Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines.
ISO 80000-3:2019 defines a unit of rotation as the dimensionless unit equal to 1, which it refers to as a revolution, but does not define the revolution as a unit. It defines a unit of rotational frequency equal to s−1.[1] The superseded standard ISO 80000-3:2006 did however state with reference to the unit name 'one', symbol '1', that "The special name revolution, symbol r, for this unit is widely used in specifications on rotating machines."
Although they have the same dimensions (s−1), hertz (Hz) and radian per second (rad/s) are two different units and are used to measure two different but proportional ISQ quantities: frequency and angular frequency (angular speed, magnitude of angular velocity) respectively. The conversions between a frequency f and an angular velocity ω are:
Thus a disc rotating at 60 rpm is said to be have an angular speed of 2π rad/s and a rotation frequency of 1 Hz.
Examples
On many kinds of disc recording media, the rotational speed of the medium under the read head is a standard given in rpm. Phonograph (gramophone) records, for example, typically rotate steadily at 16+2⁄3, 33+1⁄3, 45 or 78 rpm (0.28, 0.55, 0.75, or 1.3 Hz respectively).
Modern air turbine dental drills can rotate at up to 800,000 rpm (13.3 kHz).
The second hand of a conventional analog clock rotates at 1 rpm.
Audio CD players read their discs at a precise, constant rate (4.3218 Mbit/s of raw physical data for 1.4112 Mbit/s (176.4 kB/s) of usable audio data) and thus must vary the disc's rotational speed from 8 Hz (480 rpm) when reading at the innermost edge, to 3.5 Hz (210 rpm) at the outer edge.[2]
DVD players also usually read discs at a constant linear rate. The disc's rotational speed varies from 25.5 Hz (1530 rpm) when reading at the innermost edge, to 10.5 Hz (630 rpm) at the outer edge.[2]
A washing machine's drum may rotate at 500 to 2,000 rpm (8–33 Hz) during the spin cycles.
Modern automobileengines are typically operated around 2,000–3,000 rpm (33–50 Hz) when cruising, with a minimum (idle) speed around 750–900 rpm (12.5–15 Hz), and an upper limit anywhere from 4500 to 10,000 rpm (75–166 Hz) for a road car, very rarely reaching up to 12,000 rpm for certain cars (such as the GMA T.50), or 20,000 rpm for racing engines such as those in Formula 1 cars (during the 2006 season, with the 2.4 L N/A V8 engine configuration; limited to 15,000 rpm, with the 1.6 L V6turbo-hybrid engine configuration).[4] The exhaust note of V8, V10, and V12F1 cars has a much higher pitch than an I4 engine, because each of the cylinders of a four-stroke engine fires once for every two revolutions of the crankshaft. Thus an eight-cylinder engine turning 300 times per second will have an exhaust note of 1,200 Hz.
A piston aircraft engine typically rotates at a rate between 2,000 and 3,000 rpm (30–50 Hz).
Computer hard drives typically rotate at 5,400 or 7,200 rpm (90 or 120 Hz), the most common speeds for the ATA or SATA-based drives in consumer models. High-performance drives (used in fileservers and enthusiast-gaming PCs) rotate at 10,000 or 15,000 rpm (160 or 250 Hz), usually with higher-level SATA, SCSI or Fibre Channel interfaces and smaller platters to allow these higher speeds, the reduction in storage capacity and ultimate outer-edge speed paying off in much quicker access time and average transfer speed thanks to the high spin rate. Until recently, lower-end and power-efficient laptop drives could be found with 4,200 or even 3,600 rpm spindle speeds (70 and 60 Hz), but these have fallen out of favour due to their lower performance, improvements in energy efficiency in faster models and the takeup of solid-state drives for use in slimline and ultraportable laptops. Similar to CD and DVD media, the amount of data that can be stored or read for each turn of the disc is greater at the outer edge than near the spindle; however, hard drives keep a constant rotational speed so the effective data rate is faster at the edge (conventionally, the "start" of the disc, opposite to a CD or DVD).
