The Siemens 3RT2028-1AP00 is a SIRIUS 3RT2 power contactor in size S0 that switches three-phase motors up to 18.5 kW at 400 V (38 A in utilisation category AC-3), with a 230 V AC, 50 Hz operating coil. It has 1 NO + 1 NC integrated auxiliary contacts, and Siemens rates it at 50 A for resistive (AC-1) loads at 40 °C. Per the Siemens data sheet the coil picks up within 8 … 40 ms and drops out within 4 … 16 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 | 3RT2028-1AP00 |
|---|---|
| Product | SIRIUS 3RT2 power contactor, 3-pole |
| Size | S0 |
| Utilisation category | AC-3 / AC-3e |
| Rated operational current AC-3 at 400 V | 38 A |
| Motor power AC-3 at 400 V | 18.5 kW |
| Motor power AC-3 at 230 V | 11 kW |
| Operational current AC-1 (40 °C, up to 690 V) | 50 A |
| Rated operating voltage, max. | 690 V |
| Coil voltage | 230 V AC, 50 Hz |
| Coil operating range | 0.8 … 1.1 x Us (50 Hz) |
| Coil pick-up power (50 Hz) | 77 V·A |
| Coil holding power (50 Hz) | 9.8 V·A |
| Auxiliary contacts (integrated) | 1 NO + 1 NC |
| Closing delay | 8 … 40 ms |
| Opening delay | 4 … 16 ms |
| Mechanical service life, typ. | 10,000,000 operating cycles |
| Power loss per pole (rated current) | 3.2 W |
| Short-circuit protection, main circuit (type 1) | gG: 125 A (690 V,100 kA), aM: 50 A (690 V,100 kA), BS88: 125 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) | 45 x 85 x 97 mm |
| Net weight | 0.398 kg |
| Condition | New, original Siemens |
Typical applications
- Star-delta starter assemblies
- Conveyor, mixer and packaging machine drives
- 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 S0 directly under the contactor, or combine it with a 3RV2 motor starter protector of the same size using the Siemens link module. Auxiliary contact blocks (3RH2911) can be snapped on the front to add more NO/NC contacts.
Frequently asked questions
What coil voltage does it need?
Per Siemens: 230 V AC, 50 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.
How fast can you deliver, and is there a warranty?
Air shipping usually takes 5 to 7 days once the part is ready, to almost any country. Each part is new and original with a 1-year warranty. Message us on WhatsApp with the order number for a quotation.
Ordering tips
Send us the full order number from the label of the old part, or a clear photo of the label, together with the quantity you need. We check the number against the current manufacturer data before we quote and tell you if there is a newer replacement.
Need it fast? Send the order number, quantity and delivery country on WhatsApp or through the inquiry form and we reply with a quotation the same working day. All parts are new and original, covered by a 1-year warranty, and ship worldwide by air in 5 to 7 days once ready (shipping, payment and warranty). Local agents: Saudi Arabia, Iraq, the UAE, Egypt, Oman, Libya, Morocco, Mauritania, Yemen, Algeria and Jordan.
