The **Allen-Bradley 1336-R** series refers to **Regenerative Braking Units** (also known as Brake Modules) designed to work with the 1336 family of Adjustable Frequency AC Drives. These units are critical for managing the excess energy generated when a motor decelerates faster than its natural coast-to-speed. --- ### 1. Key Internal Electronic Components The 1336-R units are power electronic devices that interface directly with the DC bus of an AC drive. | Component | Function | | :--- | :--- | | **IGBT Power Module** | The main switching element (Insulated Gate Bipolar Transistor) that controls the flow of regenerative energy. | | **DC Bus Terminals** | Points of connection (+ and -) to the VFD's internal DC bus to sense overvoltage. | | **Gate Driver Board** | Provides the isolation and electrical signal necessary to trigger the IGBTs based on voltage levels. | | **Control Logic Board** | Monitors the DC bus voltage; when it exceeds a threshold, it commands the IGBT to discharge energy into a resistor. | | **Status LEDs** | Diagnostic indicators (typically for Power, Fault, and Braking activity). | --- ### 2. Operating Principle When a motor acts as a generator (during braking), the DC bus voltage in the drive rises. The 1336-R monitors this: 1. **Sensing:** The control board detects if the DC bus exceeds a pre-set limit (e.g., 750VDC for a 460V system). 2. **Switching:** The logic fires the **IGBT**. 3. **Dissipation:** The excess energy is directed to an external **Dynamic Braking Resistor** where it is converted into heat. 4. **Protection:** If the IGBT overheats or the resistor thermal switch trips, the 1336-R sends a fault signal to the VFD to stop operation. --- ### 3. Specifications Table Most 1336-R units are categorized by their voltage class and duty cycle. | Specification | Typical Value | | :--- | :--- | | **Voltage Classes** | 230V, 460V, or 575V AC | | **Peak Current** | Varies by model (e.g., 30A to 120A+) | | **Interface** | Terminal blocks for DC+, DC-, and Thermal Interlock | | **Enclosure Type** | IP00 (Open) or IP20/NEMA 1 | --- ### 4. Wiring Diagram Overview (Simplified) ```text [ VFD DC BUS ] <------> [ 1336-R MODULE ] <------> [ BRAKING RESISTOR ] (+ / -) (IGBT Switch) (Heat Sink) ``` --- ### 5. Maintenance and Troubleshooting * **Check DC Bus Voltage:** Ensure the VFD and 1336-R are matched in voltage rating. * **Thermal Interlock:** Always wire the resistor's thermal switch back to the 1336-R or the VFD's "External Fault" input to prevent fires if the IGBT fails in a "closed" position. * **Capacitor Health:** Check for bulging or leaking capacitors on the internal control boards if the unit is older than 10 years.