Why Choose the ABB 1SAZ741201R1040 TF42-7.6B Thermal Overload Relay?
The ABB 1SAZ741201R1040, also designated the TF42-7.6B, is a compact and reliable thermal overload relay for railway applications. It is designed to protect motors against sustained overloads and phase failure while meeting the demanding environmental requirements of railway rolling-stock equipment.
Three bimetal tripping elements monitor the current flowing through the motor circuit. When an overload or phase-failure condition causes excessive heating, the relay operates its auxiliary contacts so the associated contactor can disconnect the motor before damaging temperatures are reached.
With an adjustable current range of 5.70–7.60 A and a Class 10 tripping characteristic, the TF42-7.6B supports motors with normal starting duties. Temperature compensation, selectable automatic or manual reset, a trip-free mechanism and dedicated test and stop functions simplify reliable integration into railway motor-control assemblies.
Key Advantages
- Reliable motor protection against overload and phase failure.
- Designed for demanding railway rolling-stock applications.
- Adjustable 5.70–7.60 A current setting range.
- Class 10 tripping characteristic for normal motor starting duties.
- Selectable automatic or manual reset supports different control requirements.
- Compact design integrates directly with compatible ABB contactors.
Key Features
- ABB TF42-B railway thermal overload relay series.
- Three-pole electromechanical construction.
- Adjustable thermal range of 5.70–7.60 A.
- Class 10 tripping characteristic.
- Three bimetal tripping elements.
- Temperature-compensated overload protection.
- Phase-failure sensitivity.
- 1 normally closed trip contact and 1 normally open signal contact.
- Automatic or manual reset selection.
- Integrated stop, test and trip-indication functions.
Reliable Motor Protection for Railway Equipment
Thermal overload relays protect motors by responding to the heating effect created by excessive current. If the configured current is exceeded for long enough, the bimetal elements operate the relay contacts and cause the motor contactor to open, helping prevent damage to the motor windings and insulation.
The TF42-7.6B is engineered for railway rolling-stock applications where vibration, temperature changes and demanding operational conditions require dependable components. Its phase-failure sensitivity provides additional protection when one phase of a three-phase supply is interrupted or becomes severely unbalanced.
Typical Applications
- Railway rolling-stock motor-control systems.
- Train ventilation and air-conditioning equipment.
- Railway pumps, fans and compressors.
- Door, actuator and auxiliary drive systems.
- Rail vehicle electrical control panels.
- Industrial motor starters requiring railway-compliant components.
