Skip to main content
Siemens 3RT1055-6AU36 — Contactors

Siemens 3RT1055-6AU36 SIRIUS Power Contactor, Size S6, 240-2

MPN3RT1055-6AU36
Active

Siemens SIRIUS 3RT1055-6AU36 power contactor, size S6, 240-277 V AC coil, screw-type terminals, 172 x 120 x 170 mm.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RT1055-6AU36 — Identification
ParameterValue
Contactor frame sizeS6
3RT1055-6AU36 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated operational current, AC-4 @ 400 V132 A
Rated value @ 400 V3 A
Rated value @ 500 V2 A
Rated value @ 690 V1 A
Rated value @ 230 V30 hp
Rated value @ 24 V10 A
Rated value @ 60 V2 A
Rated value @ 110 V1 A
Rated value @ 220 V0.3 A
3RT1055-6AU36 — Control & Coil
ParameterValue
Control supply voltage typeAC/DC
Rated value @ 50 Hz0.8
Rated value @ 50 Hz240 ... 277 V
3RT1055-6AU36 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT1055-6AU36 — Protection & Coordination
ParameterValue
Short-circuit coordination type 1, fusegG: 355 A (690 V, 100 kA)
Short-circuit coordination type 2, fusegG: 315 A (690 V, 100 kA), aM: 200 A (690 V, 50 kA), BS88: 315 A (415 V, 50 kA)
Aux. switch short-circuit protection, fusegG: 10 A (500 V, 1 kA)
3RT1055-6AU36 — Connection & Mounting
ParameterValue
Main circuit connectionConnection bar
Aux. / control circuit connectionscrew-type terminals
Conductor cross-section, solid2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)
Conductor cross-section, solid or stranded2x (0,5 ... 1,5 mm²), 2x (0,75 ... 2,5 mm²), max. 2x (0,75 ... 4 mm²)
Conductor cross-section, finely stranded w/ ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Mounting methodscrew fixing
Side-by-side mountingYes
3RT1055-6AU36 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT1055-6AU36 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT1055-6AU36 — Mechanical
ParameterValue
Width120 mm
Height172 mm
Depth170 mm
3RT1055-6AU36 — Specifications
ParameterValue
At AC40 ... 60 ms

Product details

It's part of the SIRIUS modular contactor family, which means it integrates with the same SIRIUS accessory ecosystem for overload relays, suppressors, and busbar systems. The contactor measures 172 mm high by 120 mm wide by 170 mm deep, and mounts via screw fixing to a vertical surface. It carries a 240-277 V AC coil, with a pickup threshold of 0.8 x rated voltage at both 50 Hz and 60 Hz, and a dropout threshold of 0.8 x rated voltage. The full-scale operating range extends to 1.1 x rated voltage, so it holds in on a stiff 277 V line without saturation issues.

That's a tight window for a contactor this size — it holds takt time on a weld line where every cycle is gated by the main contactor's dropout. The mechanical endurance is 10,000,000 operations typical, which translates to years of service at 750 cycles/hour under AC-3 duty. Switching frequency varies by duty class: 800 cycles/hour at AC-1 (resistive), 750 cycles/hour at AC-3 (motor start/run), and 130 cycles/hour at AC-4 (plugging/inching). If your application involves frequent reversing or jogging, the AC-4 limit is the one that governs — exceeding it will overheat the arc chamber. The main power circuit accepts stranded conductors from 25 to 120 mm², which covers everything from a 35 mm² motor feed to a 95 mm² busbar tap. The auxiliary circuit uses screw-type terminals accepting 2x (0.5-1.5 mm²) solid or 2x (0.75-2.5 mm²) stranded, with a max of 2x (0.75-4 mm²). That's enough for two parallel 1.5 mm² control wires per terminal. The built-in auxiliary switch is rated 10 A at 24 V, 2 A at 48 V and 60 V, and 1 A at 110 V. Those are the current-carrying limits for the auxiliary contacts — don't use them to switch the coil of a downstream contactor without checking the inrush against these ratings.

Integration and Panel Layout

These are the minimum air gaps to adjacent metalwork or other devices — ignoring them can cause flashover during arc extinction. The mounting holes are 9 mm diameter, single hole per terminal, so use M8 bolts or studs.

Frequently asked questions

What is the closest functional alternative to 3RT1055-6AU36?

The 3RT1055-6LA06 is a direct peer within the same SIRIUS size S6 frame. The primary difference is the coil voltage — 6LA06 uses a 110 V AC coil versus the 240-277 V AC coil on the 6AU36. Panel cutouts and accessory compatibility are identical; the swap decision depends entirely on your control voltage.

What are the physical dimensions of 3RT1055-6AU36?

Height is 172 mm, width is 120 mm, and depth is 170 mm. The mounting hole diameter is 9 mm.

What wire sizes does the main power circuit accept?

The main terminals accept stranded conductors from 25 mm² up to 120 mm². The auxiliary terminals accept 2x (0.5-1.5 mm²) solid or 2x (0.75-2.5 mm²) stranded, with a maximum of 2x (0.75-4 mm²).

MPN
3RT1055-6AU36