The GE MPRO 18 PLUS LLA11YY978 is a sophisticated electronic trip unit specifically designed for the M-Pact Plus series of Air Circuit Breakers (ACB). This “18 Plus” variant provides high-precision protection for low-voltage power distribution systems, offering a comprehensive suite of functions including long-time, short-time, and instantaneous protection. Equipped with discrete LEDs for fault analysis and a healthy unit indicator, it ensures reliable operation and rapid troubleshooting in critical industrial and commercial electrical networks.
Product Specifications
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Model Series: MPRO 18 Plus (M-Pact Plus)
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Part Number: LLA11YY978
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Dimensions: Approximately 110 mm x 105 mm x 85 mm
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Weight: Approximately 0.75 kg
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Country of Origin: United Kingdom / Poland (GE Industrial Systems)
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Long Time Protection: Adjustable pickup (0.4 to 1.0x In) with selectable time delay classes (Class 20/40)
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Short Time Protection: Fixed or adjustable (1.5 to 12x Ir) with I²t protection options
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Instantaneous Trip: Adjustable (2 to 12x In) or OFF
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Input Power Support: Supports 24-48V DC or 110-250V AC/DC configurations
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Fault History: Stores records of the last 16 trip events for analysis
Application Fields
This trip unit is primarily used within GE M-Pact Plus Air Circuit Breakers to protect power distribution systems in heavy industries, large-scale data centers, and commercial infrastructure. It is essential for protecting electrical equipment from overloads and short circuits while maintaining system selectivity. Its robust design allows it to perform in environments requiring precise coordination between upstream and downstream breakers to minimize downtime during localized faults.
Product Instructions
The MPRO 18 PLUS is a plug-and-play electronic module that should be installed into the front compartment of a compatible M-Pact Plus ACB. Ensure the breaker is in the “OFF” position and the springs are discharged before attempting installation or replacement. Use the rotary switches on the front panel to set the protection parameters according to the electrical engineering study of your facility. A 26-way D-type connector or a test kit port is available on the face of the unit for secondary injection testing. Regularly verify the “Healthy Unit” LED status to confirm the internal self-supervision is active and the unit is ready for protection duty.
FAQ: Common Questions and Answers
Q: Can I replace an older MPRO 17 unit with the MPRO 18 PLUS? A: Yes, the 18 PLUS is an upgraded version offering enhanced functionality and better LED diagnostics. However, you must verify that the current transformer (CT) ratios and frame sizes are compatible with the new unit’s settings.
Q: What do the different colored LEDs on the front indicate? A: Typically, a green LED indicates a healthy unit and active auxiliary power. Yellow or red LEDs signify specific trip causes, such as Overload (L), Short Circuit (S), or Instantaneous (I), helping maintenance teams identify the nature of a fault.
Q: Does the unit require a battery to function? A: While the unit can operate on internal CT power during a fault, an internal battery pack or external auxiliary power is often used to maintain the fault LEDs and history records after a trip has occurred.
For technical datasheets and professional replacement services for the GE MPRO 18 PLUS LLA11YY978, please consult our technical catalog.
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GE MPRO 50 (Next-Generation Digital Trip Unit)