Floppy disc drives typically ran at a constant 300 or occasionally 360 rpm (a relatively slow 5 or 6 Hz) with a constant per-revolution data density, which was simple and inexpensive to implement, though inefficient. Some designs such as those used with older Apple computers (Lisa, early Macintosh, later II's) were more complex and used variable rotational speeds and per-track storage density (at a constant read/record rate) to store more data per disc; for example, between 394 rpm (with 12 sectors per track) and 590 rpm (8 sectors) with Mac's 800 KB double-density drive at a constant 39.4 kB/s (max) – versus 300 rpm, 720 KB and 23 kB/s (max) for double-density drives in other machines.[5]
Gas turbine engines rotate at tens of thousands of rpm. JetCat model aircraft turbines are capable of over 100,000 rpm (1,700 Hz) with the fastest reaching 165,000 rpm (2,750 Hz).[7]
A Flywheel energy storage system works at 60,000–200,000 rpm (1–3 kHz) range using a passively magnetic levitated flywheel in a vacuum.[8] The choice of the flywheel material is not the most dense, but the one that pulverises the most safely, at surface speeds about 7 times the speed of sound.
A typical 80 mm, 30 CFM computer fan will spin at 2,600–3,000 rpm (43–50 Hz) on 12-V DC power.
A turbocharger can reach 290,000 rpm (4.8 kHz), while 80,000–200,000 rpm (1–3 kHz) is common.
A supercharger can spin at speeds between or as high as 50,000-65,000 rpm (833–1083 Hz)
Molecular microbiology – molecular engines. The rotation rates of bacterial flagella have been measured to be 10,200 rpm (170 Hz) for Salmonella typhimurium, 16,200 rpm (270 Hz) for Escherichia coli, and up to 102,000 rpm (1,700 Hz) for polar flagellum of Vibrio alginolyticus, allowing the latter organism to move in simulated natural conditions at a maximum speed of 540 mm/h.[9]
See also
Constant angular velocity (CAV) – used when referring to the speed of gramophone (phonograph) records
^ ab. DVD Technical Notes. Moving Picture Experts Group (MPEG). 1996-07-21. Archived from the original on 2012-02-19. Retrieved 2008-05-30.
^Chichester, Ryan (June 10, 2021). "The Athletic's Eno Sarris talks Spider Tack, Gerrit Cole with Moose & Maggie". WFAN. Retrieved June 14, 2021 – via MSN.com.
^"2014 season changes". Formula One. Retrieved 2014-08-18.
^"Double-Density Versus High-Density Disks". Apple. Retrieved 2012-05-05.
^"Slender and Elegant, It Fuels the Bomb". The Electricity Forum. Retrieved 2006-09-24.
^. JetCat USA. Archived from the original on 2012-04-19. Retrieved 2006-07-19.
^Post, Richard F. (April 1996). "A New Look at an Old Idea: The Electromechanical Battery" (PDF). Science & Technology Review. University of California: 12–19. ISSN 1092-3055. Retrieved 2008-05-30.
