What Is a Transformer Winding Temperature Indicator?
A transformer winding temperature indicator is a temperature monitoring instrument used on oil-immersed transformers. It indicates the winding temperature condition by combining transformer oil temperature measurement with load-related thermal simulation.
The sensing bulb is installed in the transformer oil pocket to measure oil temperature. When the transformer load increases, the instrument uses a current-related heating element to simulate winding temperature rise. This allows the dial to show a practical winding temperature value for transformer operation, alarm and cooling control.
Product Positioning
This product is suitable for transformer winding temperature indication, oil-immersed transformer temperature monitoring, WTI temperature controller applications, oil temperature gauge projects, transformer cooling control and remote temperature signal transmission.
How the Transformer Winding Temperature Indicator Works
The indicator uses transformer oil temperature as the base temperature. Under load, transformer winding temperature is usually higher than oil temperature. To reflect this condition, the instrument adds a simulated temperature rise based on transformer load current.
Oil Temperature Sensing
The temperature sensing bulb is inserted into the oil pocket on the transformer tank. It detects the oil temperature and transfers the temperature change to the dial mechanism through the capillary system.
Winding Temperature Simulation
The instrument receives a load-related current signal and generates additional heat inside the measuring system. This simulated temperature rise helps the indicator reflect the winding thermal condition.
Alarm and Trip Output
Built-in switch contacts can be used for over-temperature alarm, trip signal, fan start, fan stop or other transformer protection logic.
Remote Temperature Output
The 4-20mA output can transmit temperature data to a remote indicator, PLC, transformer control cabinet or monitoring platform.
Technical Specifications
| Specification Item | Standard Configuration |
|---|---|
| Product name | Transformer Winding Temperature Indicator |
| Typical model | BWR-04/06AJ(TH) |
| Application | Oil-immersed transformer winding temperature indication and control |
| Output signal | J-DC 4-20mA current signal |
| Working power supply | AC220V ±10%, 50-60Hz |
| Working conditions | Ambient temperature -40°C to +55°C, relative humidity ≤100%, altitude ≤2000m |
| Temperature measurement range | Default 0-150°C, optional 0-160°C |
| Accuracy | Class 1.5, maximum allowable detection point error ±2.25°C |
| Switching error | ±2°C |
| Switch rated power | AC220V / 5A, DC220V / 3A |
| Protection level | IP55 |
| Temperature bulb size | Φ14 × 150mm |
| Mounting thread | M27 × 2mm |
| Capillary length | 5m |
Main Functions
Winding Temperature Indication
The instrument indicates the transformer winding thermal condition by combining oil temperature sensing and load-related heating simulation.
Local Dial Reading
The dial display allows operators to check transformer winding temperature directly on site during inspection and maintenance.
Alarm Contact Output
Switch contacts can be used for over-temperature alarm, trip signal, fan control or transformer protection circuit requirements.
Cooling Control
The instrument can support cooling fan start and stop control according to preset temperature points and transformer control design.
Remote Monitoring Signal
The 4-20mA output can send temperature data to a remote display, PLC, transformer temperature controller or monitoring system.
Product Structure
| Part | Function |
|---|---|
| Dial Indicator | Displays transformer winding temperature locally |
| Temperature Sensing Bulb | Installed in the transformer oil pocket to sense oil temperature |
| Capillary Tube | Transfers temperature change from the sensing bulb to the indicator body |
| Heating Simulation Unit | Simulates winding temperature rise according to transformer load condition |
| Switch Contacts | Outputs alarm, cooling control or protection signals |
| Current Output Module | Provides 4-20mA signal for remote temperature monitoring |
WTI and Oil Temperature Gauge Application
WTI means Winding Temperature Indicator. In oil-immersed transformer applications, a WTI instrument is used to indicate the winding thermal condition rather than only the oil temperature. It is commonly used with alarm contacts and cooling control circuits.
