The initial transformer turns ratio (TTR) testing was conducted using a simple bridge method, such as the Maxwell or Heaviside bridges. These early devices required a series of complex, separate components—standard resistors, inductors, and galvanometers—making the testing process time-consuming, labor-intensive, and prone to calculation errors (left side of the bottom picture).
The development of transformer turns ratio (TTR) testers dates back to the early 20th century, with the hand-cranked transformer ratio testers developed by James G. Biddle，operators needed to generate excitation voltage by turning a hand-cranked generator on the side while adjusting a knob until the galvanometer pointer zeroed out (zero-balance method), and then reading the turns ratio from the scale on the knob (right side of the top picture).
By the late 20th century, the advent of microprocessors led to the creation of digital TTR testers, these devices automated the excitation and balance processes, displaying readings on an LCD screen instantly and eliminating human errors. Modern devices are now fully automated, capable of testing all three phases simultaneously, measuring phase shift and excitation current, and offering wireless data logging capabilities, from the bulky, hand-cranked wooden testers to the handheld high-precision computers, TTR testers have continuously evolved to meet the demands of the increasingly complex global power grid.
The JYT TTR is a new-generation transformer turns ratio tester that incorporates a high-precision multi-core ARM CPU (Advanced RISC Machines, USA), delivering outstanding measurement accuracy and resolution. Weighing only 1.6 kg, the JYT is perfectly suited for both field use and extended testing applications.
Equipped with a robust built-in lithium battery, it supports over 800 test cycles on a single charge. Compact and highly portable, the instrument is fast, efficient, and precise, with a rapid test time of just 1.2 seconds.
The JYT TTR is an ideal solution for variable turns ratio testing across power generation, transmission and distribution, substations, industrial facilities, and transformer manufacturing environments.
1.JYT is equipped with a powerful built-in lithium battery, suitable for field testing, and can perform more than 800 tests on a single charge.
2.It has 8 connection poles, meeting the requirements for transformer turns ratio testing, from distribution transformers to power transformers, current transformers (CT), voltage transformers (PT), and Z-type connection transformers.
3.JYT features a 5.6-inch color, high-brightness touch screen, allowing the tester to be used both indoors and outdoors.
4.It includes a mechanical key for "run/stop".
5.JYT is equipped with a battery monitoring and protection function.
6.It has a "flash disk" interface for exporting data and a Bluetooth communication function.
7.JYT turns ratio tester features high and low voltage reverse connection protection, transformer short circuit protection, and inter-turn short circuit protection.
JYT Technical Specification
|
TYPE |
JYT Hand held TTR |
|
Ratio Range |
0.9-10000 |
|
Minimum Resolution |
0.0001 |
|
Accuracy |
±0.1%（ ratio value <500） |
|
Output Voltage |
Max. 35V/50Hz |
|
Battery Endurance: |
≥ 800 tests per full charge (Quick Mode) |
|
Data Storage Capacity |
100 sets |
|
Operation Temperature |
-20℃ ~40℃ |
|
Relative Humidity |
≤80%, No condensation |
|
Dimensions (L × W × H) |
L210mm x W150mm x H70mm |
|
Net Weight |
Approx.1.6 kg |
JYT turns ratio tester Demo Video
Three Phase Connection
Single Phase Connection
Unlike traditional flip-cover testers, the JYT features an open-end terminal design, allowing test leads to connect in any direction. This prevents cable bending, ensures accurate results, and makes setup faster in tight spaces — ideal for frequent field testing.
It’s designed for power, distribution, CT, PT, and OLTC transformers across multiple voltage levels.
Kingrun Transformer Instrument Co.,Ltd.
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