Overview#
The Cummins RS50 is a 50 kW liquid-cooled residential standby generator from the QuietConnect RS Series. It marks the transition from the compact 2.4-liter 4-cylinder platform to the larger 5.9-liter inline 6-cylinder engine (QSJ5.9G), providing significantly more power and motor starting capacity for estate homes and large residential properties.
The RS50 runs on natural gas or propane vapor (field selectable) at 1,800 rpm and produces 72 dB(A) at 23 feet with the powder-coated aluminum Sound Level 1 enclosure. The enclosure is wind-rated to 180 mph per ASCE 7-10 and the unit is equipped for cold weather starts down to -40 F with factory accessories. An 850 CCA battery at 0 F is required.
At 2,403 lbs and 118.7 x 40.0 x 58.3 inches, the RS50 is a substantial unit that requires proper structural support and adequate clearances. PowerCommand 1.1 controls provide electronic governing, self-diagnostics, and flexible exercise scheduling.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 50 kW |
| Voltage (1-phase) | 120/240V |
| Voltage (3-phase) | 120/208V, 277/480V |
| Frequency | 60 Hz |
| Engine Model | QSJ5.9G |
| Displacement | 5.9 L |
| Cylinders | 6 (inline) |
| Aspiration | Naturally aspirated |
| Rated Speed | 1,800 rpm |
| Cooling | Liquid-cooled |
| Voltage Regulation | ±1% |
| Frequency Regulation | ±0.25% |
| Controller | PowerCommand 1.1 |
| Sound Level | 72 dB(A) at 23 ft (7 m) |
| Dimensions (L x W x H) | 118.7 x 40.0 x 58.3 in |
| Weight | 2,403 lbs |
| Battery Requirement | 850 CCA at 0 F |
| Fuel Pressure | 1.5-3.5 kPa (6.0-13.0 in H₂O) |
| Wind Rating | 180 mph (ASCE 7-10) |
| Cold Weather | -40 F (with factory accessories) |
Our Service Experience#
The RS50 is the entry point for the 5.9L engine platform in the QuietConnect residential lineup. The QSJ5.9G engine is well-proven across thousands of residential and light commercial installations nationwide. It is mechanically similar to the commercial C-series generators (C60 N6 through C100 N6), giving us deep field experience with the platform.
Service intervals are 500 hours or annually for oil and filter, 500 hours for air filter, 1,000 hours for spark plugs (all 6 cylinders), and 30,000 hours for major overhaul. The coolant system requires annual testing and periodic replacement. Fuel pressure at the engine inlet must be verified under operating load -- minimum 6.0 in H₂O, maximum 13.0 in H₂O.
The most common maintenance issue on 5.9L QuietConnect units is spark plug condition. With 6 cylinders there are more plugs to manage, and gas engines are more sensitive to plug condition than diesel. We recommend inspecting plugs at every annual service and replacing the full set at 1,000 hours.
Frequently Asked Questions#
What is the standby rating of the RS50? 50 kW, available in single-phase (120/240V) and three-phase (120/208V, 277/480V) configurations.
How does the RS50 compare to the RS40? The RS50 uses a 5.9L inline-6 (2,403 lbs) vs the RS40's 2.4L turbo inline-4 (1,356 lbs). The RS50 provides 25% more power and runs naturally aspirated (no turbocharger to maintain). The trade-off is significantly more weight, larger footprint, and higher fuel consumption.
What is the warranty on the RS50? 2-year factory warranty from Cummins. Extended options available through authorized dealers.
