When we bid on grading and paving projects in high-elevation environments—such as ski resorts or mountain highway passes sitting at 2,500 meters [approx. 8,200 feet] above sea level—the physics of the atmosphere dictate our equipment choices. Internal combustion engines are fundamentally air pumps. A gasoline or diesel plate compactor relies on a precise stoichiometric ratio of air to fuel (roughly 14.7 parts air to 1 part fuel for gasoline) to generate its rated horsepower.
At high altitudes, the air pressure drops significantly, and the air becomes "thin" (less dense). For every 300 meters [approx. 1,000 feet] of elevation gained, a naturally aspirated combustion engine loses roughly 3% of its power. If I take a high-output gasoline plate compactor rated at 9 horsepower at sea level up to a mountain pass, it might barely output 6.5 horsepower. The engine runs incredibly "rich," fouling spark plugs, blowing black soot, and struggling to spin the heavy eccentric weights up to their optimal VPM. We constantly have to re-jet the carburetors or adjust the diesel injection pumps just to keep the machines from stalling under load.
This is arguably the most brilliant use-case for the commercial electric plate compactor. An electric motor does not "breathe." Its torque generation relies entirely on electromagnetism, which is entirely immune to atmospheric pressure and air density. An electric plate delivers the exact same blistering torque and maintains the exact same peak vibration frequency at 3,000 meters [approx. 10,000 feet] as it does at sea level. When managing high-altitude jobs, the electric fleet guarantees consistent compaction performance without the endless mechanic downtime required to tune gas and diesel engines to the thin mountain air.
