Mini-WDT sweep frequency response analyzer uses frequency analysis to evaluate whether a transformer has suffered mechanical damage and complies with IEC60076-18.
Meet IEC 60076-18 standard
Portable and light-weight for easy use
Analysis software allows further diagnostics
Reproducible results thanks to innovative connection technique
DRT3XXL series automated six-winding transformer ohmmeter delivers full eight-terminal resistance measurement capability. Widely used in field testing of CT\PT power transformer windings, verifying factory winding resistance test results, etc.
Built-in printer
Built-in auto-demagnetization
DC test current up to 20A(DRT-320L)、40A(DRT-340L)
One-time connection principle results in faster setup time eliminating safety risk
Automated eight-terminal/six-winding measurement capability
Simultaneous winding magnetization for fast and accurate dc winding resistance measurements of high inductive loads
A portable transformer ohmmeter with an accuracy of ±(reading×0.2%+2) can be used to test transformers, shunt reactors, etc. for low current resistance measurement.
DC test current up to 10A
5.6-inch color LED screen
Built-in battery(Optional)
Wide measurement range (500uΩ ~ 50kΩ) and high accuracy
DC test current up to 20A, 40A, and 50A for different models
7-inch full-color touch display for easy operation and viewing
Auto resistance-rate calculation at 5s, 15s, and 30s intervals
Ground-wire disconnection alarm function (DCR40/DCR50 only)
The three-phase transformer winding analyzer can perform polarity validation, turns ratio and winding resistance tests with the same one-time lead connection.
With TTR and winding resistance tests
TTR, range up to 10000,±0.1 % accuracy
Save time and protect operators with efficient one-time lead connection for tests
Battery powered
The TRT-20 is designed to test all power, instrument (CTs and PTs), and distribution transformers without the need of traditional high voltage excitation.
Built in printer
Battery powered(Optional)
Displays % error vs. name plate value
3-phase test voltage-fast testing of all transformers
The STRT-100 is designed to test all power, instrument (CTs and PTs), and distribution transformers without the need of traditional high voltage excitation.
Portable to carry
Built in printer
Battery powered (optional)
Displays % error vs. name plate value
DRT-340L 40A Automated Six-Winding Transformer Ohmmeter adopts a one-time connection design, has built-in degaussing function, and three-phase balance analysis to provide a reliable and efficient test solution for the field.
Built-in auto-demagnetization
Built-in printer
DC test current up to 20A or 40A (optional)
The DRT series of automated six-winding transformer ohmmeters delivers full eight-terminal resistance measurement capability. It's designed to save you time by testing all normal six windings without having to disconnect and reconnect leads during testing.
Built-in auto-demagnetization
Built-in printer
DC test current up to 20A or 40A (optional)
The HDRT-310 is an automatic hand-held battery operated transformer ohmmeter, allows the user to operate the test set while holding it in one hand. It offers 3 test channel up to 10A with a range from 500µΩ to 50kΩ.
Battery operated
Lightweight – 1.6 kg
Handheld design, easy to carry
One button test, no need to select current
Ability to show three phase winding resistance balance
Electrical integrity testing evaluates the overall condition of electrical equipment by assessing the health of insulation systems, windings, and electrical circuits. Common test parameters include:
Insulation Assessment
Insulation resistance (IR)
AC and DC withstand voltage tests
Dissipation factor (tan δ)
Winding Evaluation
Winding resistance
Transformer turns ratio (TTR)
Fault Detection
Inter-turn insulation condition
Winding balance and phase-to-phase resistance deviation
Winding deformation analysis
Tap changer contact resistance
Additional Diagnostic Parameters
Excitation current
No-load losses
Ground continuity testing
Together, these measurements provide a comprehensive assessment of equipment condition and reliability.
Electrical integrity testers are commonly used for equipment that contains windings, insulation systems, or electrical circuits, including:
Power and distribution transformers
Dry-type and oil-immersed transformers
Electric motors and generators
Current transformers (CTs) and voltage transformers (VTs)
Reactors and inductive coils
Renewable energy converters and associated magnetic components
Switchgear components containing electromagnetic assemblies
These tests help verify performance, detect defects, and support preventive maintenance programs.
Routine integrity testing helps identify developing problems before they become major failures.
Benefits include:
Early detection of insulation deterioration, moisture ingress, and winding defects
Identification of loose connections, tap changer problems, and winding deformation
Monitoring of insulation aging trends through historical test data
Reduction of overheating, short circuits, and catastrophic failures
By detecting issues at an early stage, maintenance can be planned proactively, helping maximize transformer reliability and service life.
Testing intervals vary depending on equipment criticality, operating environment, and maintenance requirements.
Ratio and winding resistance tests are commonly performed:
Before commissioning new transformers
During scheduled preventive maintenance programs
After major repairs or tap changer replacement
Following short-circuit events, lightning incidents, or abnormal operating conditions
Before returning long-idle transformers to service
Asset owners should follow applicable industry standards and maintenance practices when determining test frequency.
A transformer turns ratio (TTR) test compares the actual voltage ratio of transformer windings with the rated ratio specified on the nameplate.
The test is used to identify:
Shorted turns
Open-circuit windings
Incorrect tap changer positions
Wiring and connection errors
Manufacturing or installation defects
TTR testing is a standard procedure during transformer commissioning, maintenance, and troubleshooting.
Yes. Transformer winding resistance measurements are typically performed using a dedicated winding resistance tester rather than a standard multimeter.
Specialized instruments offer:
Stable constant-current injection
Fast charging of inductive windings
Automatic demagnetization functions
Rapid discharge protection
Higher accuracy for low-resistance measurements
These features improve measurement reliability and significantly reduce testing time, especially for large power transformers.
Winding resistance testing is recommended:
During factory acceptance and commissioning tests
As part of routine preventive maintenance
After transformer repairs or winding replacement
Following tap changer maintenance
After short-circuit, overload, or lightning-related incidents
When abnormal temperature rise or unusual operating conditions are detected
Before equipment is returned to service after long-term storage
Regular testing helps verify winding integrity and detect developing faults before they affect equipment performance.
Please tell us your testing requirements, application scenarios or project details, and our engineers will recommend the solution and quotation that suits you within 24 hours.
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