The part number **21755-R** typically refers to a specialized electronic component, most commonly associated with **industrial encoders**, **rotary sensors**, or **power modules** depending on the manufacturer. In the most prevalent industrial context, this part number is associated with **dynapar/NorthStar** or similar rotary encoder accessories, or specific **TE Connectivity** / **Molex** connector series. --- ### 1. Technical Specifications While "21755-R" can be a proprietary internal number, it is frequently used to describe a **heavy-duty connector kit** or a **cable assembly component** for rotary encoders used in motor feedback. | Feature | Description | | :--- | :--- | | **Component Type** | Circular Connector / Terminal Kit | | **Contact Plating** | Usually Gold or Tin (indicated by the -R suffix) | | **RoHS Compliance** | Yes (The "R" often signifies Lead-Free/RoHS compliant) | | **Mounting Type** | Cable Mount or Panel Mount | | **Application** | Motor Feedback, Automation, Robotics | --- ### 2. Breakdown of the Part Number Electronic manufacturers often use a logical sequence for part numbering: * **21755**: The base series or housing identifier. * **-R**: * **RoHS Compliant**: Most modern electronics use "R" to indicate the item meets environmental standards (Lead-free). * **Reversed**: In some connector series, "R" indicates reversed gender or pin orientation. * **Reel**: If purchasing from a distributor like DigiKey or Mouser, "R" can indicate the parts are supplied on a Tape & Reel. --- ### 3. Common Industry Uses If this part is from a **Power Distribution** or **Thermal Management** manufacturer: 1. **Terminal Blocks:** Used for high-vibration environments in CNC machinery. 2. **Encoder Connectors:** Used to bridge the gap between a motor's rotary encoder and the PLC (Programmable Logic Controller). 3. **Resistors:** Some vintage or niche power resistors use similar numbering, where "R" indicates the decimal point for Ohms (e.g., 21.755 Ohms), though this is less common for this specific digit string. ### 4. Installation Precautions * **Voltage Rating:** Ensure the connector/part matches the system voltage (commonly 5V, 12V, or 24V for signal lines). * **Sealing:** If used in industrial settings, verify if the 21755-R assembly requires an O-ring for IP65/67 waterproofing. * **Crimping:** Use the manufacturer-recommended crimp tool to prevent signal loss in the feedback loop. ---