Skip to main content
Siemens 3RT2027-2BF40 — Contactors

Siemens 3RT2027-2BF40 SIRIUS Power Contactor, 110 VAC Coil,

MPN3RT2027-2BF40
Active

Siemens SIRIUS power contactor, 3RT2027-2BF40, S0 frame size, 110 VAC coil, spring-type terminals, screw and snap-on 35 mm DIN rail mounting.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

3RT2027-2BF40 — Identification
ParameterValue
Contactor frame sizeS0
3RT2027-2BF40 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated operational current, AC-4 @ 400 V22 A
Rated value @ 400 V3 A
Rated value @ 500 V2 A
Rated value @ 690 V1 A
Rated value @ 230 V5 hp
Rated value @ 24 V10 A
Rated value @ 60 V2 A
Rated value @ 110 V1 A
Rated value @ 220 V0.3 A
3RT2027-2BF40 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RT2027-2BF40 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT2027-2BF40 — Protection & Coordination
ParameterValue
Short-circuit coordination type 1, fusegG: 125A (690V,100kA), aM: 50A (690V,100kA), BS88: 125A (415V,80kA)
Short-circuit coordination type 2, fusegG: 50A (690V,100kA), aM: 25A (690V, 100kA), BS88: 50A (415V, 80kA)
Aux. switch short-circuit protection, fusegG: 10 A (500 V, 1 kA)
3RT2027-2BF40 — Connection & Mounting
ParameterValue
Main circuit connectionspring-loaded terminals
Aux. / control circuit connectionspring-loaded terminals
Conductor cross-section, solid1 ... 10 mm²
Conductor cross-section, solid or stranded2x (0.5 ... 2.5 mm²)
Conductor cross-section, finely stranded w/ ferrule2x (0.5 ... 1.5 mm²)
Mounting methodscrew and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715
Side-by-side mountingYes
3RT2027-2BF40 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT2027-2BF40 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT2027-2BF40 — Mechanical
ParameterValue
Width45 mm
Height102 mm
Depth107 mm

Product details

It's a current-production part, so you're not hunting NOS or surplus for this one. The 110 VAC coil is rated at 0.8 times the rated value for pickup and 1.1 times for the full-scale value, meaning it'll pull in reliably on a sagging line but won't cook if the transformer runs a touch high. The spring-type terminals on the magnet coil and main contacts accept solid or stranded wire from 1 to 10 mm², or 2x (0.5 to 2.5 mm²) for daisy-chaining control wiring.

The S0 footprint is 45 mm wide, 102 mm tall, 107 mm deep — it'll fit a standard 8-inch deep enclosure with room for the gland plate. That's tight enough to pack contactors side-by-side in a multi-motor starter bucket without cooking each other.

Switching capability and life

Main contacts rated AC-1 at 18 A, AC-3 at 8 A — that's the motor-switching number that matters for a 5 hp, 230 V single-phase or a small three-phase motor. The 10 million mechanical operations typical life means it'll outlast the machine it's in, assuming you're not cycling it every 10 seconds. Switching frequency: 1,000 ops/hour at AC-1, 750 at AC-2 and AC-3, 250 at AC-4. If you're jogging or inching a load, stay under 250 cycles per hour or the arc chute will cook. Auxiliary switch is included, rated at 10 A at 24 V, 2 A at 48/60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. That covers most PLC input and relay coil loads without an interposing relay.

Environmental tolerance

That's fine for a non-condensing panel next to a hot motor or in an unheated warehouse. The arcing time is a tight 10 to 10 ms — consistent, which helps with contactor life on inductive loads. Pickup and dropout timing on DC is 15 to 18 ms — snappy enough for most sequencing, but if you're coordinating with a safety relay, account for that window in your timing budget.

Frequently asked questions

What are the key dimensions?

Width 45 mm, height 102 mm, depth 107 mm. Clearances: 10 mm up/down/forward, 6 mm sideways.

What wire sizes does the spring terminal accept?

Solid or stranded wire from 1 to 10 mm² for main contacts, and 2x (0.5 to 2.5 mm²) for daisy-chaining auxiliary wiring.

MPN
3RT2027-2BF40