Siemens Contactor, 3-pole, size 14, 335kW, 400/380V Part number 3TF6844-0CM7

Product Overview

The Siemens 3TF6844-0CM7 is a heavy-duty 3-pole power contactor from the SIRIUS 3TF6 / 3TF range (contactor size 14). It is designed for high-power motor and load switching, offering robust performance for industrial applications requiring high current and high switching capacity. With strong main contacts and multiple auxiliary contacts, this contactor is suitable for heavy AC motors, large three-phase loads, or systems requiring frequent switching under demanding conditions.

Key Features

• 3-pole main contacts — for three-phase motor or heavy load switching
• Main contact rating: up to 630 A at 400 V (AC-3) — suitable for heavy-duty applications
• Main contact capacity: up to 335 kW at 400 V (AC-3) — high-power motor compatibility
• Auxiliary contacts: 4 NO + 4 NC — for signalling, interlocking or control logic integration
• Vacuum-type contactor design (3TF6 series) — ensures reliable switching performance and extended contact life
• Screw-terminal connections for both main and auxiliary circuits — secure wiring, suitable for large conductors
• Insulation voltage rating: up to 1000 V (main circuit), 690 V (auxiliary circuit) — supports high-voltage environments
• Surge voltage and impulse resistance: up to 8 kV (main circuit) / 6 kV (auxiliary circuit) — robust against transients

Technical Specifications

• Article Number: 3TF6844-0CM7
• Series / Type: SIRIUS 3TF6, size 14
• Main Poles: 3 (three-phase main contacts)
• Main Contact Rating (AC-3, 400 V): 630 A
• Rated Motor Power (AC-3, 400 V): 335 kW
• Auxiliary Contacts: 4 Normally Open + 4 Normally Closed
• Insulation Voltage (Main Circuit): up to 1000 V
• Insulation Voltage (Auxiliary Circuit): up to 690 V
• Surge Voltage Resistance (Main / Aux): 8 kV / 6 kV
• Control Coil Supply: 200–240 V AC, 50/60 Hz (standard coil variant) — check coil variant when ordering
• Terminal Type: Screw-terminal for main and auxiliary circuits
• Mechanical Endurance: ~5 000 000 switching cycles
• Ambient Operating Temperature: –25 °C … +55 °C
• Protection Rating (housing / front): IP00 (requires enclosure to meet panel-protection ratings)

Applications

This contactor is suited for industrial motor control, heavy machinery switching, large compressor or pump starters, large HVAC systems, heavy-duty loads in manufacturing, and any application requiring high power switching. With multiple auxiliary contacts, it is also useful for control-logic integration, signalling, interlocking, and automation of complex systems. Ideal for motor control centers (MCCs), switchgear, industrial panels, and any environment where reliability and high current capacity are essential.