revolutions, minute, other, uses, disambiguation, redirects, here, other, uses, disambiguation, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challeng. For other uses see Revolutions per minute disambiguation rpm redirects here For other uses see rpm disambiguation This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Revolutions per minute news newspapers books scholar JSTOR July 2016 Learn how and when to remove this template message Revolutions per minute abbreviated rpm RPM rev min r min or with the notation min 1 is a unit of rotational speed or rotational frequency for rotating machines Revolution per minuteUnit ofRotational speedSymbolrpm or r minConversions1 rpm in is equal to SI units 1 60 Hz 0 016 Hz SI base units 0 016 s 1 Contents 1 Standards 2 Examples 3 See also 4 ReferencesStandards EditISO 80000 3 2019 defines a unit of rotation as the dimensionless unit equal to 1 which it refers to as a revolution but does not define the revolution as a unit It defines a unit of rotational frequency equal to s 1 1 The superseded standard ISO 80000 3 2006 did however state with reference to the unit name one symbol 1 that The special name revolution symbol r for this unit is widely used in specifications on rotating machines The International System of Units SI does not recognize rpm as a unit and defines the unit of frequency Hz as equal to s 1 1 Hz 60 rpm 1 60 Hz 1 rpm displaystyle begin aligned 1 amp text Hz amp amp amp 60 amp text rpm frac 1 60 amp text Hz amp amp amp 1 amp text rpm end aligned A corresponding but distinct quantity for describing rotation is angular velocity for which the SI unit is the radian per second Although they have the same dimensions s 1 hertz Hz and radian per second rad s are two different units and are used to measure two different but proportional ISQ quantities frequency and angular frequency angular speed magnitude of angular velocity respectively The conversions between a frequency f and an angular velocity w are w 2 p f f w 2 p displaystyle omega 2 pi f qquad f frac omega 2 pi Thus a disc rotating at 60 rpm is said to be have an angular speed of 2p rad s and a rotation frequency of 1 Hz Examples EditOn many kinds of disc recording media the rotational speed of the medium under the read head is a standard given in rpm Phonograph gramophone records for example typically rotate steadily at 16 2 3 33 1 3 45 or 78 rpm 0 28 0 55 0 75 or 1 3 Hz respectively Modern air turbine dental drills can rotate at up to 800 000 rpm 13 3 kHz The second hand of a conventional analog clock rotates at 1 rpm Audio CD players read their discs at a precise constant rate 4 3218 Mbit s of raw physical data for 1 4112 Mbit s 176 4 kB s of usable audio data and thus must vary the disc s rotational speed from 8 Hz 480 rpm when reading at the innermost edge to 3 5 Hz 210 rpm at the outer edge 2 DVD players also usually read discs at a constant linear rate The disc s rotational speed varies from 25 5 Hz 1530 rpm when reading at the innermost edge to 10 5 Hz 630 rpm at the outer edge 2 A washing machine s drum may rotate at 500 to 2 000 rpm 8 33 Hz during the spin cycles A baseball thrown by a Major League Baseball pitcher can rotate at over 2 500 rpm 41 7 Hz faster rotation yields more movement on breaking balls 3 A power generation turbine with a two pole alternator rotates at 3000 rpm 50 Hz or 3600 rpm 60 Hz depending on country see AC power plugs and sockets Modern automobile engines are typically operated around 2 000 3 000 rpm 33 50 Hz when cruising with a minimum idle speed around 750 900 rpm 12 5 15 Hz and an upper limit anywhere from 4500 to 10 000 rpm 75 166 Hz for a road car very rarely reaching up to 12 000 rpm for certain cars such as the GMA T 50 or 20 000 rpm for racing engines such as those in Formula 1 cars during the 2006 season with the 2 4 L N A V8 engine configuration limited to 15 000 rpm with the 1 6 L V6 turbo hybrid engine configuration 4 The exhaust note of V8 V10 and V12 F1 cars has a much higher pitch than an I4 engine because each of the cylinders of a four stroke engine fires once for every two revolutions of the crankshaft Thus an eight cylinder engine turning 300 times per second will have an exhaust note of 1 200 Hz A piston aircraft engine typically rotates at a rate between 2 000 and 3 000 rpm 30 50 Hz Computer hard drives typically rotate at 5 400 or 7 200 rpm 90 or 120 Hz the most common speeds for the