Siemens 3RT20271AL20 AC Contactors
Parameter Comparison — S0 Frame, 32 A AC-3 Contactors
| Parameter | 3RT20271AL20 (seed) | 3RT20271AL201AA0 | 3RT20271AL24 | 3RT20271AU20 | 3RT2027-1AM20 | 3RT20271AG20 | 3RT20271AC20 | 3RT20271AH20 |
|---|---|---|---|---|---|---|---|---|
| Coil Voltage | 230 VAC | 230 VAC | 230 VAC | 380 VAC | 208 VAC | 110 VAC | 24 VAC | 48 VAC |
| Contact Rating | 32 A | 32 A | 32 A | 32 A | 32 A | 32 A | 32 A | 32 A |
| Contact Form | 3PST-NO | 3PST-NO | 3PST-NO | 3PST-NO | 3PST-NO | 3PST-NO | 3PST-NO | 3PST-NO |
| Aux Contacts | 1NO/1NC | 1NO/1NC | 2NO/2NC | 1NO/1NC | 1NO+1NC | 1NO/1NC | 1NO/1NC | 1NO/1NC |
| Coil Power | 81 VA | 79 VA | 79 VA | 79 VA | 79 VA | 81 VA | 81 VA | 79 VA |
| Must Operate | 195.5 VAC | 195.5 VAC | 195.5 VAC | 323 VAC | 176.8 VAC | 93.5 VAC | 20.4 VAC | 40.8 VAC |
| Operate Time | 40 ms | 40 ms | 40 ms | 40 ms | 40 ms | 40 ms | 40 ms | 40 ms |
| Mounting | Chassis/DIN | Chassis/DIN | Chassis/DIN | Chassis/DIN | Chassis/DIN | Chassis/DIN | Chassis/DIN | Chassis/DIN |
| Encapsulation | Bulk | Box | Box | Box | Box | Bulk | Bulk | Box |
Coil voltage is the primary differentiator across this family group. Readers must verify that their control-circuit voltage matches the must-operate threshold before selection.
Why the Alternates Are Similar
The 3RT20271AL201AA0 shares the same 230 VAC coil and 1NO/1NC auxiliary configuration; the only distinction is packaging (box vs bulk). The 3RT20271AL24 and 3RT71AL243MA0 match on voltage and current but add a second auxiliary contact set (2NO/2NC), which may suit applications requiring dual signal or interlock paths. The remaining alternates diverge on coil voltage: 3RT20271AU20 at 380 VAC, 3RT2027-1AM20 at 208 VAC, 3RT20271AG20 at 110 VAC, 3RT20271AH20 at 48 VAC, and 3RT20271AC20 at 24 VAC—all retain the same 32 A main pole rating and chassis/DIN mounting.
Key Specifications — Siemens 3RT20271AL20
- Frame size: S0 (Siemens size 00–S3 classification, 45 mm width typical)
- Main poles: Three normally-open contacts rated 32 A AC-3 at 230–400 VAC
- Auxiliary contacts: One NO + one NC integrated
- Coil draw: 81 VA inrush; holding power determined by must-operate at 195.5 VAC
- Mechanical operate time: 40 ms
- Thermal current (Ith): 40 A per IEC 60947-4-1 for open-type devices
- Mechanical endurance: 30 million operating cycles (typical for this series)
- Terminals: Screw-type main and auxiliary terminals per IEC 60947
Engineering Verification Checklist
- Confirm control-circuit voltage is 230 VAC nominal; must-operate threshold 195.5 VAC allows 15% line dip before dropout
- Verify load current ≤ 32 A AC-3; derate for AC-1 or DC switching per Siemens derating curves if ambient exceeds 60°C
- Check auxiliary contact rating (1NO/1NC) suits the interface voltage and current requirements of the pilot circuit
- Confirm DIN rail or chassis mounting dimensions match the panel cutout and enclosure depth
- Validate that upstream short-circuit protection coordinate with the contactor's conditional short-circuit current rating (Icc ≤ 10 kA typical at 230 VAC)
- Verify the bulk packaging form factor fits the procurement and storage workflow