Application Scenarios

In a water treatment plant in Taiyuan, this relay is installed in a motor control center (MCC) protecting a 45 kW cooling water pump motor. It monitors the three-phase current. If the pump gets clogged, causing the current to rise to 120% of the set value for over 30 seconds, the TA200 DU90 automatically opens its control contact, dropping the contactor and shutting down the pump before the motor windings overheat.

 

Parameter

Main Parameters	Value/Description
Product Model​	TA200 DU90​
ABB Order Code​	3BHE010751R0101​
Rated Operational Voltage​	690 V AC​
Setting Current Range​	66 – 90 A​ (Continuously adjustable dial)
Trip Class​	10A​ (Standard trip characteristic for normal starting motors)
Number of Poles​	3
Auxiliary Contacts​	1 NO (97-98) + 1 NC (95-96)
Reset Mode​	Manual / Automatic (Selectable via side lever)
Ambient Temperature​	-25 °C to +55 °C (Ambient compensated)
Mounting​	Direct clip-on to ABB A-line contactors (e.g., A75, A80) or single mounting kit
Protection Features​	Overload, Phase Failure (Unbalance)

 

 

Technical Principles and Innovative Values

• Innovation Point 1: Ambient Temperature Compensation for Stable Protection:​ Unlike basic thermal relays whose trip point drifts with cabinet temperature, the TA200 DU90 features automatic ambient temperature compensation. This means whether your Taiyuan facility is in a hot summer (+40°C) or a cold winter (-10°C) environment, the relay’s trip current remains stable relative to the motor’s actual thermal capacity. This prevents nuisance tripping in heat or under-protection in cold weather.
• Innovation Point 2: Trip-Free Mechanism for Safety:​ The relay incorporates a trip-free mechanical design. Once it trips due to an overload, even if the reset button is held down forcibly, the contacts will not re-close until the bimetallic strips have cooled down and the fault is cleared. This “mechanical memory” ensures the motor cannot be restarted prematurely into a fault condition, protecting both the motor and the operator.
• Innovation Point 3: Integrated Phase Failure Protection:​ The relay’s design provides inherent phase loss/unbalance protection. If one phase of the motor supply is lost, the increased current in the remaining phases causes the bimetallic strips to heat up asymmetrically, triggering a faster trip than a balanced overload. This protects the motor from single-phasing damage, a common cause of motor failure in industrial settings.

 

Application Cases and Industry Value

Case 1: Coal Mine Ventilation Fan, Shanxi Province.​ A mine ventilation fan driven by an 80A motor was protected by a TA200 DU90. During a period of high dust concentration, the fan blade imbalance led to a gradual current rise. The relay’s Class 10A characteristic allowed the motor to start under heavy load (high inertia) without tripping, but reliably disconnected it after 2 minutes of sustained overload, preventing a catastrophic motor seizure and ensuring mine air quality safety.Case 2: Steel Plant Conveyor System.​ In a continuous casting conveyor, multiple TA200 DU90 relays were used. The manual reset mode (selected via the side lever) was enforced as a safety procedure. After an overload trip, maintenance personnel were required to physically inspect the conveyor belt for jams before pressing the reset button, enforcing a “lockout-tagout” discipline and preventing remote automatic restarts into a dangerous condition.