Kohler 125KW 120/208V 3-Phase Standby Generator Aluminum New - KG125R-QS5
Reliable power for very large residential or small business needs. Built to weather the storms, our largest natural gas/liquid propane generators with industrial-grade engines keep your family comfortable and your business running when a utility failure or storm knocks out power.
What our Experts Think
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Heavy-duty commercial & large facility standby
With 125 kW of 120/208 V three-phase power, this generator is built for large commercial buildings, industrial sites, and mission-critical backup applications that require substantial, balanced power delivery.
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Industrial-grade liquid-cooled performance
Powered by a Kohler 6.2 L liquid-cooled engine, it runs at 1800 RPM for efficient, quieter operation under heavy load and long standby duty cycles.
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Premium power quality with low distortion
Advanced voltage and frequency regulation plus ultra-low total harmonic distortion ensure clean, stable power, protecting sensitive electronics and control systems.
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Fast automatic response & reliability
The Fast-Response excitation system handles full loads within about 10 seconds of an outage, minimizing downtime for critical operations.
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Rugged aluminum enclosure
Sound-attenuating, corrosion-resistant aluminum housing with high wind load rating (up to 186 mph) provides weather durability and quieter operation (~70 dB @ 7 m).
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Advanced APM402 controller
Integrated controller delivers system monitoring, diagnostics, and local data access, making maintenance and oversight easier for facility managers.
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Dual-fuel flexibility (NG & LP)
Designed to run on natural gas or liquid propane with simple field conversion while maintaining emissions compliance.
Q&A
Q1: What is this generator designed for?
A: A 125 kW 120/208 V 3-phase standby generator is engineered for large commercial buildings, light industrial facilities, and very large residential three-phase systems requiring dependable backup power.
Q2: What fuel types does it support?
A: It runs on clean-burning natural gas or liquid propane (LP) with simple field conversion while maintaining emissions certification.
Q3: Does it automatically restore power during outages?
A: Yes — paired with an automatic transfer switch (not included), it starts and restores power within about 10 seconds of a utility failure.
Q4: What engine and performance features are included?
A: Powered by an industrial-grade Kohler 6.2 L liquid-cooled engine running at 1800 RPM for efficient, reliable operation with excellent voltage and frequency regulation.
Q5: Is the power quality suitable for sensitive equipment?
A: Yes — advanced regulation and ultra-low total harmonic distortion (THD) deliver clean power for sensitive electronics and systems.
Q6: How quiet and durable is it?
A: The sound-attenuating aluminum enclosure with acoustic insulation keeps noise around ~70 dB at 7 m and resists corrosion, scratches, and high wind loads.
Q7: What control and monitoring features are available?
A: It includes a Kohler APM402 controller with advanced system diagnostics; remote monitoring options are supported (sold separately).
Maintenance Tips
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Run Weekly Exercise Cycle
Perform automatic self-test (20–30 minutes) to keep engine lubricated and system ready for emergency load.
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Change Oil, Filters & Fluids on Schedule
Follow service intervals for oil, oil filter, fuel filter, and air filter to maintain peak engine performance and efficiency.
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Inspect Battery & Charging System Monthly
Ensure strong voltage, clean terminals, and proper charger function for reliable automatic startup.
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Monitor Fuel System (NG/LP)
Check regulators, fuel pressure, and line integrity for stable high-load 3-phase operation.
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Check Cooling System
Verify coolant levels, radiator condition, and airflow to prevent overheating under heavy commercial loads.
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Clean Air Intake & Aluminum Enclosure
Keep vents clear of dust, debris, and obstruction to maintain cooling efficiency and corrosion resistance.
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Test Under Full Load Periodically
Simulate real facility demand to confirm voltage stability, frequency control, and phase balance.
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Inspect Electrical Connections
Tighten lugs, breakers, and transfer switch wiring to ensure safe high-amperage operation.
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Monitor Controller Diagnostics
Review alarms, runtime logs, and system health indicators for early fault detection.
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