3TF48 PDF – AC Contactor, Siemens

Part Number: 3TF48

Function: AC Contactor

Manufacturer: Siemens

Images:3TF48 pdf datasheet


An AC contactor is an electrical switching device designed to control the flow of alternating current (AC) power in an electrical circuit. It is commonly used in industrial and commercial applications for controlling motors, lighting systems, heating elements, and other high-power AC loads.

The Siemens 3TF48 is a 3-phase IEC rated contactor used for the control of electric motors. It is rated 30 HP at 230V and 60 HP at 460V.


1. Construction: AC contactors consist of a set of contacts, an electromagnetic coil, and a mechanical mechanism for opening and closing the contacts. The contacts are typically made of high-conductivity materials like silver or copper to handle high current levels.

2. Operation: When the coil of an AC contactor is energized, it generates a magnetic field that pulls the contacts together, closing the circuit. This allows the AC power to flow through the contactor and supply the connected load. When the coil is de-energized, a spring or mechanical mechanism opens the contacts, interrupting the power flow.

3. Auxiliary Contacts: Many AC contactors feature additional auxiliary contacts that can be used for control signaling or interlocking purposes. These contacts are typically of lower current and voltage ratings compared to the main power contacts.

4. Control Methods: AC contactors can be controlled manually by an operator using a control switch or remotely through a control signal from a programmable logic controller (PLC), relay, or other control devices.

3TF48 pinout Contactor

AC contactors play a vital role in controlling high-power AC circuits in various industrial and commercial applications. They provide reliable and durable switching capabilities for managing motor loads, lighting systems, and other electrical equipment.

3TF48 PDF Datasheet