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Brand: ABB
ABB TF42-24 Thermal Overload Relay 20.0-24.0 A
Description
TF42-24: an overload relay for 20 to 24 A motor currents
TF42-24 (1SAZ721201R1051) is the TF42 relay for 20.0 to 24.0 A. Its main terminals follow the ABB group for relays above 20 A, which accept 1.5 to 2.5 mm2 or 2.5 to 10 mm2 conductors in solid or stranded form.
It is selected where the nameplate current lies in this band, and mounts directly under the larger AF contactors of the AF09 to AF38 series.
Technical specifications
| Parameter | Specification |
|---|---|
| Type designation / order code | TF42-24 / 1SAZ721201R1051 |
| Setting range | 20.0 to 24.0 A (current setting scale in amperes) |
| Device type | Three-pole bimetallic thermal overload relay, trip class 10, phase-loss sensitive |
| Resistance / power loss per pole | 4.51 mohm / 1.8 W at the lower and 2.6 W at the upper setting value |
| Short-circuit protection (gG fuse) | 63.0 A gG |
| Rated voltage / frequency | Ue 690 V AC (600 V DC); 50/60 Hz; Ui 690 V; Uimp 6 kV |
| Auxiliary contacts | 1 N.C. (95-96) + 1 N.O. (97-98); N.C. 3 A at 230 V AC-15 |
| Reset / functions | Automatic or manual reset selectable; STOP and TEST buttons; status indication; trip-free mechanism |
| Terminal capacity (main circuit) | 1/2 x 1.5-2.5 mm2 or 1/2 x 2.5-10 mm2 (above 20 A) |
| Mounting | Direct on AF09 to AF38 contactors; or on a 35 mm DIN rail with a single mounting kit |
| Ambient temperature | Operation -25 to +60 C, temperature compensated; storage -50 to +80 C |
| Weight / protection | 0.145 kg / IP20 |
| Approvals (as printed) | cULus (UL 508), CB, CCC, GOST-R, ABS, RINA, DNV, Lloyd’s Register, CE |
Technical points
Resistance per pole is 4.51 mohm, with 1.8 W loss at the lower and 2.6 W at the upper setting. The short-circuit protective device is a 63 A gG fuse, as for the TF42-20.
The tightening torque for the main terminals is 2.5 to 2.7 Nm for this group, against 1.5 to 2.5 Nm for the smaller relays; follow the value from the data sheet when wiring.
Testing and signalling
Use the TEST button to confirm the circuit before commissioning. In auto reset mode the contacts return after the bimetal cools; in manual reset mode the RESET button must be pressed.
The status indicator shows the relay state, and the sealable operating elements allow the setting to be locked. The N.O. contact 97-98 supports a separate trip alarm.
Documents and quotation
The linked file is the ABB TF42 thermal overload relay data sheet 2CDC106023D0201. Seven Star LLC supplies the TF42-24 on request from Muscat as an independent supplier; availability and lead time are given in the quotation. More products of this kind are in the Contactors & Overload Relays category, and a related item is the ABB AF09-30-10-11 contactor.
The data sheet is a general one for all TF42 steps, so the values on this page are those of the exact type shown in its tables. Confirm before ordering: the motor nameplate full-load current (the relay is set to it), the contactor type it will be mounted on, the short-circuit protection ahead of it and whether manual or automatic reset is wanted.
Datasheets & Documents
- Datasheet ABB TF42 thermal overload relay data sheet 2CDC106023D0201 Download
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About brand
ABB is the Swiss-Swedish engineering group for electrification and automation: low voltage drives, motors, circuit breakers and motor control, process instruments and analysers, control systems and robots. It was formed on 5 January 1988 by the merger of two older companies. ASEA was founded in Västerås, Sweden, in 1883 by Ludvig Fredholm to make electric lighting and generators. BBC Brown Boveri was founded in Baden near Zurich in 1891 by Charles E. L. Brown and Walter Boveri. ABB Ltd is incorporated in Switzerland, headquartered in Zurich and listed on the SIX Swiss Exchange and Nasdaq Stockholm.
