Siemens 3RT20251AK60 | S0 Frame 3-Pole Contactor, 120 VAC Coil, 1NO/1NC
Overview
Installed in motor control centers, motor starter combinations, and power distribution enclosures, the Siemens 3RT20251AK60 is a Size S0 electromechanical contactor that provides three main power poles plus one auxiliary normally-open and one auxiliary normally-closed contact. The catalog record lists a 40 A contact rating and a 68 VA inrush coil consumption at 120 VAC; however, the AC3 power rating in kilowatts or horsepower—the primary motor coordination parameter—is absent from the supplied fields and must be confirmed from the official Siemens datasheet before selection.
Key Parameters
| Parameter | Value (from catalog) | Notes |
|---|---|---|
| Base Product Number | 3RT2025 | S0 frame family |
| Coil Voltage | 120 VAC | Must operate ≥ 96 VAC |
| Coil Power (inrush) | 68 VA | Compare against system transformer capacity |
| Contact Form | 3PST-NO (3 Form A) | Three normally-open power poles |
| Auxiliary Contacts | 1NO + 1NC | Fixed auxiliary block |
| Contact Rating (Current) | 40 A | Verify whether this is the AC1 or AC3 rating |
| Mounting | Chassis Mount, DIN Rail | 35 mm rail or direct panel mount |
| Operate Time | 38 ms | Pickup time; release time not provided |
| Operating Temperature | 25°C to 60°C | Verify thermal derating at elevated ambient |
⚠ Verification required before purchase: The AC3 power rating (kW/HP), maximum switching voltage, breaking capacity, mechanical/electrical endurance cycles, terminal type, release (dropout) time, dimensions, weight, and applicable certifications (UL, CE, CCC) are not present in the supplied fields. Selection for motor branch protection or coordination studies must not proceed until these are confirmed on the Siemens datasheet.
Ordering-Code / Family Context
The MPN prefix 3RT2025 follows Siemens standard contactor ordering logic: 3RT2 denotes the Size S0 (S00/S0) series, 025 indicates the current size/pole arrangement, 1A encodes the coil voltage class, and the trailing K60 specifies the auxiliary contact arrangement (1NO/1NC). This structure is consistent across the listed alternates. The primary MPN (3RT20251AK60) is distinguished by its fixed auxiliary contact configuration—other alternates in this family use 2NO/2NC or differ in coil voltage.
Integration / Installation Notes
The JSON confirms chassis-mount and DIN-rail (35 mm) mounting; however, cutout dimensions, IP degree of protection, terminal torque specifications, and recommended enclosure sizing are not provided. For new panel builds, confirm these mechanical parameters from the Siemens 3RT2 datasheet. For substitution, note that alternates with the same base product number share the same mounting footprint, but coil voltage and auxiliary contact arrangements differ—verify control-circuit wiring against the auxiliary contact form before replacing.
Selection and Substitution
Substitution across the listed alternates is viable only when coil voltage, contact arrangement, and contact rating are verified against the target application. The primary MPN offers a 120 VAC coil with 1NO/1NC auxiliary; alternates such as 3RT20251AK64 provide 2NO/2NC auxiliary contacts but with 17 A contact rating (versus the 40 A in the seed record—a discrepancy that warrants datasheet verification). Voltage-class variants (3RT20251AV60 at 480 VAC, 3RT20251AN60 at 220 VAC) share the S0 frame and DIN-mount form factor but alter the control-circuit transformer specification. No substitute should be assumed interchangeable without confirming the AC3 rating, coil voltage tolerance, and auxiliary contact configuration against the specific installation.
Similar Catalog Parts
| MPN | Coil Voltage | Contact Rating | Aux Config | Coil Power | Similarity |
|---|---|---|---|---|---|
| 3RT20251AK60 (primary) | 120 VAC | 40 A | 1NO/1NC | 68 VA | — |
| 3RT20251AK601AA0 | 120 VAC | 17 A | 1NO/1NC | 67 VA | 1.0 |
| 3RT20251AK64 | 120 VAC | 17 A | 2NO/2NC | 67 VA | 1.0 |
| 3RT20251AN60 | 220 VAC | 17 A | 1NO/1NC | 67 VA | 0.96 |
Why they are similar: All share the Siemens 3RT2025 base product number, 3PST-NO (3 Form A) main contact form, auxiliary contacts feature, DIN-rail/chassis mount, and 25°C–60°C operating temperature range. The highest-similarity alternates (3RT20251AK601AA0, 3RT20251AK64) also use 120 VAC coil operation. The 0.96 variants differ primarily in coil voltage class. Note that the contact rating in the seed record (40 A) is higher than that in the alternates (17 A); this may reflect different test conditions (AC1 vs. AC3) and must be verified on the datasheet.
FAQ
Q: What coil voltage does the 3RT20251AK60 require? A: The catalog specifies a 120 VAC coil with a must-operate voltage of 96 VAC. The datasheet should confirm the must-release voltage and allowable voltage tolerance band for the control circuit.
Q: Does the 3RT20251AK60 include a mechanical latch, and what is its electrical endurance? A: The supplied fields list "Features: Auxiliary Contacts" only. A mechanical latching option exists in the 3RT2 family but the primary MPN does not indicate it; confirm the exact aux contact arrangement and electrical endurance cycles (AC3 operations) from the datasheet.
Q: What is the maximum switching voltage for the main power poles of the 3RT20251AK60? A: The maximum switching voltage is not present in the supplied fields. The title shows a 120 VAC coil, but the main pole voltage rating (typically up to 690 VAC in this series) must be verified on the Siemens datasheet before applying to high-voltage motor circuits.