Rated 16 A / 7.5 kW at 400 V (AC-3), the Siemens 3RT2018-1BB42 is a 3-pole SIRIUS 3RT2 contactor, size S00, operated by a 24 V DC coil. It has 1 NC integrated auxiliary contact, and Siemens rates it at 22 A for resistive (AC-1) loads at 40 °C. Per the Siemens data sheet the coil picks up within 30 … 100 ms and drops out within 7 … 13 ms.
A contactor is the switching element of a motor starter: the PLC or a push-button energises the coil, and the main contacts connect the motor to the supply. Contactors wear with every start, so they are among the most frequently replaced parts in motor control centres.
See our Siemens industrial controls range, including SIRIUS 3RU2 overload relays and 3RV2 motor starter protectors for the same size.
Technical data
| Siemens order number | 3RT2018-1BB42 |
|---|---|
| Product | SIRIUS 3RT2 power contactor, 3-pole |
| Size | S00 |
| Utilisation category | AC-3 / AC-3e |
| Rated operational current AC-3 at 400 V | 16 A |
| Motor power AC-3 at 400 V | 7.5 kW |
| Motor power AC-3 at 230 V | 4 kW |
| Operational current AC-1 (40 °C, up to 690 V) | 22 A |
| Rated operating voltage, max. | 690 V |
| Coil voltage | 24 فولت DC |
| Coil operating range | 0.8 … 1.1 x Us |
| Coil pick-up power | 4W |
| Coil holding power | 4W |
| Auxiliary contacts (integrated) | 1 NC |
| Closing delay | 30 … 100 ms |
| Opening delay | 7 … 13 ms |
| Mechanical service life, typ. | 30,000,000 operating cycles |
| Power loss per pole (rated current) | 1W |
| Short-circuit protection, main circuit (type 1) | gG: 50 A (690 V, 100 kA), aM: 25 A (690 V, 100 kA), BS88: 50 A (415 V, 80 kA) |
| Ambient temperature (operation) | -25 … +60 °C |
| Connection type | screw-type terminals |
| Mounting | screw and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715 |
| Dimensions (W x H x D) | 45 x 58 x 73 mm |
| Net weight | 0.277 kg |
| Condition | New, original Siemens |
Typical applications
- Switching heaters and resistive loads (AC-1)
- Compact starter combinations with 3RV2 or 3RU2 in size S00
- Pump, fan and compressor control panels
- Replacement of a worn 3RT2 contactor with the same rating
Compatibility and replacement
For overload protection mount a SIRIUS 3RU2 thermal overload relay of size S00 directly under the contactor, or combine it with a 3RV2 motor starter protector of the same size using the Siemens link module. The coil voltage is coded in the order number (here 24 V DC), so check it against your control circuit before ordering.
Frequently asked questions
Is it suitable for a 7.5 kW motor at 400 V?
This contactor is rated 7.5 kW at 400 V (AC-3, 16 A). Choose a contactor whose AC-3 rating at your supply voltage is at least the motor rating.
Which overload relay fits it?
A SIRIUS 3RU2 overload relay of size S00, for example 3RU2116, set to the motor full-load current.
Do you ship to my country, and what is the warranty?
Yes. RendatSP ships worldwide from Yiwu, China, by air in 5 to 7 days once the part is ready, and every part carries a 1-year warranty. Send the order number and quantity on WhatsApp and we will reply with a quotation.
Before you order
Compare the complete order number on the old unit with this page, including the suffix: in most ranges the last characters set the coil voltage, current range or version. If the label is worn, send us a photo and we will identify the part.
Every part RendatSP supplies is new and original, carries a 1-year warranty and ships worldwide by air in 5 to 7 days once ready (shipping, payment and warranty). Send us the order number and quantity on WhatsApp or through the inquiry form and we will quote the same working day. Agents in Saudi Arabia, Iraq, the UAE, Egypt, Oman, Libya, Morocco, Mauritania, Yemen, Algeria and Jordan.
