The **1490-RBU** is a specific electronic accessory manufactured by **Rockwell Automation (Allen-Bradley)**. It is categorized as a **Remote Reset Solenoid Unit**, primarily used in conjunction with industrial circuit breakers and thermal overload relays. --- ### 1. Function and Purpose The 1490-RBU is designed to allow operators to reset a tripped device (like a 1490 Series Circuit Breaker) from a distance. In industrial control panels, safety protocols often require the enclosure to remain closed while the equipment is live; this solenoid allows for electronic resetting via a pushbutton on the cabinet door or through a PLC (Programmable Logic Controller) signal. ### 2. Technical Specifications Below are the general characteristics typically associated with the 1490-RBU series: | Feature | Specification | | :--- | :--- | | **Component Type** | Remote Reset Solenoid / Unit | | **Compatibility** | Allen-Bradley 1490 series and specific Overload Relays | | **Voltage Options** | Often available in 24V DC, 120V AC, or 240V AC (Check specific suffix) | | **Duty Cycle** | Intermittent (designed for momentary activation) | | **Mounting** | Direct attachment to the front or side of the protection device | --- ### 3. Key Electronic Components The "parts" inside a 1490-RBU are relatively simple but robust for industrial environments: * **Electromagnetic Coil:** The heart of the unit. When energized, it creates a magnetic field that pulls a mechanical plunger. * **Plunger/Actuator:** A physical rod that moves when the coil is energized to strike the "Reset" button on the main circuit breaker. * **Terminal Blocks:** Secure connection points for the control wiring (typically A1/A2 or similar labeling). * **Housing:** High-impact, flame-retardant plastic designed to withstand high temperatures inside a control cabinet. --- ### 4. Application Example 1. **Fault Occurs:** A motor draws too much current, causing the 1490 circuit breaker to trip. 2. **Signal Sent:** An operator presses a "Reset" button on the HMI or control desk. 3. **Activation:** The 1490-RBU coil energizes, pushing the plunger. 4. **Recovery:** The circuit breaker is mechanically reset to the "On" or "Ready" position without the operator opening the high-voltage cabinet. --- ### 5. Installation Note > [!WARNING] > **Safety First:** Ensure all power is disconnected before installing or servicing a 1490-RBU. These units must be matched correctly to the control voltage of your system (e.g., do not apply 120V to a 24V DC rated solenoid).