ABB MS450 1SAM450000R1004 Manual Motor Starter – MS450 Series

ABB MS450 1SAM450000R1004 — Dual-Function Motor Protection in a Single IEC-Rated Device

The ABB MS450 (catalog reference 1SAM450000R1004) is a frame-size manual motor starter and circuit breaker designed to deliver simultaneous overload and short-circuit protection for three-phase AC motors in industrial control panels. Unlike a conventional thermal relay paired with a separate MCCB, the MS450 consolidates both protection functions into a single DIN-rail-mountable enclosure, reducing panel footprint, wiring complexity, and the number of potential failure points in the protection chain.

Within a motor control loop, the MS450 occupies the position immediately upstream of the motor contactor. It acts as the first line of defense against sustained overload currents — which cause winding insulation degradation over time — and as a fast-acting interrupting device against short-circuit fault currents that can destroy motor windings and bus conductors within milliseconds. The bimetallic thermal element responds to I²t heating, while the magnetic trip mechanism operates independently of thermal state, ensuring protection integrity even during cold-start fault conditions.

The current setting range is adjusted via a front-panel rotary dial, allowing commissioning engineers to calibrate the overload threshold directly to the motor’s full-load ampere (FLA) rating without removing the device from the panel. This tool-free adjustment eliminates the need for shunt resistor swaps or DIP switch reconfiguration common in older protection relay designs.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

Thermal Bimetallic Trip Mechanism: The MS450 employs a three-phase bimetallic strip assembly where each phase conductor passes through a calibrated heating element bonded to a bimetal strip. Under sustained overload, differential thermal expansion deflects the strip, mechanically releasing the trip latch. The deflection threshold is factory-calibrated to IEC Class 10A characteristics, meaning the device trips within 2 seconds at 7.2× the set current (cold state) and within 10 seconds at 7.2× the set current (hot state). This thermal memory behavior prevents nuisance tripping on motor inrush while maintaining protection against sustained overloads that would otherwise degrade winding insulation class.

Electromagnetic Instantaneous Trip: A separate magnetic solenoid actuator monitors peak current independently of the thermal element. When fault current exceeds the instantaneous trip threshold — typically 12× to 14× the maximum current setting — the solenoid armature displaces within sub-millisecond response time, mechanically decoupling the contact bridge before the fault arc can sustain. This dual-element architecture ensures that the thermal element handles slow-developing overloads while the magnetic element handles high-energy fault events, preventing the two protection modes from interfering with each other’s calibration.

EMC Design Considerations: The MS450 contact bridge uses silver-alloy contacts with arc-quenching chambers designed to suppress the high-frequency transients generated during contact separation under inductive load. These transients, if uncontrolled, can couple into adjacent signal wiring and corrupt encoder feedback or fieldbus communication. The arc chamber geometry forces the arc into a series of splitter plates, rapidly increasing arc voltage and extinguishing the arc within the first current zero crossing. This design is consistent with IEC 60947-2 arc interruption requirements and contributes to the device’s EMC compatibility in mixed-signal panels.

Phase-Loss Sensitivity: The three-phase bimetallic assembly provides inherent phase-loss detection. When one phase is lost, the remaining two phases carry increased current to maintain motor torque, causing asymmetric heating across the three bimetal strips. The unbalanced deflection pattern trips the device faster than a single-phase overload at the same aggregate current level, providing motor protection against the winding damage caused by negative-sequence currents during phase-loss conditions.

Manual Reset Logic: After a thermal trip, the bimetal strips must cool before the reset button becomes mechanically operable. This enforced cooling delay — typically 2 to 3 minutes — prevents immediate re-energization of a motor that has already experienced thermal stress, protecting both the motor winding and the downstream process from repeated fault cycling.

System Integration Benefits

• Reduced Panel BOM Complexity: Combining overload relay and circuit breaker functions into a single device eliminates the need for a separate thermal relay, reducing the number of terminal connections, DIN rail space, and inter-device wiring by approximately 40% compared to a relay-plus-MCCB topology.
• Deterministic Protection Response: The magnetic instantaneous trip operates independently of control voltage, PLC scan cycle, or fieldbus latency. Protection actuation is purely hardware-driven, ensuring sub-millisecond fault isolation regardless of the state of the automation layer above it.
• Direct ABB Contactor Compatibility: The MS450 is mechanically and electrically coordinated with ABB A-line contactors (A9 through A110 frame sizes), enabling Type 2 coordination per IEC 60947-4-1 when used in verified combinations. Type 2 coordination means neither the starter nor the contactor sustains damage after a short-circuit event, reducing post-fault replacement costs.
• Auxiliary Contact Expansion: The MS450-AX auxiliary contact block mounts directly onto the device body without additional wiring, providing normally-open and normally-closed status signals for PLC digital input modules. This enables the control system to log trip events, generate maintenance alerts, and implement motor protection interlocks without external current monitoring relays.
• Signaling Contact for Remote Indication: The MS450-CK signaling contact provides a dedicated trip-status output isolated from the main auxiliary contact, allowing simultaneous local panel indication and remote SCADA alarm without contact sharing or relay multiplication.
• Tool-Free Current Calibration: The front-panel rotary dial allows current setting adjustment from the panel face without de-energizing adjacent circuits or removing the device from the DIN rail. This reduces commissioning time and eliminates the risk of incorrect shunt resistor installation common in older relay designs.
• Wide Ambient Temperature Range: Rated operation from -25 °C to +60 °C covers outdoor enclosure installations in both arctic and tropical climates without derating, eliminating the need for panel heating or cooling accessories in most industrial environments.
• IEC and UL Dual Certification: The MS450 carries both IEC 60947 and UL 508 listings, allowing the same device to be used in panels destined for European, North American, and export markets without substitution, simplifying global machine builder procurement and spare parts management.

Quality Assurance & Global Logistics

Every ABB MS450 1SAM450000R1004 unit supplied by siemensplc.com is sourced through verified ABB distribution channels with full traceability documentation. Before dispatch from our Xiamen, China facility, each unit undergoes a four-stage verification protocol: supply chain documentation review, label and hologram authenticity check against ABB factory standards, mechanical operation test of the trip and reset mechanism, and packaging integrity inspection. Units that do not pass all four stages are quarantined and returned to the supply chain — they are never shipped to customers.

Xiamen’s position as a major southern China logistics hub provides direct access to DHL Express, FedEx International Priority, UPS Worldwide Express, and consolidated sea freight services. In-stock orders are processed and handed to the carrier within 1 to 3 business days. For time-critical projects, same-day dispatch is available on confirmed orders received before 14:00 CST. Export documentation — including commercial invoice, packing list, certificate of origin, and HS code declaration (HS 8536.49) — is prepared as standard for all international shipments. Multi-currency invoicing in USD, EUR, HKD, and CNY is supported. All electronic components are packed in anti-static, moisture-proof packaging with foam cushioning to prevent transit damage.

A 12-month warranty from the date of shipment covers manufacturing defects. Warranty claims are processed with a replacement-first policy: a replacement unit is dispatched upon receipt of the defective item, minimizing production downtime for the customer.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.