ATA or SATA based drives in consumer models High performance drives used in fileservers and enthusiast gaming PCs rotate at 10 000 or 15 000 rpm 160 or 250 Hz usually with higher level SATA SCSI or Fibre Channel interfaces and smaller platters to allow these higher speeds the reduction in storage capacity and ultimate outer edge speed paying off in much quicker access time and average transfer speed thanks to the high spin rate Until recently lower end and power efficient laptop drives could be found with 4 200 or even 3 600 rpm spindle speeds 70 and 60 Hz but these have fallen out of favour due to their lower performance improvements in energy efficiency in faster models and the takeup of solid state drives for use in slimline and ultraportable laptops Similar to CD and DVD media the amount of data that can be stored or read for each turn of the disc is greater at the outer edge than near the spindle however hard drives keep a constant rotational speed so the effective data rate is faster at the edge conventionally the start of the disc opposite to a CD or DVD Floppy disc drives typically ran at a constant 300 or occasionally 360 rpm a relatively slow 5 or 6 Hz with a constant per revolution data density which was simple and inexpensive to implement though inefficient Some designs such as those used with older Apple computers Lisa early Macintosh later II s were more complex and used variable rotational speeds and per track storage density at a constant read record rate to store more data per disc for example between 394 rpm with 12 sectors per track and 590 rpm 8 sectors with Mac s 800 KB double density drive at a constant 39 4 kB s max versus 300 rpm 720 KB and 23 kB s max for double density drives in other machines 5 A Zippe type centrifuge for enriching uranium spins at 90 000 rpm 1 500 Hz or faster 6 Gas turbine engines rotate at tens of thousands of rpm JetCat model aircraft turbines are capable of over 100 000 rpm 1 700 Hz with the fastest reaching 165 000 rpm 2 750 Hz 7 A Flywheel energy storage system works at 60 000 200 000 rpm 1 3 kHz range using a passively magnetic levitated flywheel in a vacuum 8 The choice of the flywheel material is not the most dense but the one that pulverises the most safely at surface speeds about 7 times the speed of sound A typical 80 mm 30 CFM computer fan will spin at 2 600 3 000 rpm 43 50 Hz on 12 V DC power A millisecond pulsar can have near 50 000 rpm 833 Hz A turbocharger can reach 290 000 rpm 4 8 kHz while 80 000 200 000 rpm 1 3 kHz is common A supercharger can spin at speeds between or as high as 50 000 65 000 rpm 833 1083 Hz Molecular microbiology molecular engines The rotation rates of bacterial flagella have been measured to be 10 200 rpm 170 Hz for Salmonella typhimurium 16 200 rpm 270 Hz for Escherichia coli and up to 102 000 rpm 1 700 Hz for polar flagellum of Vibrio alginolyticus allowing the latter organism to move in simulated natural conditions at a maximum speed of 540 mm h 9 See also EditConstant angular velocity CAV used when referring to the speed of gramophone phonograph records Constant linear velocity CLV used when referring to the speed of audio CDs Radian per second Rotational speed Compressor map Turn geometry Idle speed Overspeed engine Redline Rev limiterReferences Edit ISO 80000 3 2019 a b Physical parameters DVD Technical Notes Moving Picture Experts Group MPEG 1996 07 21 Archived from the original on 2012 02 19 Retrieved 2008 05 30 Chichester Ryan June 10 2021 The Athletic s Eno Sarris talks Spider Tack Gerrit Cole with Moose amp Maggie WFAN Retrieved June 14 2021 via MSN com 2014 season changes Formula One Retrieved 2014 08 18 Double Density Versus High Density Disks Apple Retrieved 2012 05 05 Slender and Elegant It Fuels the Bomb The Electricity Forum Retrieved 2006 09 24 P60 SE Special Edition JetCat USA Archived from the original on 2012 04 19 Retrieved 2006 07 19 Post Richard F April 1996 A New Look at an Old Idea The Electromechanical Battery PDF Science amp Technology Review University of California 12 19 ISSN 1092 3055 Retrieved 2008 05 30 Magariyama Y Sugiyama S Muramoto K Maekawa Y Kawagishi I Imae Y Kudo S October 27 1994 Very fast flagellar rotation Nature 371 6500 752 Bibcode 1994Natur 371 752M doi 10 1038 371752b0 PMID 7935835 Retrieved from https en wikipedia org w index php title Revolutions per minute amp oldid 1127020159, wikipedia, wiki, book, books, library,
