Schneider Electric LC1D170M7C AC Contactor – TeSys D Series

Schneider Electric LC1D170M7C — 170A TeSys D AC Contactor in Motor Control Architecture

The LC1D170M7C occupies the upper boundary of the TeSys D contactor platform, rated at 170A under AC-3 duty and engineered to switch three-phase induction motors up to 90 kW at 400V or 132 kW at 690V. Within a motor control center (MCC) or standalone starter panel, this device functions as the primary power-switching element in the control loop: it receives a discrete command signal from a PLC output or relay, energizes its 220V AC (M7) coil, and closes the main power contacts within a defined operate time — typically under 20 ms — to connect the motor to the supply bus. The same coil de-energizes on command or on protective trip, opening the contacts and isolating the load. This deterministic open/close cycle is the foundation of every motor start, stop, reversing, and star-delta sequence in industrial automation.

Unlike smaller contactors in the TeSys D range (LC1D09 through LC1D115), the LC1D170M7C uses a reinforced contact bridge assembly with silver-cadmium oxide (AgCdO) or silver-tin oxide (AgSnO₂) contact tips — materials selected for their arc-erosion resistance under high-current interruption. At 170A AC-3, each switching event generates a transient arc that must be extinguished within the arc chute before the next half-cycle. The contact geometry and arc runner design in this frame are optimized for that energy level, contributing to the rated 1,000,000 electrical operations at AC-3 and 10,000,000 mechanical operations over the device lifetime.

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Technical Parameters

Hardware Logical Analysis

The LC1D170M7C is built on a laminated electromagnetic core with a shading ring on the stationary pole face. The shading ring — a short-circuited copper band — phase-shifts a portion of the AC flux by approximately 90°, ensuring that the net magnetic force never passes through zero during each supply cycle. Without this mechanism, the armature would chatter at twice the supply frequency (100 Hz on 50 Hz systems), generating acoustic noise and accelerating contact wear. At 170A frame size, the shading ring cross-section is proportionally larger than in smaller TeSys D frames to sustain adequate holding force against the increased contact spring pressure required for high-current seating.

The main contact assembly uses a double-break configuration per pole. Each pole has two contact gaps in series, which halves the arc voltage per gap and reduces the energy that must be dissipated in each arc chute. This is particularly significant at 170A AC-3, where the prospective arc energy during interruption of a motor load (with its lagging power factor) is substantially higher than for resistive loads. The arc chutes are constructed from de-ionizing ceramic plates that split and cool the arc column, forcing rapid extinction before the next current zero crossing.

EMC performance is addressed at the coil circuit level. The coil generates a transient voltage spike on de-energization (L·di/dt) that can couple into adjacent signal wiring. Schneider Electric offers dedicated surge suppressor modules — LAD4RCU (RC network) and LAD4RCE (varistor) — that mount directly onto the coil terminals and clamp this transient to safe levels. For installations where the LC1D170M7C coil is driven by a PLC transistor output, the varistor type is preferred because it limits peak voltage more tightly than an RC network, protecting the output transistor junction.

The auxiliary contact block (1 NO built-in) provides the feedback signal path back to the control system. Its contact rating is 10A at 690V AC, sufficient for direct wiring into a PLC digital input module or a relay logic rung. Additional auxiliary contact blocks from the LADN series can be front-mounted to expand the feedback and interlocking capability without increasing the panel footprint beyond the contactor’s own width.

System Integration Benefits

• Deterministic switching latency: Operate and release times both under 20 ms allow PLC ladder logic to sequence multi-contactor topologies (star-delta, reversing) with predictable inter-step timing, eliminating the need for extended software timers to compensate for mechanical scatter.
• Direct PLC interface without interposing relay: The 220V AC coil can be driven directly from a relay output module rated ≥ 200 VA inrush. For transistor outputs, a single interposing relay bridges the 24V DC PLC domain to the 220V AC coil circuit, keeping the control architecture clean and auditable.
• Modular accessory integration: The TeSys D platform supports front-mount auxiliary blocks (LADN series), top-mount timer blocks (LADR series), and direct-mount overload relays (LRD3369 for 132–220A range), all without additional wiring harnesses. This reduces panel assembly time and eliminates potential wiring errors at accessory terminals.
• Diagnostic transparency via auxiliary contacts: The built-in 1 NO auxiliary contact, wired to a PLC input, provides real-time contactor state feedback. Discrepancy logic in the PLC program — comparing the commanded state to the feedback state — can detect welded contacts or coil failure within one scan cycle, enabling predictive maintenance alerts before a process fault occurs.
• Star-delta starter compatibility: Three LC1D170M7C units (main, star, delta) form a complete star-delta starter for motors up to 90 kW at 400V. The LAD9R1 mechanical interlock kit prevents simultaneous closure of the star and delta contactors, providing a hardware-level safety barrier independent of PLC software.
• Reversing starter architecture: Two LC1D170M7C units with a LAD9R1 reversing interlock kit implement a full reversing starter. The mechanical interlock ensures that only one contactor can be closed at any time, preventing phase-to-phase short circuits that would otherwise result from simultaneous closure.
• Thermal coordination with LRD overload relays: The LRD3369 overload relay (132–220A range) mounts directly onto the LC1D170M7C without a separate adapter, forming a thermally coordinated starter assembly. The bimetal trip characteristic of the LRD is matched to the thermal withstand curve of the contactor contacts, ensuring that the overload relay trips before the contacts reach their thermal damage threshold.
• Global certification acceptance: IEC/EN 60947-4-1, UL 508, and CSA C22.2 No. 14 certifications are recognized by engineering approval bodies in Europe, North America, and most export markets. Specifying the LC1D170M7C eliminates the need for project-specific re-certification of the starter assembly, reducing engineering overhead on international projects.

Quality Assurance & Global Logistics

Every LC1D170M7C unit supplied through siemensplc.com is sourced as genuine Schneider Electric product. Units are inspected upon receipt for original factory packaging integrity, holographic label authenticity, and date-code consistency. Where available, CE Declaration of Conformity documentation and factory test reports are retained and can be provided on request for project documentation packages.

Dispatch is handled from our warehouse in Xiamen, China — a major port city with direct access to international freight lanes serving Europe, Southeast Asia, the Middle East, and the Americas. Standard in-stock orders are processed within 1–2 business days. Express air freight options (DHL, FedEx, UPS) are available for urgent requirements, with transit times of 3–7 business days to most destinations. Sea freight consolidation is available for bulk orders where lead time permits. All shipments include commercial invoice, packing list, and country-of-origin documentation to support customs clearance. Import duties and local taxes are the responsibility of the consignee unless otherwise agreed in writing.

A 12-month warranty covers manufacturing defects from the date of dispatch. Warranty claims are processed by return shipment inspection; confirmed defective units are replaced or credited at our discretion. Units showing evidence of installation damage, overvoltage, or unauthorized modification are excluded from warranty coverage.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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