Rated 65 A / 30 kW at 400 V (AC-3), the Siemens 3RT2037-1AL20 is a 3-pole SIRIUS 3RT2 contactor, size S2, operated by a 230 V AC, 50/60 Hz coil. It has 1 NO + 1 NC integrated auxiliary contacts, and Siemens rates it at 80 A for resistive (AC-1) loads at 40 °C. Siemens quotes a typical mechanical life of 10,000,000 operating cycles for this contactor.
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 | 3RT2037-1AL20 |
|---|---|
| Product | SIRIUS 3RT2 power contactor, 3-pole |
| Size | S2 |
| Utilisation category | AC-3 / AC-3e |
| Rated operational current AC-3 at 400 V | 65 A |
| Motor power AC-3 at 400 V | 30 kW |
| Motor power AC-3 at 230 V | 18.5 kW |
| Operational current AC-1 (40 °C, up to 690 V) | 80 A |
| Rated operating voltage, max. | 690 V |
| Coil voltage | 230 V AC, 50/60 Hz |
| Coil operating range | 0.8 … 1.1 x Us (50 Hz) |
| Coil pick-up power (50 Hz) | 210 V·A |
| Coil holding power (50 Hz) | 17.2 V·A |
| Auxiliary contacts (integrated) | 1 NO + 1 NC |
| Closing delay | 10 … 80 ms |
| Opening delay | 10 … 18 ms |
| Mechanical service life, typ. | 10,000,000 operating cycles |
| Power loss per pole (rated current) | 3.8 W |
| Short-circuit protection, main circuit (type 1) | gG: 250 A (690 V, 100 kA), aM: 160 A (690 V, 100 kA), BS88: 200 A (415 V, 80 |
| 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) | 55 x 114 x 130 mm |
| Net weight | 0.954 kg |
| Condition | New, original Siemens |
Typical applications
- Replacement of a worn 3RT2 contactor with the same rating
- Switching heaters and resistive loads (AC-1)
- Star-delta starter assemblies
- Conveyor, mixer and packaging machine drives
Compatibility and replacement
For overload protection mount a SIRIUS 3RU2 thermal overload relay of size S2 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 230 V AC, 50/60 Hz), so check it against your control circuit before ordering.
Frequently asked questions
What coil voltage does it need?
Per Siemens: 230 V AC, 50/60 Hz, operating range 0.8 … 1.1 x Us (50 Hz).
How many auxiliary contacts does it have?
It has 1 NO + 1 NC integrated; more can be added with 3RH2911 auxiliary switch blocks.
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.
RendatSP ships from Yiwu, China, to factories worldwide; air delivery usually takes 5 to 7 days once the part is ready. The part is new and original with a 1-year warranty (shipping, payment and warranty). For a quotation, message us on WhatsApp with the order number and quantity. We also have agents in Saudi Arabia, Iraq, the UAE, Egypt, Oman, Libya, Morocco, Mauritania, Yemen, Algeria and Jordan.
