ABB 1SAZ741201R1033 TF42-3.1B is a Class 10 railway thermal overload relay with an adjustable 2.30–3.10 A range, phase-failure sensitivity and selectable automatic or manual reset.
£78.17
The ABB 1SAZ741201R1033, also designated the TF42-3.1B, 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 2.30–3.10 A and a Class 10 tripping characteristic, the TF42-3.1B 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.
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 winding and insulation damage.
The TF42-3.1B 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.
| Manufacturer | ABB |
|---|---|
| Series | TF42-B |
| Model | TF42-3.1B |
| Order code | 1SAZ741201R1033 |
| Product type | Railway thermal overload relay |
| Number of poles | 3 |
| Current adjustment range | 2.30–3.10 A |
| Trip class | 10 |
| Tripping elements | 3 bimetal elements |
| Auxiliary contacts | 1 normally closed trip contact and 1 normally open signal contact |
| Reset method | Selectable automatic or manual |
| Short-circuit protection fuse | 10 A gG |
| Protection rating | IP20 |
| Pollution degree | 3 |
| Weight | 0.13 kg |
| EAN | 4013614517129 |
The TF42-3.1B protects motors in railway applications against sustained overloads and phase-failure conditions.
The thermal overload setting can be adjusted between 2.30 and 3.10 A to match the motor’s rated current.
The ABB TF42-3.1B has a Class 10 tripping characteristic suitable for motors with normal starting times.
Yes. The relay allows the installer to select either automatic or manual reset according to the control-system requirements.
The relay includes one normally closed trip contact and one normally open signal contact for contactor control and fault indication.
ABB TF42-B thermal overload relays provide dependable overload and phase-failure protection for railway rolling stock, combining adjustable motor protection with robust electromechanical operation.
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2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...