Rated 38 A / 18.5 kW at 400 V (AC-3), the Siemens 3RT2028-1AL20 is a 3-pole SIRIUS 3RT2 contactor, size S0, operated by a 230 V AC, 50/60 Hz 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. At 230 V the AC-3 motor rating is 11 kW.
Contactors in pump, fan, conveyor and compressor panels may switch thousands of times a day, and contact wear is the usual reason for replacement. Keeping a spare of the same order number avoids long stoppages.
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 | 3RT2028-1AL20 |
|---|---|
| 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, 50/60 Hz |
| Coil operating range | 0.8 … 1.1 x Us (50 Hz) |
| Coil pick-up power (50 Hz) | 81 V·A |
| Coil holding power (50 Hz) | 10.5 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
- Switching heaters and resistive loads (AC-1)
- Conveyor, mixer and packaging machine drives
- Replacement of a worn 3RT2 contactor with the same rating
- Star-delta starter assemblies
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
Can I use it for a 7.5 kW motor?
This contactor is rated 18.5 kW at 400 V (AC-3, 38 A). Choose a contactor whose AC-3 rating at your supply voltage is at least the motor rating.
How many auxiliary contacts does it have?
It has 1 NO + 1 NC integrated; more can be added with 3RH2911 auxiliary switch blocks.
Can I get a price and delivery time?
Prices are quoted on request. Send the order number, quantity and delivery country on WhatsApp and we will reply with price and delivery time; air shipping is usually 5 to 7 days once ready, with a 1-year warranty.
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.
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.
