The **MA28TCD-R** is a high-performance, ultra-compact brushless DC (BLDC) axial fan manufactured by **Nidec Copal Electronics**. It is specifically designed for high-reliability cooling in space-constrained electronic environments. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Input Voltage** | 5V DC (Range: 4.5V ~ 5.5V) | | **Dimensions** | 28mm x 28mm x 10mm | | **Bearing Type** | Sleeve Bearing / Long-life hybrid | | **Airflow Rate** | Approx. 0.045 m³/min (1.59 CFM) | | **Static Pressure** | 30 Pa | | **Rated Current** | 100 mA | | **Noise Level** | 21 dB (A) | --- ### 2. Internal Electronic Components The "R" suffix in the part number typically denotes a specific sensor output or rotation monitoring feature. The internal circuitry consists of several critical stages: #### A. The Brushless Controller IC Unlike brushed motors, the MA28TCD-R uses an integrated circuit (IC) to handle **Electronic Commutation**. This IC: * Senses the rotor position (usually via an internal Hall Effect sensor). * Sequentially energizes the stator coils to maintain rotation. * Eliminates physical brushes, significantly increasing the lifespan and reducing EMI (Electromagnetic Interference). #### B. Rotation Detector (R-Type Signal) The **-R** designation indicates a **Rotation Detector** or "Lock Signal" function: * **Function:** It monitors whether the fan is spinning or stalled. * **Output:** Typically an Open Collector output. When the fan is rotating, the signal is "Low"; if the fan stops (stalls), the signal goes "High." * **Protection:** This allows the host system to trigger an alarm or shut down components to prevent overheating if the fan fails. #### C. Protection Circuitry * **Auto-Restart:** If the fan blades are physically obstructed, the internal drive IC cuts power to the coils to prevent burnout. Once the obstruction is removed, the IC attempts to restart the motor automatically. * **Reverse Polarity Protection:** Prevents damage if the positive and negative leads are accidentally swapped during installation. --- ### 3. Wiring Diagram Pinout Most MA28TCD-R units utilize a 3-wire interface: | Wire Color | Function | Description | | :--- | :--- | :--- | | **Red** | VCC | Positive Power Supply (+5V) | | **Black** | GND | Ground (0V) | | **White/Yellow** | RD Signal | Rotation Detection (The "R" function) | --- ### 4. Typical Applications Due to its 28mm size and low noise profile, it is commonly found in: * **Portable Medical Devices:** CPAP machines or handheld diagnostic tools. * **Projectors:** Cooling internal lamp/LED drivers. * **Networking Gear:** Small routers, switches, and SFP modules. * **Embedded Systems:** Single-board computers (SBCs) and industrial controllers.