Brand:

ABB TF42-10 Thermal Overload Relay 7.60-10.0 A

Description

TF42-10 covers 7.6 to 10 A, a common step for 4 kW motors

TF42-10 (1SAZ721201R1043) is set between 7.6 A and 10.0 A. It shares the upper limit of its range with the rated operational current AC-3, which the data sheet defines as the upper value of the setting range, so 10 A for this relay.

Many small industrial motors fall in this step, though the nameplate decides. The relay mounts on AF09 to AF38 contactors.

Technical specifications

Parameter Specification
Type designation / order code TF42-10 / 1SAZ721201R1043
Setting range 7.60 to 10.0 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 19.30 mohm / 1.1 W at the lower and 1.9 W at the upper setting value
Short-circuit protection (gG fuse) 35.0 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 0.75-4 mm2
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 0.130 kg / IP20
Approvals (as printed) cULus (UL 508), CB, CCC, GOST-R, ABS, RINA, DNV, Lloyd’s Register, CE

Characteristics

Resistance per pole is 19.30 mohm. Power loss is 1.1 W at the lower and 1.9 W at the upper setting. A 35 A gG fuse is the listed short-circuit protection.

The thermal elements are bimetal strips, one per pole, heated directly and indirectly by motor current. When they bend, the relay trips and the contacts change position. The relay protects itself during overload and is protected against single-phase running by its phase-loss sensitivity.

Using it in a starter

Combine the relay with an AF contactor for a direct-on-line starter and wire the N.C. contact 95-96 in series with the contactor coil. The N.O. contact 97-98 can feed a lamp or a PLC input that needs a trip signal.

ABB notes in the data sheet that the relay should be set to the motor rated current and not the tripping current. At 1.05 times the setting no trip occurs, and at 1.2 times the relay trips.

Documents and quotation

The linked file is the ABB TF42 thermal overload relay data sheet 2CDC106023D0201. Seven Star LLC supplies the TF42-10 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
  • PDF 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.

Frequently Asked Questions

What is the setting range of the TF42-10?
7.6 to 10.0 A.
What is the resistance per pole?
19.30 mohm.
Which contactors can it be mounted on?
AF09 to AF38.
What trip class is it?
Class 10.
Does it protect against phase loss?
Yes, the relay is phase-loss sensitive.