What type of device is this and what does it do?
It is an auxiliary contactor (contactor relay) used to switch control circuits. When the 24 V DC coil is energised, it changes the state of its auxiliary contacts to provide interlocking, signalling, or logic functions in a panel.
What contact configuration does it provide?
It provides 4 auxiliary contacts in total: 2 normally open (NO) and 2 normally closed (NC), with no changeover (CO) contacts.
What is the control coil voltage and type of supply?
The control supply is 24 V DC. It is designed for DC operation rather than AC on the coil.
Are any of the contacts time-delayed or mechanically linked for make-before-break operation?
No. The contacts are standard instantaneous auxiliary contacts with no delayed switching and no make-before-break function.
What is the typical utilisation rating for control-duty switching?
For AC-15 (control of electromagnetic loads), the operating current is rated up to 4 A at 230 V and 3 A at 400 V.
How is it mounted inside a control cabinet?
It supports screw mounting and snap-on mounting onto a 35 mm standard DIN rail (DIN EN 50022), making it suitable for common UK/EU panel layouts.
What type of terminals does it use?
It uses screw-type terminals for both the auxiliary contacts and the control (coil) circuit, which is commonly preferred for secure panel wiring.
What is the front protection rating?
The front protection rating is IP20, providing protection against finger contact with live parts from the front under typical panel conditions.
What are the approximate overall dimensions?
Approximate dimensions are 48 mm (height) × 45 mm (width) × 68 mm (depth). Allow additional space for wiring bend radius and terminal access.
Is it suitable for interlocking and status indication circuits?
Yes. With 2 NO and 2 NC contacts, it is commonly used for electrical interlocking, run/stop permissives, alarm signalling, and feedback indication in control systems.
What does the marking “22 E” refer to on this device type?
“22 E” identifies the switching element arrangement as 2 NO + 2 NC auxiliary contacts (often referenced as the contact set code for this auxiliary contactor family).
How can I confirm I am selecting the correct coil type for my panel?
Check your control circuit supply is 24 V DC and that the coil is intended for DC operation. If your control supply is AC or a different DC voltage, a different coil variant would be required.
What reliability or service-life indicators are available for planning maintenance intervals?
Typical indicators include a B10 value of 400,000 operations (at 0.3 × Ie) and a T1 value of 20 years for proof test interval/service life reference. Actual results depend on load type, switching frequency, and installation conditions.
What Siemens reference is commonly associated with this contact set in the 3TH2 range?
This contact set is commonly associated with Siemens auxiliary contactor variant 3TH2022-0BB4 (often referred to as Siemens 22E in contact set terms).