The DOSSENA T154 is a microprocessor‑based thermal control unit designed to prevent insulation degradation caused by overheating in resin‑encapsulated medium‑voltage transformers, dry‑type transformers, motors, generators, and generating sets. It continuously monitors up to four independent temperature measurement points through three‑wire Pt100 RTD sensors and activates configurable dual‑level alarms when temperature thresholds are exceeded. The LED display provides immediate visual indication of measured temperatures and alarm status at the front panel, while the IP54‑rated flush‑mount enclosure allows installation in industrial control cabinets exposed to dust and moisture.

Thermal Protection for Critical Electrical Infrastructure

• Insulation Aging Prevention: The primary function of the T154 is to detect and react to overtemperature conditions before they accelerate insulation degradation. In dry‑type transformers, a sustained temperature increase of just 10 °C above rated limits can halve the expected insulation life. The T154’s dual alarm levels provide both an early‑warning alarm at a lower threshold, allowing operators to take preventive action, and a second‑level alarm that can be wired to trigger an automatic disconnection if the temperature continues to rise beyond the critical limit. This staged protection is suitable for un‑manned substations where operator intervention is not guaranteed.
• 3 or 4 PT100 Inputs – Flexible Configuration: The unit can accept 3 or 4 PT100 RTD sensors, each with three‑wire connection to compensate for cable resistance. The 3‑input version typically monitors the three phase windings of a single transformer, while the 4‑input version adds a core temperature measurement point or accommodates monitoring of a second transformer or motor.
• Equal Alarm Levels for All Inputs: Both alarm thresholds are identical for all connected measurement channels, ensuring that any phase reaching the critical temperature triggers protection regardless of which sensor detects the temperature rise. This eliminates the risk of localised hotspots being missed by asymmetric alarm configurations.

Microprocessor‑Based Control and Alarm Management

• Microprocessor Electronic Technology: Built according to modern technical standards, the T154 uses microprocessor‑based electronics to provide reliable, drift‑free temperature monitoring and alarm management. The digital processing eliminates the calibration drift and mechanical wear associated with older electromechanical thermal relays.
• Compliance and Quality: Manufactured in Italy under ISO 9001 quality management systems and RINA certified for marine and industrial applications, the T154 also complies with CE directives for industrial electrical equipment. It maintains ease of use alongside high quality standards, consistent with the DOSSENA product family philosophy.
• Front Panel Status Indication: The LED display provides an immediate visual indication of measured temperatures and alarm status without requiring additional instrumentation. Alarms are clearly signaled, enabling rapid operator response even in noisy or dimly‑lit substation environments.

Applications

• Resin‑encapsulated medium‑voltage transformer winding temperature monitoring and alarm
• Dry‑type transformer thermal protection in industrial plants, data centres, and commercial buildings
• Large industrial motor and generator stator winding temperature surveillance
• Emergency and standby generating set thermal monitoring for critical infrastructure
• Any electrical machine application where insulation thermal degradation must be prevented through early warning and automatic protection