UHV-321 Transformer Capacity Load No-load Tester

High precision instrument used in transformer capacity, no-load, load and other characteristic parameters measurement

Measure the transformer no-load current, no-load loss; short-circuit voltage, short circuit (load) loss, capacity.
The device can auto check if the wire was correctly connected, and display the vector diagram of three phase current, voltage when test the three phase transformer.
Allow external connecting CT and PT to make extension measurement, can test the specimen with any parameters.

Note: Regarding product purchase, technical maintenance and other services, welcome to send email: send email

Product Introduction

This product is specially used for measuring the capacity of distribution power transformer, measuring the no-load and short-circuit loss of transformer, and has the function of harmonic analysis, which is convenient for analyzing the quality of on-site power network. The device can automatically check whether the wiring is correct and display the vector diagram of the three-phase current and voltage when testing the three-phase transformer. At the same time, necessary correction (such as waveform correction, temperature correction, unrated voltage correction, calibration, unrated current correction) is introduced to make the test results more accurate.

Product names: Transformer Capacity Load No-load Tester, Transformer capacity test instrument, transformer capacity load tester

Product Parameters

Main technical parameters

Capacity measuring range	30kVA~31500kVA
Current measuring range	0-100A auto-switch the measurement range
Current measurement accuracy	±(0.2%+3 digits)
Voltage measurement range	Line Voltage 0-750V; phase voltage 0-450V, auto-switch the measurement range
Voltage measurement accuracy	±(0.2%+3 digits)
Insulation resistance	>100MΩ
Leakage current	<3.5mA
Dielectric strength	the power connection on the chassis can withstand: 1500V External transformer can broaden the scope of measurement instruments
Frequency Range	40~65Hz,accuracy class 0.2
Power Input	AC 220V±10%

Note:

1.The appearance of the product shall be subject to the actual product，Technical parameters with model if there are any changes，without notice.In case of misappropriation or copying, legal liability will be investigated.

2. For more information about Wuhan UHV, please enter product center . Service email: info@hvtest.cc

Product Characteristics

1. Measure the transformer no-load current, no-load loss; short-circuit voltage, short circuit (load) loss, capacity.
2. Test methods: three-table.
3. The device can auto check if the wire was correctly connected, and display the vector diagram of three phase current, voltage when test the three phase transformer.
4. Single machine can make the loading test for substation transformer under 1600KVA; can make the loading test with 1/3 of the rated current for substation transformer under 2500KVA(the device can convert to the loading losses parameters if the rated current under 1/3 of the rated current)
5. All the related test results are automatically corrected. Instrument can automatically such as: the waveform correction, temperature correction, non-rated voltage correction, calibration, and other non-rated current correction, so that more accurate test results.
6. 320x240 LCD, friendly man-machine interface, brilliance control, adapts to all seasons.
7. With electronic clock, auto record the data, time, it is good for saving and managing the test results.
8. Panel type printer can print the test results on site.
9. Data (specimen setting, test results, measurement time) can be saved on power failure and can be reviewed, it can store 500 groups test results, can connect with computers to transmit data.
10. Allow external connecting CT and PT to make extension measurement, can test the specimen with any parameters.

Application Scenarios

1、Transformer Manufacturing and Factory Acceptance
During production and final inspection, manufacturers use the tester to verify that capacity ratings, no‑load losses, short‑circuit (load) losses, and impedance voltage comply with design specifications and national standards.
2、Utility Commissioning and Type Tests
Before energizing new or overhauled transformers in substations, it performs no‑load and load loss tests to ensure the equipment is in good condition and ready for service.
3、Routine Maintenance and Preventive Testing
During scheduled overhauls, it regularly measures core parameters (capacity, no‑load current, load loss, impedance voltage) to detect early signs of insulation aging, winding deformation, or core faults, supporting preventive maintenance decisions.
4、On‑site Capacity Verification and Anti‑Theft Inspection
For transformers with missing or illegible nameplates, the tester can quickly determine their actual rated capacity without external power. This is widely used by utilities and inspection bodies to verify user capacity declarations and detect unauthorized capacity increases.
5、Fault Analysis and Post‑Damage Assessment
After a transformer experiences a short‑circuit fault or lightning strike, measuring load losses and impedance voltage helps assess the severity of winding deformation and evaluate whether the unit can be safely restored to service.
6、Field Troubleshooting and Mobile Testing
With internal battery power and lightweight design, it is well suited for field work in remote areas, industrial plants, mining sites, and temporary test stations, where reliable AC power may not be available.

Common Troubleshooting

1. Boot no display: first off, open the socket on the back panel AC 220V fuse box, check the fuse box, you can replace insurance.
2. The screen suddenly black screen: press the reset button, to start measurement.
3. Measurement and computation results are not correct: Check the external wiring, whether by manual operation, whether bad or take the wrong line; relevant parameter is incorrect.
4. Measuring voltage and current display to zero the normal, check whether the current file fuse blown

Maintenance Responsibility

1. The failure or damage caused by user's drop during use or handling.
2. The failure or damage caused by user's maintenance with other units.
3. The failure or damage caused by the abnormal voltage.
4. The failure or damage caused by the force majeure(such as fire, flood, natural disasters, etc.).
5. The failure or damage caused by the do not follow the requirements of this manual, free to connect to other devices.
6. No warranty card, and because the equipment could not confirm the defective product under warranty.

FAQ

1、What is a Transformer Capacity & Load/No-Load Tester used for?
It is used to measure the rated capacity, no-load loss (iron loss), no-load current, load loss (copper loss), impedance voltage, and short-circuit impedance of distribution and power transformers without requiring external high-power supplies.
2、How to perform a no load test on a transformer?
In this test secondary (usually high voltage) winding is left open, all metering instruments (ammeter, voltmeter and wattmeter) are connected on primary side and normal rated voltage is applied to the primary (low voltage) winding.
3、Why do we do a no load test on a transformer?
The no-load test, also called "no-load loss" or "excitation current test," is conducted by applying rated voltage to the primary winding while the secondary winding is open. The main purpose is to evaluate the core performance, no-load losses, and excitation current of the transformer.
4、Can it test transformers without knowing the rated capacity beforehand?
Yes, this is a key feature. The tester automatically determines the actual capacity of an unknown transformer by comparing measured parameters against internal standard databases (e.g., GB 1094, IEC 60076). This helps detect nameplate mismatches or fraud.
5、What are the after-sales terms?
We provide free consultation services, one-year warranty, and use various methods such as email communication, video calls, and technical on-site visits to promptly solve any after-sales problems.

Product Video

Product Picture

Product attachment drawing

Instrument host

Test pliers(Yellow, green and red)

Product details

The host

The host side

panel

display

Connection area

The key area

The printer

The test interface

carton

Product Certificate

Enterprise products in strict accordance with international and national standards and rules of industry production, through the national, provincial and municipal electric power research institute and electric power authorities detection, measuring center, fully passed the ISO9001 international quality management system certification, the licence for manufacturing measuring instruments of the People's Republic of China, GB/T19001-2016 quality management system requirements, GB/T24001-2016 environmental management system requirements, GB/T45001-2020 occupational health and safety management system requirements.