Siemens 3RT2036-1AN20 AC Contactor

The Siemens 3RT2036-1AN20 is a 3-pole AC contactor from the SIRIUS 3RT2 series, designed for switching motors and other loads in industrial automation systems. With a rated operational current of 50 A (AC-3 duty at 400V) and a coil voltage of 220-240V AC 50/60Hz, this contactor provides reliable control for motors up to 22 kW at 400V. It is suitable for use in control cabinets, motor control centers, and machinery panels.

Technical Specifications

The contactor features three main poles with silver-based contacts ensuring low contact resistance and high durability. The rated insulation voltage (Ui) is 1000V, and rated impulse withstand voltage (Uimp) is 8 kV. The AC-3 rated operational current is 50 A at 40°C ambient temperature. Breaking capacity for AC-3 duty is 8 times the rated current. The contactor also supports AC-1 resistive load switching up to 63 A. Short-circuit protection is provided by fuses or circuit breakers up to 160 A.

The coil operates at 220-240V AC, 50/60Hz with inrush power consumption of approximately 200 VA and holding power of 15 VA. Coil operating limits are 0.85 to 1.1 times the rated control voltage. The contactor includes an integrated surge suppressor (varistor) to reduce electromagnetic interference during coil de-energization. Auxiliary contacts are available as snap-on add-on blocks; the base unit includes one normally open and one normally closed auxiliary contact.

Key Features

• 3-pole main contacts, 50 A AC-3 rating (400V)

• Coil voltage 220-240V AC, 50/60Hz

• Motor power rating: 22 kW at 400V AC-3

• Built-in surge suppressor (varistor)

• Screw terminals for main and auxiliary circuits

• Snap-on auxiliary contact blocks (expandable)

• Din rail or screw mounting

• Operating temperature -25 to +60°C

• Mechanical life: 10 million operations

• Electrical life: 1.2 million operations (AC-3)

Construction and Installation

The 3RT2036-1AN20 features a compact design with width 55mm, height 85mm, and depth 97mm. Terminals are finger-safe according to EN 50274. Main terminal capacity accommodates solid or stranded conductors up to 25 mm² (AWG 4). The coil terminals accept up to 4 mm² conductors. The contactor mounts on standard 35mm DIN rail (EN 60715) or with M4 screws for panel mounting. Auxiliary contact blocks (e.g., 3RH2911-1HA11) snap onto the front without tools, providing up to 4 additional contacts.

Applications

This contactor is commonly used for starting and stopping three-phase induction motors in pumps, fans, compressors, conveyors, and machine tools. It also serves as a switching device for resistive heating loads, lighting circuits, and power supplies. In motor control centers, it pairs with overload relays (e.g., 3RU2136) to form a motor starter. The contactor is suitable for both direct-on-line (DOL) star-delta starting and reversing applications.

Standards and Certifications

The 3RT2036-1AN20 complies with IEC 60947-4-1, EN 60947-4-1, and UL 60947-4-1 (CSA C22.2 No. 60947-4-1). It carries CE, CCC, EAC, and UKCA markings. The contactor meets environmental standards RoHS and REACH. Flammability rating according to UL94 V-0 (housing material).

Maintenance and Life Expectancy

Electrical life under AC-3 duty is 1.2 million operations, while mechanical life reaches 10 million operations under no-load conditions. No routine maintenance is required beyond periodic inspection of contact wear and terminal tightness. Contactors in dusty environments may benefit from occasional cleaning. Siemens recommends replacement when contact erosion exceeds 2mm or after reaching rated electrical life.

Conclusion

The Siemens 3RT2036-1AN20 AC contactor delivers robust and reliable switching for industrial motor control. Its SIRIUS design ensures high performance, long service life, and easy integration into control systems. For applications requiring 50A switching capability with 220-240V AC coils, this contactor is a proven solution.