Basler 9-1051-00-105 Overload Protection Module
The Basler 9-1051-00-105 is a solid‑state overload protection module designed to protect motors, transformers, and feeders from thermal damage caused by excessive current. This module provides both thermal overload and short‑circuit protection, with adjustable trip curves that mimic the thermal characteristics of the protected equipment.
Protection Principle
The module measures the RMS current through an external CT and calculates the thermal heat generated using an I²t algorithm. It models the heating and cooling of the protected device, tripping when the accumulated heat exceeds a safe limit. This thermal model accounts for both continuous and intermittent overloads, providing more accurate protection than simple overcurrent relays.
Key Features
True RMS current sensing for accurate overload detection.
Adjustable trip class (5, 10, 20, 30) for motor protection.
Selectable time‑current curves (standard or inverse).
Manual reset and automatic reset options.
LED indication for power, trip, and alarm.
Wide auxiliary supply: 24–250 VDC or 120/240 VAC.
Compact DIN‑rail mountable housing.
Technical Specifications
The module operates with a current input range of 1–10 A from a 5 A CT secondary. The frequency range is 50/60 Hz. The trip class settings correspond to standard motor starting times: Class 5 (5 seconds), Class 10, Class 20, and Class 30. The accuracy of the thermal model is ±5 % of the trip time. The output relay is rated 5 A at 250 VAC. Operating temperature: -20 °C to +60 °C.
Installation and Wiring
Mount the module on a DIN rail inside the control panel. Connect the CT secondary leads to the input terminals. The auxiliary supply is connected to the power terminals. The output relay contact is wired to the trip coil of the contactor or circuit breaker. For manual reset, a push‑button can be connected to the reset terminals.
Setting the Trip Class
Select the appropriate trip class based on the motor’s starting time and thermal withstand capability. For motors with a short starting time, Class 5 may be suitable; for longer starts or heavy loads, Class 20 or 30 may be required. The module also allows selection of an inverse‑time curve for better coordination with other protective devices.
Applications
Commonly used for thermal overload protection of AC motors, pump systems, conveyor drives, and compressors. It is also applied to protect distribution transformers and feeder circuits against prolonged overloads.
Testing and Commissioning
Perform a secondary injection test by applying an overcurrent to the CT input. Measure the trip time and compare it with the selected trip class. Verify that the alarm output (if used) operates at a preset percentage of the trip threshold.
Maintenance
Periodically check for loose connections and dust. Test the module annually to ensure accurate tripping. The module has no user‑serviceable parts.
Advantages
Compared to bimetallic overload relays, the 9-1051-00-105 offers better accuracy, wider adjustability, and resistance to ambient temperature changes. Its thermal memory function ensures proper protection even for repeated start‑stop cycles.
Compliance
Designed to meet IEC 60947 and UL 508 standards.
Conclusion
The Basler 9-1051-00-105 Overload Protection Module provides reliable thermal protection for industrial equipment, enhancing safety and reducing downtime.
