In the early 20th century, transformer DC resistance testing primarily relied on basic bridge circuits. Due to the very low resistance and high inductance of transformer windings, the Kelvin double bridge became the standard method for measuring sub-ohm resistances and eliminating the effects of lead resistance, these early "testers" were not single devices but assemblies made of brass and wooden components, including sensitive galvanometers, large-capacity batteries, and manual sliding resistors, operators had to wait several minutes until the transformer core's large inductance saturated before obtaining stable readings. By the mid-20th century, these components were integrated into portable wooden box bridge devices. While more convenient, they still required manual balancing and complex temperature correction. The digital revolution of the 1980s introduced the "current-source" method, utilizing stable DC power supplies and microprocessors to calculate resistance through Ohm's Law (R = V/I). Modern testers are now equipped with high-speed discharge circuits that safely dissipate stored magnetic energy, along with automatic temperature compensation and multi-phase testing functions, transforming the cumbersome manual process into a quick one-button diagnostic.

The JYR-10S incorporates the ARM (Advanced RISC Machines; USA) high-precision multi-core CPU, offering stable performance and high computational accuracy. It is suitable not only for power distribution transformers, transformers, electrodedicators, electromagnetic operating mechanisms, and other inductive test products, but also for measuring impedance in products such as cables, breaker contacts, and relay contacts.

For dry transformers and amorphous alloy transformers, where the low-voltage coil is made of copper foil and the resistance value is very low, the instrument increases the current to 10A to address the challenge of low-value resistance measurement. At the same time, for high-resistance test products such as transformers, the instrument extends the range to 100kΩ.

JYR-10S is powered by a rechargeable lithium-ion battery and utilizes advanced power management technology, allowing it to measure hundreds of transformers on a single charge.

Function Introduction:

1.The JYR-10S winding resistance tester features an insulated shell, is sealed, anti-leakage, and resistant to wind and sand. It has soft rubber corners for shock absorption protection.
2.It is suitable for measuring the resistance of transformers, motors, and other inductive test products, as well as copper rows, wires, switch contacts, and other resistance test products.
3.The tester can automatically test the windings with Yn, Y, D, and other connections in a three-phase simultaneous test, with automatic phase change, automatic determination of data stability, and calculation of the three-phase imbalance rate.
4.Current output options include 10A, 3A, 1A, 300mA, 100mA, 20mA, and automatic modes. The automatic currents cover full-scale testing, with the maximum output current reaching 10A.
5.The resistance measurement range is from 0Ω ~100kΩ.
6.It features a temperature conversion function. By selecting the test material (copper/aluminum) and inputting the temperature (an optional special wireless temperature probe can be used to collect the test temperature directly), the tester automatically converts the measured resistance to the standard temperature for easy comparison with historical data.
7.Up to 100 sets of test data can be stored. It has a USB interface for importing data to a USB drive and a built-in Bluetooth communication module for interaction with a PC or other computers, or to connect to a micro-Bluetooth printer for printing data reports.
8.The "Test/Stop" mechanical button offers shortcuts and an automatic shutdown function after 5 minutes of inactivity.
9.The tester is powered by a built-in rechargeable lithium battery, which allows for hundreds of transformer tests on a single charge. Fully balanced battery charging technology effectively extends the battery life.
10.It is equipped with a high-brightness color touch LCD display, and the touch menu operation is fast and clear.
11.It includes discharge sound alarms, overheat alarms, and other protective circuits, with clear instructions to minimize mishandling.

JYR-10S Operation Interface

JYR-10S DC Resistance Technical Specification

Kingrun Transformer Instrument Co.,Ltd.

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