The transformer oil temperature gauge function provides the base temperature from the oil pocket. The winding temperature indication is then formed by adding load-related thermal simulation. This makes the instrument suitable for transformer operation protection and temperature controller systems.
| Function | Purpose | Typical Output |
|---|---|---|
| Oil Temperature Sensing | Provides base oil temperature from the transformer oil pocket | Dial indication |
| Winding Temperature Simulation | Reflects load-related winding temperature rise | WTI indication |
| Alarm Setting | Warns operators when temperature reaches preset threshold | Switch contact |
| Trip Setting | Supports transformer protection when temperature is too high | Trip contact |
| Remote Monitoring | Sends temperature data to external monitoring equipment | 4-20mA signal |
Typical Applications
Oil-Immersed Power Transformer
The indicator is used for winding temperature indication, over-temperature alarm and cooling control on oil-immersed power transformers.
Distribution Transformer
For distribution transformers, the instrument provides local temperature reading and remote signal output for routine operation monitoring.
Transformer Cooling Control Cabinet
The switch contacts and 4-20mA signal can be connected to a transformer control cabinet for fan control, alarm and temperature protection logic.
Substation Transformer Monitoring
The product can provide winding temperature indication and remote output for substation operation, maintenance and transformer protection systems.
Transformer Temperature Controller Project
The instrument can be used in transformer temperature controller applications where local display, alarm contacts and current output are required.
How to Select the Right Transformer Winding Temperature Indicator
Confirm Transformer Type
Check whether the instrument will be used on a power transformer, distribution transformer or special oil-immersed transformer.
Confirm Temperature Range
Select the proper range according to transformer operating temperature, alarm setting and protection requirement.
Confirm Mounting Interface
Check the oil pocket size, mounting thread and sensing bulb depth before selection.
Confirm Capillary Length
Select the capillary length according to the distance between the transformer oil pocket and the instrument mounting position.
Confirm Output Requirement
Confirm whether the project needs switch contacts, 4-20mA output, remote display or control cabinet connection.
Confirm Cooling Control Logic
Define alarm, trip, fan start and fan stop settings according to transformer control requirements.
Recommended Information for Selection
| Required Information | Example |
|---|---|
| Transformer type | Oil-immersed power transformer or distribution transformer |
| Temperature range | 0-150°C or 0-160°C |
| Output requirement | Switch contact, 4-20mA output, remote display or control cabinet connection |
| Mounting interface | Thread size, oil pocket position and sensing bulb depth |
| Capillary length | Standard length or customized installation distance |
| Control function | Alarm, trip, cooling fan start, cooling fan stop or remote monitoring |
Frequently Asked Questions
What is a transformer winding temperature indicator?
It is an instrument used on oil-immersed transformers to indicate winding temperature condition based on oil temperature measurement and load-related thermal simulation.
What does WTI mean?
WTI means Winding Temperature Indicator. It is used to indicate transformer winding temperature and support alarm or cooling control.
Is this product a fiber optic temperature sensor?
No. This product is a conventional transformer winding temperature indicator and is not related to fiber optic temperature measurement.
What is the purpose of the 4-20mA output?
The 4-20mA output is used to transmit temperature data to a remote display, transformer control cabinet or monitoring system.
Can it control transformer cooling fans?
Yes. The switch contacts can be used for cooling fan control according to transformer control circuit design.
Where is the sensing bulb installed?
The sensing bulb is usually installed in the oil pocket on the transformer tank.
What should be confirmed before ordering?
Transformer type, temperature range, mounting thread, sensing bulb size, capillary length, output signal and control function should be confirmed.
Transformer Winding Temperature Indicator for Oil-Immersed Transformer Protection
The transformer winding temperature indicator provides winding temperature indication, alarm output, cooling control and remote signal transmission for oil-immersed transformers. It is suitable for WTI temperature controller projects, transformer control cabinets, substation monitoring systems and transformer over-temperature protection applications.
