Technical Review: Siemens 3RU61161DB1 Overload Relay - Selection Guide & Specs
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Overview
The Siemens 3RU61161DB1 Overload Relay addresses the critical industrial challenge of motor burnout prevention in demanding applications. This compact thermal overload relay provides reliable protection for small motors operating in the 2.2-3.2A range, eliminating costly downtime and equipment damage caused by overload conditions, phase failure, and current imbalance.
Technical Analysis
The Siemens 3RU61161DB1 represents the S00 Level 10 series, designed for precise motor protection in compact control panel applications. This overload relay features independent installation with main circuit screw terminals and auxiliary circuit screw terminals, providing flexibility in industrial control systems. The device offers thermal memory functionality to prevent immediate restart after trip conditions, ensuring motor safety.
| Specification | Value |
|---|---|
| Current Setting Range | 2.2 - 3.2 A |
| Rated Operational Current Ie | 3.2 A |
| Utilization Category | AC-3 (Squirrel Cage Motors) |
| Trip Class | Class 10 |
| Number of Poles | 3 |
| Mounting Type | Independent Installation |
| Terminal Type | Screw Terminals |
| Auxiliary Contacts | 1 NO + 1 NC |
| Ambient Temperature Range | -25°C to +60°C |
| Protection Degree | IP20 |
| Standards Compliance | IEC/EN 60947-4-1, UL 508 |
Application Guide
This Siemens overload relay is specifically engineered for protecting small three-phase motors in applications such as pumps, fans, compressors, and conveyor systems. The Class 10 trip characteristic provides fast response to overload conditions, making it ideal for motors with high starting currents or applications requiring quick protection. The device integrates seamlessly with contactors and other motor control components in industrial automation systems.
Buying Considerations
When selecting the Siemens 3RU61161DB1 overload relay, consider these critical factors:
- Motor Current Rating: Verify your motor's full load current falls within the 2.2-3.2A setting range
- Application Requirements: Class 10 trip time is suitable for most standard applications but may need adjustment for motors with special starting characteristics
- Panel Space: Independent mounting requires adequate space allocation in your control cabinet
- Compatibility: Ensure compatibility with your existing circuit breakers and motor starters
- Environmental Conditions: IP20 protection is suitable for indoor industrial environments but may require additional enclosure for harsh conditions
Frequently Asked Questions
What does Class 10 trip time mean for motor protection?
Class 10 indicates the overload relay will trip within 10 seconds at 600% of the set current. This fast response time provides excellent protection for motors that cannot withstand prolonged overload conditions, making it suitable for most standard industrial applications.
Can the Siemens 3RU61161DB1 be used with single-phase motors?
No, this is a three-phase overload relay designed specifically for three-phase motor protection. For single-phase applications, you would need to select appropriate single-phase motor protection devices.
How do I properly set the current range on this overload relay?
The current setting is adjusted using the dial on the front of the relay. Set the dial to match your motor's full load current rating, ensuring it falls within the 2.2-3.2A range. Always refer to the motor nameplate and consult the manufacturer's documentation for precise adjustment procedures.
