ABB TA25DU-5.0M Thermal Overload Relay

Заказ №.: 1SAZ211201R2035

TA25DU-5.0M is a 3-phase bimetallic тепловое реле перегрузки in the TA25DU ряд. The M variant is designed for AX series контакторы (non‑M versions fit A series contactors). It provides motor overload and phase failure protection.

✅ Core Technical Parameters

Регулируемый диапазон тока: 3.5 ~ 5.0 А

Класс поездки: 10А (standard motor protection)

Rated main circuit voltage: 690 В переменного тока / DC 440V

поляки: 3-защита полюса

Вспомогательные контакты: 1НЕТ + 1Северная Каролина (one changeover contact)

Режим сброса: Руководство / Automatic reset selectable

Built-in functions: Температурная компенсация, защита от обрыва фазы, кнопка тестирования, STOP function, индикация отключения, механизм без срабатывания

Compatible contactors: AX09, AX12, AX18, AX25 (direct plug-in mounting)

Автономный монтаж: Requires separate mounting base as an accessory

📌 Type Code Definition

ОБЛИЦОВКА: Тепловое реле перегрузки

25: Frame rated current 25A

ИЗ: Universal bimetallic type

5.0: Maximum setting current 5A

М: Version for AX contactors (differentiated from older TA25DU-5.0 for A contactors)

📋 Typical Applications

Protection for 0.75~2.2kW 3-phase asynchronous motors (380В), applied on machine tools, фанаты, водяные насосы, conveyors and compressors. It forms a motor starter circuit together with АББ AX contactors.

⚠️ Выбор & Рекомендации по замене

1. Замена той же серии: TA25DU-5.0 (older version for A contactors; pin layout differs and cannot be directly interchanged)
2. Отечественные альтернативы: Вкусный, Chint thermal relays with 3.5–5A range (verify contact configuration, trip class and mounting base)
3. Координация: Short-circuit protection shall be implemented with fuses or circuit breakers. This relay only provides overload & защита от обрыва фазы, not short-circuit protection.

📎 Auxiliary Contact Ratings (АС-15)

400В: NC 0.75A, NO 0.37A

240В: NC 3A, NO 1.2A

120В: NC 3A, NO 1.5A

Operating Principle of ABB TA25DU Bimetallic Thermal Overload Relays

Основной принцип: Thermal effect of electric current + differential bending of bimetallic strips; inverse-time overload & защита от обрыва фазы. It only works with contactors for motor overload protection and cannot protect against short circuits.

1. Basic 3-phase Structure

Each phase is equipped with: heating element + биметаллическая полоса. Additional components: differential slide plate, temperature compensation strip, quick-trip mechanism, 1НО+1НЗ вспомогательные контакты (95/96 Северная Каролина, 97/98 НЕТ), setting knob, reset mechanism and test button.

Биметаллическая полоса: Two metals with different thermal expansion coefficients bonded together; it bends toward the lower-expansion side when heated.

2. Нормальная работа

Three-phase current equals the set value. Heat generation is low, and the bimetallic strip only bends slightly, not enough to trigger the trip mechanism. The 95-96 NC contact remains closed, the contactor coil stays energized, и мотор работает нормально.

3. Защита от перегрузки (Inverse-time Characteristic)

Sustained motor overload → current exceeds setting → heating element keeps rising in temperature, and the bimetallic strip bends further with accumulated heat.

Once the deformation threshold is reached, the quick-trip mechanism releases, тот 95-96 НЗ контакт открывается, the ABB contactor coil de-energizes, main contacts break and the motor stops.

Особенность: Характеристика обратнозависимого времени: Higher overload current leads to faster tripping. Short starting inrush current will not cause false tripping (Класс отключения 10А, standard rating for TA25DU series), simulating the thermal inertia of motor windings.

4. Обрыв фазы (Потеря фазы) Защита (Built-in Differential Mechanism on TA25DU)

When three-phase current is unbalanced or one phase is lost:

The open phase carries nearly zero current; its bimetallic strip cools down and springs back.

The other two phases draw much higher current, and their bimetallic strips keep bending.

The differential slide plate amplifies the deformation difference, triggering tripping much faster than regular balanced overload protection. This prevents motor burnout due to phase loss, a standard feature on ABB DU-series thermal relays.

1) Direct Cross-Brand Equivalent (TA25DU-5.0M, 3.5~5А)

2) Full Series Cross Reference Table (TA25DU-M vs Competitors)

Часть 3: Extended Frame Sizes (TAxxDU-M Series)

TA42DU-M: For AX40~AX50 contactors, 25～42A

TA75DU-M: For AX65~AX80 contactors, 25～75A

TA80DU / ТА110ДУ / ТА200ДУ: High-current models (90～200A)

Часть 4: Field Replacement Notes

1. Non-interchangeable base: TA25DU-M only plugs onto AX contactors; older TA25DU fits A contactors. Mismatched mounting will cause loose connection and overheating.
2. Strictly match current range: Select relays with fully overlapping setting ranges; never use higher current ratings to replace lower ones.
3. Защита от обрыва фазы: TA25DU has built-in differential phase-loss protection. Siemens 3RU and Schneider LRD also include this function; confirm this feature before purchasing low-cost domestic models.
4. Режим сброса: Keep manual/automatic reset consistent with the original unit to avoid unintended auto-restart for unattended equipment.

Часть 5: Simplest Replacement Plan for TA25DU-5.0M

Импортировать альтернативы: Schneider LRD07C, Siemens 3RU6116-1FB0

Отечественные альтернативы: Chint NR2-25/Z 5, Delixi CDR6-25 5

OEM same-model replacement: TA25DU-5.0M (Номер заказа. 1SAZ211201R2035)