Convert Revolutions per hour to Revolutions per minute
Convert Revolutions per hour (rev/h) to Revolutions per minute (rpm) instantly and accurately.
Conversion Formula
rpm = rev/h × 0.01666666667
About Revolutions per hour
The revolution per hour (rev/h) equals π/1800 rad/s ≈ 1.745 × 10⁻³ rad/s, used for very slow rotating machinery. Cement rotary kilns - the world's longest continuously rotating machines (up to 230 m, 4000 t) - rotate at 1-5 rev/h; ball mills for ore grinding at 10-20 rev/h; concrete mixer trucks at 1-4 rev/h during transport. Large astronomical antenna drives and slow-scan telescope azimuth movements are also conveniently expressed in rev/h. 1 rev/h = π/1800 rad/s ≈ 0.02778 rpm.
About Revolutions per minute
The revolution per minute (rpm) equals π/30 rad/s ≈ 0.1047 rad/s, the most universally recognised rotational speed unit in mechanical engineering. Common references: car petrol engines idle at 600-900 rpm, redline at 5500-8500 rpm; large marine diesel engines run at 75-120 rpm; electric induction motor synchronous speed = 60f/p rpm (3000 rpm at 50 Hz, 2-pole); hard drives at 5400-15000 rpm; dental turbines up to 400000 rpm; washing machine spin 400-1600 rpm. ISO 6336 and ANSI/AGMA gear standards use rpm throughout. 1 rpm = π/30 rad/s = 6 °/s = 1/60 rps.
Quick Reference Table
| Revolutions per hour (rev/h) | Revolutions per minute (rpm) |
|---|---|
| 1 rev/h | 0.0166667 rpm |
| 2 rev/h | 0.0333333 rpm |
| 5 rev/h | 0.0833333 rpm |
| 10 rev/h | 0.166667 rpm |
| 25 rev/h | 0.416667 rpm |
| 50 rev/h | 0.833333 rpm |
| 100 rev/h | 1.66667 rpm |