Transformer DC Resistance And Turns Ratio 2 In 1 Tester

Weshine, a professional manufacturer from China, provides high quality Transformer DC Resistance And Turns Ratio 2 In 1 Tester, which performs two core verification procedures for power transformers: winding DC resistance test and turns ratio test.

● DC resistance checks: poor contact points, winding internal defects, tap-changer malfunctions, loose connections and unbalanced phase-to-phase resistance.

● Turns ratio testing: validates whether actual transformer ratio, tap position and vector group match nameplate and design specifications.

The integrates both critical test functions within a single instrument. Field crews no longer need to transport two separate testers. Once high-voltage and low-voltage test leads are hooked up, multiple test items can be completed without repeated wiring changes.

DC resistance measurement

For DC resistance measurement, the unit enables three-phase simultaneous testing together with automatic magnetization.

● For star-configured windings with neutral point, A0, B0 and C0 phase resistances can be captured concurrently to shorten overall test cycles.

● When testing three-phase five-limb transformers with internal delta connections, the built-in automatic excitation mode further boosts testing efficiency on low-voltage sides.

Test Results & Protection

Test results for high-voltage, medium-voltage and low-voltage windings can be displayed and printed directly on site.

● Automatically computes three-phase resistance unbalance.

● Outputs resistance readings converted to rated temperature.

● Provides complete, audit-ready transformer test records.

● Comprehensive back-EMF protection safeguards operators during DC resistance discharge and test lead handling.

Turns Ratio Measurement

On turns ratio measurement, the Transformer DC Resistance and Turns Ratio 2 in 1 Tester supports both single-phase and automatic three-phase winding tests.

● Operators select the corresponding transformer connection group.

● Measures ratio value, ratio error and connection-group parameters across AB, BC and CA phases.

● Single-phase turns ratio measurement can finish in approximately 15 seconds as documented in the official manual.

Operation & Data Management

User interaction runs on a 7-inch colour touch LCD with bilingual Chinese-English on-screen prompts.

● Test reports can be generated instantly via the embedded micro printer.

● All datasets can be saved onto USB flash drives and organised by test date and transformer serial number.

● Hardware communication options cover isolated RS232, Bluetooth and internal RS485 bus interfaces.

Technical Parameters

Product Guide

Before operating the Transformer DC Resistance and Turns Ratio 2 in 1 Tester, confirm the target transformer is fully de‑energised, safely discharged and properly earthed. Always connect the instrument protective earth terminal prior to attaching any test clips.

For DC resistance testing, attach high‑voltage and low‑voltage current‑potential clips to corresponding transformer bushings. For two‑winding transformers, wire terminals A, B, C, O and a, b, c, o following wiring schematics. For single‑phase transformers, connect relevant high‑side and low‑side terminals as per diagram. Power on the tester with AC 220 V supply. Navigate through touch‑screen menus to input transformer ID, winding material, test mode, current range, winding parameters and temperature conversion settings, then launch DC resistance or turns ratio measurement.

When running turns ratio tests, select accurate connection group and tap‑changer information to ensure correct ratio, error and vector‑group outputs. If reverse‑polarity connection, short‑circuit condition or wiring fault is detected, halt testing immediately and inspect all test leads before resuming work. Upon test completion, review readings on‑screen. Print hard‑copy reports when required, store records internally or export datasets to USB flash drive for later report compilation.

Features

1、Supports transformer DC resistance and turns ratio testing in one instrument.

2、Measures three-phase DC resistance simultaneously.

3、Measures transformer ratio, ratio error, and vector group.

4、Provides automatic magnetization for DC resistance testing.

5、Provides automatic excitation method for internally delta-connected three-phase five-limb transformers.

6、Automatically calculates three-phase resistance unbalance.

7、Displays and prints high-voltage, medium-voltage, and low-voltage winding test data.

8、Calculates resistance values converted to rated temperature.

9、Supports single-phase and three-phase transformer ratio measurement.

10、Detects high-voltage and low-voltage reverse connection during ratio testing.

11、Detects transformer short-circuit and inter-turn short-circuit conditions during ratio testing.

12、Includes comprehensive back EMF protection.

13、Provides 7-inch color touch-screen operation.

14、Includes built-in micro printer for field test reports.

15、Supports USB storage for external data backup.

16、Provides isolated RS232 communication and Bluetooth communication.

17、Includes Chinese and English menu prompts.

Application Scenarios

The Transformer DC Resistance and Turns Ratio 2 in 1 Tester serves transformer manufacturers for pre‑shipment validation of winding DC resistance, phase unbalance, turns‑ratio error and vector group. One single unit fulfils two mandatory factory‑test requirements and simplifies equipment preparation and test documentation workflows for production teams.

For power utilities and substation operators, this diagnostic tester applies to new‑unit installation, hand‑over acceptance, scheduled maintenance and fault troubleshooting. Winding resistance data exposes potential tap‑changer contact wear and abnormal phase resistance deviation; turns‑ratio results verify tap position and connection‑group correctness.

