Overview#
The Caterpillar C18 ACERT is a 600 kW standby diesel generator that represents the highest-output inline-6 configuration in Cat's ACERT standby generator lineup. Displacing 18.1 liters in a six-cylinder package with a 145 mm x 183 mm bore and stroke, the C18 delivers exceptional power density. It is a preferred choice for mid-to-large hospitals, educational campuses, and commercial buildings that need reliable standby power with a smaller physical footprint than a V12 unit.
The C18 delivers 600 ekW (750 kVA) standby and 545 ekW (681 kVA) prime at 60 Hz, 480V or 600V, 0.8 power factor. The MEUI fuel injection system is governed by the ADEM A4 electronic governor, providing precise fuel delivery across the full load range. The generator set accepts 100% rated load in one step per NFPA 110 and meets ISO 8528-5 transient response requirements.
The C18 supports 4160V medium-voltage output alongside standard utilization voltages -- a meaningful advantage for hospitals and campuses with medium-voltage distribution infrastructure. As an active Cat product, the C18 enjoys full factory support, regular parts availability, and an extensive dealer service network across California.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby rating | 600 ekW / 750 kVA |
| Prime rating | 545 ekW / 681 kVA |
| Frequency | 60 Hz |
| Speed | 1800 rpm |
| Voltages | 480V, 600V, 4160V |
| Engine model | Cat C18 ACERT |
| Displacement | 18.1 L (1,106 in³) |
| Bore x stroke | 145 mm x 183 mm (5.7 in x 7.2 in) |
| Compression ratio | 14.5:1 |
| Aspiration | Turbocharged Air-to-Air Aftercooled |
| Fuel injection | MEUI |
| Governor | ADEM A4 |
| Emissions | EPA Tier 2 (Stationary Emergency) |
| Fuel consumption @ 100% load (standby) | 42.7 gal/hr (161.6 L/hr) |
| Fuel consumption @ 75% load (standby) | 34.2 gal/hr (129.6 L/hr) |
| Fuel consumption @ 50% load (standby) | 24.2 gal/hr (91.7 L/hr) |
| Fuel consumption @ 25% load (standby) | 12.4 gal/hr (46.8 L/hr) |
| Combustion air flow | 1,687.8 cfm at full load |
| Exhaust gas temperature | 994 degrees F at full load |
| Alternator frame | LC7024F (480V) / LC7024H (600V) |
| Motor starting @ 30% voltage dip | 1,633 skVA (480V) / 2,023 skVA (600V) |
| Controller | EMCP 4.2 standard, EMCP 4.3/4.4 optional |
Our Service Experience#
We regularly maintain C18 units in hospital and campus environments where high availability is non-negotiable. The ACERT technology's advanced air management improves transient response compared to earlier Cat inline-6 platforms, and we find the C18 handles large step-load applications -- such as MRI equipment startup -- reliably at 60 Hz, 480V.
The 18.1-liter engine has more coolant and lube oil capacity than smaller C-Series models, so oil analysis via Cat S-O-S is particularly important for establishing wear metal baselines during the low run-hours typical of standby service. Weather-protective enclosures are popular for outdoor rooftop and pad installations at Bay Area sites where fog and salt air are factors. Medium-voltage 4160V configurations require coordination with a licensed electrical contractor for ATS and switchgear integration.
Frequently Asked Questions#
What is the standby rating of the Caterpillar C18? The Cat C18 ACERT is rated at 600 ekW (750 kVA) standby and 545 ekW (681 kVA) prime at 60 Hz / 1800 rpm / 480V or 600V / 0.8 power factor.
What engine does the Cat C18 use? The C18 ACERT -- an 18.1-liter inline-6, four-stroke turbocharged air-to-air aftercooled diesel with a 145 mm x 183 mm bore and stroke and 14.5:1 compression ratio. MEUI fuel injection with ADEM A4 electronic governor. EPA Tier 2 certified for stationary emergency use.
What is the fuel consumption of the Cat C18 generator? At 600 ekW standby, the C18 ACERT consumes 42.7 gal/hr at 100% load, 34.2 gal/hr at 75% load, 24.2 gal/hr at 50% load, and 12.4 gal/hr at 25% load on No. 2 diesel fuel.
Does the C18 support 4160V medium-voltage output? Yes. The C18 is available in a 4160V medium-voltage configuration in addition to standard 277/480V and 346/600V.
How does the C18 compare to the C13 and C27? The C18 (18.1L, 600 kW standby) slots between the C13 (12.5L, 350 kW) and the C27 (27.03L V12, 800 kW). The C18 is the highest-output inline-6 in Cat's ACERT standby range; the C27 steps up to a V12 for loads above 600 kW.