ABB company profile
| Formed | 5 January 1988, by the merger of ASEA (Sweden) and BBC Brown Boveri (Switzerland), each holding 50% |
|---|---|
| ASEA | Founded 1883 in Västerås, Sweden, by Ludvig Fredholm; first products electric lighting and generators |
| Brown, Boveri & Cie | Founded 1891 in Baden, Switzerland, by Charles E. L. Brown and Walter Boveri |
| Headquarters | Zurich, Switzerland; ABB Ltd became the group holding company in 1999 |
| Ownership | Public company listed on SIX Swiss Exchange and Nasdaq Stockholm |
| Brands in the group | Baldor (US motors, acquired 2011), B&R (machine automation, acquired 2017), K-TEK level instruments, Endura and Navigator analysers, SACE breakers |
| Product families | Low and medium voltage drives (ACS series), motors, SACE Tmax and Emax breakers, contactors and soft starters, flow, pressure, temperature and level instruments, liquid and gas analysers, Contrac actuators, AC500 PLCs, Ability System 800xA and S800 I/O, protection relays, robots |
Milestones
- 1883: ASEA is founded in Västerås, Sweden.
- 1891: Brown, Boveri & Cie is founded in Baden, Switzerland.
- 1987–1988: The merger is announced on 10 August 1987; ABB Asea Brown Boveri starts operating on 5 January 1988.
- 1999: ABB Ltd, incorporated in Switzerland, becomes the single holding company of the group.
- 2011 and 2017: Baldor Electric and B&R join ABB.
- 2020: ABB sells its power grids business to Hitachi, focusing on electrification, motion, process and machine automation.
Choosing an ABB drive
ABB's ACS drive codes are easy to read once you know the pattern. In ACS580-01-046A-4, "ACS580" is the drive family, "01" means a wall-mounted single drive, "046A" is the rated output current (about 46 A) and "-4" means a 380–480 V supply. The family is chosen by application: ACS355 for compact machinery, ACS310 for simple pumps and fans, ACS580 as the general-purpose drive, ACQ580 for water and wastewater with pump functions such as pipe fill and dry-run protection, and ACS880 for heavy industrial duty with direct torque control. Size the drive on the motor's full-load current, not only its kW rating, and allow derating for the high ambient temperatures common in Gulf electrical rooms.
Where ABB products are used
In Oman and the GCC, ABB drives and motors run pumps, fans and compressors in water and wastewater plants, district cooling, oil and gas and industry. ABB flowmeters, level instruments and analysers are used in water utilities, power and desalination plants and refineries, and SACE breakers protect switchboards in buildings and plants.
ABB products we list
| Family | Examples |
|---|---|
| AC drives | ACS580, ACS580-01-046A-4, ACQ580, ACS355, ACS310, ACS880-01, FEN-31 encoder module |
| Breakers, motor control and protection | SACE Tmax XT, XT3N 250, SACE Emax 2, AF09 contactor, PSR soft starter, REM615 relay |
| Flow measurement | ProcessMaster FEP300, AquaMaster4, CoriolisMaster FCB430, VortexMaster FSV430, SwirlMaster FSS430, OriMaster FPD500 |
| Pressure, temperature and level | 266DRH, 267CS multivariable, TTH300, K-TEK AT100, LMT200, MT5000 GWR, KM26 gauge |
| Analysers | Endura AZ20, AK100 hydrogen purity, Navigator AW641 silica, AW402 chlorine, AWT210 |
| Control systems and actuators | AC500, AC500-S, S800 AI810, AC 800F SA 811F, Contrac RSD50, Contrac RHD4000 |
Ordering ABB products: what we need
Send the full type code from the nameplate (for example ACS580-01-046A-4 or 266DSH...) and, for spare parts, the ABB ID number (such as 3BSE008508R1 or 1SBL176001R3010). For drives, add the motor power and current and any option codes (+...). For instruments, send the complete order code, which sets range, materials and approvals. Baldor motors are listed on their own brand page.
Facts checked against ABB company filings and published histories of ASEA and Brown, Boveri & Cie, October 2026.
Related products
Frequently Asked Questions
What is the setting range of the TF42-24?
20.0 to 24.0 A.
Which fuse is listed?
63 A gG.
What torque is used on the main terminals?
2.5 to 2.7 Nm for relays above 20 A.
What is the resistance per pole?
4.51 mohm.
What is the weight?
0.145 kg.
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