Convert Radians per hour to Revolutions per minute
Convert Radians per hour (rad/h) to Revolutions per minute (rpm) instantly and accurately.
Conversion Formula
rpm = rad/h × 0.002652582385
About Radians per hour
The radian per hour (rad/h) equals 1/3600 rad/s ≈ 2.778 × 10⁻⁴ rad/s. In tidal harmonic analysis, constituents are characterised by their angular speed in rad/h: the principal lunar M₂ tide has σ ≈ 0.5059 rad/h; the solar S₂ exactly π/6 ≈ 0.5236 rad/h. A geostationary satellite tracks at 2π/24 ≈ 0.2618 rad/h - the same as Earth's sidereal rate, which equatorial telescope drives must match to follow stars. Rotary cement kilns (up to 230 m long) rotate at 0.1-0.5 rad/h. 1 rad/h = 1/3600 rad/s ≈ 0.1592 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
| Radians per hour (rad/h) | Revolutions per minute (rpm) |
|---|---|
| 1 rad/h | 0.00265258 rpm |
| 2 rad/h | 0.00530516 rpm |
| 5 rad/h | 0.0132629 rpm |
| 10 rad/h | 0.0265258 rpm |
| 25 rad/h | 0.0663146 rpm |
| 50 rad/h | 0.132629 rpm |
| 100 rad/h | 0.265258 rpm |