The **M2MS-B-R/UL** is a high-performance industrial manual motor starter (often referred to as a Motor Protection Circuit Breaker) manufactured by **Altech Corp**. It is designed to provide control and protection for electric motors by combining manual switching, short-circuit protection, and thermal overload protection into a single unit. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Manufacturer** | Altech Corp | | **Series** | M Series (M2MS) | | **Trip Type** | Thermal-Magnetic | | **Adjustment Range** | Varies by sub-model (typically 0.1A to 32A) | | **Voltage Rating** | Up to 600V AC | | **Phase** | 3-Phase (can be used for 1-phase) | | **Certifications** | UL 508, CSA, CE | | **Mounting** | 35mm DIN Rail | --- ### 2. Core Electronic and Mechanical Components The device functions through three primary internal mechanisms that work together to protect the motor: #### A. Thermal Overload Protection (Bimetallic Strip) * **Function:** Protects the motor from sustained overcurrent (overloading). * **Mechanism:** It contains a bimetallic element that heats up and bends at a rate proportional to the current flow. If the current exceeds the set dial value for too long, the strip trips the mechanism. * **Adjustability:** Features a front-facing dial to set the exact Full Load Amps (FLA) of the motor. #### B. Magnetic Short-Circuit Protection * **Function:** Protects the system from instantaneous high-current faults (short circuits). * **Mechanism:** An electromagnetic coil triggers an instantaneous trip if it detects a massive current spike (usually 10-15 times the rated current). #### C. Phase Failure Sensitivity * **Function:** Protects 3-phase motors if one phase is lost (single-phasing). * **Mechanism:** The internal linkage is designed to trip faster if the current becomes unbalanced across the three poles, preventing the motor from overheating and burning out. --- ### 3. Physical Interface and Connectivity * **Rotary Handle:** The "R" in the part number often denotes the **Rotary** style operator. This provides a clear visual indication of whether the device is ON, OFF, or TRIPPED. * **Screw Terminals:** Robust IP20 finger-safe terminals for secure wiring of power leads. * **Auxiliary Contacts (Optional Add-ons):** The side or front of the unit allows for the attachment of auxiliary switches to signal the motor status (Running/Fault) to a PLC or indicator light. --- ### 4. Why use the "UL" Version? The **/UL** suffix indicates that the part is specifically tested and listed under **UL 508** (Industrial Control Equipment). This is critical for North American panel builders to ensure compliance with NEC (National Electrical Code) standards for "Group Installation" or as a "Manual Motor Controller." ---