Definition

Noun 1. A unit of rotational speed: A measurement of how many complete turns or cycles a rotating object makes in one minute. It is a standard unit for expressing the speed of engines, motors, fans, turntables, and other mechanical components.

Usage

• Revolutions per minute is used to quantify the rotational speed of an axle, shaft, disk, or rotor.
• It is commonly abbreviated as rpm or RPM.
• It functions as a noun phrase, often following a number (e.g., 3000 revolutions per minute).

Examples

• The old vinyl record spins at 33 1/3 revolutions per minute.
• A typical car engine idles at around 800 revolutions per minute.
• The technician measured the fan's speed at 1200 rpm.

Advanced Usage

• Technical Specification: RPM is a critical specification for motors and engines, indicating their operating speed and power band.
  • The motor's maximum torque is achieved at 2500 revolutions per minute.
• Comparative Analysis: Used to compare the rotational speeds of different devices or under different conditions.
  • Drilling at a higher number of revolutions per minute produces a smoother finish on wood.

Variants and Related Words

• rpm / RPM (noun): The standard abbreviation for "revolutions per minute."
  • The tachometer shows the engine speed in rpm.
• Rev (noun, informal): A single revolution, especially of an engine. Often used in plural ("revs") to colloquially indicate RPM.
  • Give it more revs!
• Rotational Speed (noun): The more general term for which revolutions per minute is a specific unit of measurement.
• Hertz (Hz) (noun): The SI unit of frequency, measured in cycles per second. While related, it is not directly interchangeable with RPM (1 Hz = 60 rpm).

Synonyms

• Rotational frequency (per minute): A more technical synonym.
• Rotational speed: A broader, more general synonym.

Related Phrases

• To rev (up) to [number] rpm (phrasal verb): To increase the engine speed to a specified rotational velocity.
  • He revved the engine to 5000 rpm.
• At a constant [number] rpm: Operating without variation in rotational speed.
  • The centrifuge must run at a constant 10,000 rpm.

Noun

1. rate of revolution of a motor
   • the engine was doing 6000 revs