to 0.01 Ω(such as amorphous alloy, Copper-nickel, nickel-chromium-iron, iron-chromium-aluminum etc). For the tested objects with high resistance value (CT/PT), the instrument can extend the range to 20 kΩ,so the wide resistance test  range enables KRI9310 can cover 80% of the power transformer products on the market and switchgear bus-bar cable etc. The power of the tester use the built-in rechargeable lithium battery that can test hundreds of transformers by one time charging.


KRI 9310 it is provided with the temperature conversion function. By selecting test sample material(copper/aluminum) and temperature from tester, the instrument can be able to automatically convert them to the resistance values under the standard temperature (20℃,75℃,120℃). KRI 9310 is also provided with the data storage function, 500 groups of experimental data can be stored within the instrument. Also KRI 9310 has USB interface, the data can be downloaded to flash disc.


Tester type

KRI 9310

Scope of application







Test range









Minimum resolution


Built-in battery

11.1V ; Capacity:4500mmAh

Standard conversion temp.


Temperature test range

-99.9~199.9℃ ; Accuracy: ±0.5% (JYR9311 only)

Volume / weight

Length 155 mm Width 210 mm Height 68 mm /1.66 kg

JYR9310 Transformer Winding Resistance Testing Connection:

CALIBRATION CERTIFICATE of KRI 9310 DC winding resistance tester FROM ILAC.MRA(The world's most stringent calibration testing agency)

Testing sites of JYR-9310 DC winding resistance tester:

Demo Video:

The 5 most popular manufacturers of DC resistance testers in the world:

Megger turns ratio tester (USA) DV Power turns ratio tester (Sweden) Kingrun turns ratio tester (China)

Hightest winding resistance tester (UK) Raytech winding resistance tester (USA)

All Kingrun Testers will be Delivered by International Air Express for Free!

Now we have promotion activity as below:

1. Buy any Kingrun tester, will get a KEW2200 clamp meter for Free!!

2. You will get 5% discount by online inquiry(just click the green”INQUIRY”bottom and put into your specific inquiry).

3. 2 Years warranty period. Whole lifetime maintenance.

4. 24h online technical support.