Within transformer repair workshops, technicians rely on this Tester to assess winding status after rewinding, drying treatment or tap‑changer overhaul. Pre‑repair and post‑repair resistance & turns‑ratio datasets can be compared to verify transformers return to acceptable operating condition.

For field commissioning crews, the all‑in‑one design cuts down the quantity of test equipment transported to sites. Built‑in printing, USB archiving and transformer‑ID‑based data sorting generate well‑structured records for project acceptance documents and end‑customer deliverables.

Applications

The Transformer DC Resistance & Turns Ratio 2‑in‑1 TTR Tester is widely adopted by transformer OEMs, power utility operators, substation maintenance crews, electrical commissioning contractors, transformer repair workshops, industrial power departments and high‑voltage test service providers.

Typical test subjects include power transformers, distribution transformers, single‑phase & three‑phase transformers, two‑winding and three‑winding transformers, star‑connected windings, delta‑connected windings, on‑load tap‑changing transformers, instrument mutual inductors, generators, electric motors and other low‑resistance wound equipment.

Common industry search aliases for overseas SEO & B2B sourcing: transformer diagnostic tester, DC winding resistance tester, transformer turns ratio tester, transformer TTR tester, transformer ratio and winding resistance tester, transformer vector group tester, transformer maintenance test instrument.

Customer Case

One transformer maintenance contractor needed higher‑efficiency distribution‑transformer testing during substation power‑outage windows. Previously their field crew operated separate DC resistance tester and turns‑ratio tester, which brought frequent repeated wiring changes and disjointed record‑keeping for every transformer unit.

By deploying the Transformer DC Resistance and Turns Ratio 2 in 1 Tester all‑in‑one tester, both winding DC resistance and turns‑ratio & vector‑group tests can be completed with one instrument. After proper earthing and lead installation, technicians capture three‑phase winding resistance readings, evaluate phase balance, then proceed to turns‑ratio and vector‑group checks without re‑routing test cables.

During one maintenance assignment, DC resistance output flagged abnormal phase deviation under a specific tap position. The team then utilised the integrated TTR function to cross‑check tap setting and connection group, localising the root cause to defective tap‑changer contact. Printed hard copies and USB‑saved digital records were directly appended to official maintenance reports.

Adopting this combined tester reduced on‑site setup labour hours, improved cross‑test data consistency and smoothed overall transformer inspection workflows for field‑service technicians.

FAQ

Q1: What is this Tester used for?

A1: It performs transformer winding DC resistance measurement together with transformer turns ratio and vector group verification.

Q2: Can this Tester test three‑phase resistance at the same time?

A2: Yes. It supports simultaneous three‑phase DC resistance testing, offering 10 A, 5 A and 1 A selectable current ranges.

Q3: What is the maximum DC resistance test current?

A3: For individual‑phase DC resistance testing, maximum test current reaches 20 A.

Q4: What is the DC resistance measurement accuracy?

A4: Official manual specifies Class 0.2 measurement accuracy with 0.1 μΩ reading resolution.

Q5: What is the transformer ratio measurement range?

A5: Turns‑ratio measuring range covers 1 up to 10000.

Q6: Can it measure transformer vector group?

A6: Yes. It identifies transformer connection groups, supporting common configurations including YY, YD, DD and DY as listed in user documentation.

Q7: How fast is the ratio test?

A7: According to product manual, single‑phase turns‑ratio test can complete within roughly 15 seconds.

Q8: Does it support data printing and export?

A8: Yes. This Tester comes with embedded micro printer and USB storage for external test‑result archiving.

Q9: What communication interfaces are included?

A9: Hardware interfaces contain isolated RS232, Bluetooth and internal RS485 bus communication.

Q10: What safety protections are included?

A10: Protection mechanisms include back‑EMF safeguard for DC‑resistance testing, high‑low‑voltage reverse‑connection detection, plus short‑circuit and inter‑turn‑fault alarm during ratio measurement.

Weshine Advantages

Weshine Electric supplies professional transformer test instruments and electrical diagnostic equipment for utilities, transformer manufacturers, substations, field contractors, repair workshops and industrial maintenance teams.

For this Tester Transformer DC Resistance & Turns Ratio 2‑in‑1 TTR Tester, Weshine supports global customers with model selection consultation, practical test‑method guidance, technical parameter confirmation, project‑ready documentation and complete after‑sales service.

Transformer testing demands error‑free wiring, stable low‑resistance acquisition, accurate ratio validation and strict hazard control after DC‑resistance measurement. This Tester consolidates two indispensable transformer inspection workflows in one hardware unit, equipped with touch‑screen operation, automatic calculation, on‑site printing, multi‑mode data storage and diversified communication capabilities.

Why Choose Weshine

• Direct factory supply of high‑performance transformer diagnostic test equipment

• Pre‑sales technical consultation and post‑sales global technical support

• Tailored solutions for power utilities, test contractors and maintenance service providers

• Rich project experience supporting international bidding, on‑site commissioning and equipment resale partners

For overseas end‑users and distributors, Weshine provides full product documentation and application support for transformer maintenance jobs, substation commissioning, factory acceptance testing, tender preparation and operator training. This Tester is a practical all‑in‑one transformer tester built for both field site and in‑workshop deployment.