Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to 1/60hertz.
Revolutions per minute
A car's tachometer marked in multiples of a thousand rpm
Although they have the same dimensions (reciprocal time) and base unit (s−1), the hertz (Hz) and radians per second (rad/s) are special names used to express two different but proportional ISQ quantities: frequency and angular frequency, respectively. The conversions between a frequency f and an angular frequency ω are:
Thus a disc rotating at 60 rpm is said to have an angular speed of 2π rad/s and a rotation frequency of 1 Hz.
For a wheel, a pump, or a crank shaft, the number of times that it completes one full cycle in one minute is given the unit revolution per minute. A revolution is one complete period of motion, whether this be circular, reciprocating or some other periodic motion.
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 rpm or 78 rpm (0.28, 0.55, 0.75, or 1.3, respectively, in Hz).
Modern air turbine dental drills can rotate at up to 800000 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 rpm to 2000 rpm (8 Hz – 33 Hz) during the spin cycles.
Modern automobileengines are typically operated around 2000 rpm – 3000 rpm (33 Hz – 50 Hz) when cruising, with a minimum (idle) speed around 750 rpm – 900 rpm (12.5 Hz – 15 Hz), and an upper limit anywhere from 4500 rpm to 10000 rpm (75 Hz – 166 Hz) for a road car, very rarely reaching up to 12000 rpm for certain cars (such as the GMA T.50), or 20000 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 15000 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 1200 Hz.
A piston aircraft engine typically rotates at a rate between 2000 rpm and 3000 rpm (33 Hz – 50 Hz).
Computer hard drives typically rotate at 5400 rpm – 7200 rpm (90 Hz – 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 10000 rpm – 15000 rpm (160 Hz – 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 4200 rpm or even 3600 rpm spindle speeds (70 Hz or 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 rpm or occasionally 360 rpm (a relatively slow 5 Hz 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 100000 rpm (1700 Hz) with the fastest reaching 165000 rpm (2750 Hz).[7]
A Flywheel energy storage system works at 60000 rpm – 200000 rpm (1 kHz – 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 2600 rpm – 3000 rpm (43 Hz – 50 Hz) on 12 V DC power.
A turbocharger can reach 290000 rpm (4.8 kHz), while 80000 rpm – 200000 rpm (1 kHz – 3 kHz) is common.
A supercharger can spin at speeds between or as high as 50000 rpm – 65000 rpm (833 Hz – 1083 Hz)
Molecular microbiology – molecular engines. The rotation rates of bacterial flagella have been measured to be 10200 rpm (170 Hz) for Salmonella typhimurium, 16200 rpm (270 Hz) for Escherichia coli, and up to 102000 rpm (1700 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 alsoedit
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 r min 1 is a unit of rotational speed or rotational frequency for rotating machines One revolution per minute is equivalent to 1 60 hertz Revolutions per minuteA car s tachometer marked in multiples of a thousand rpmGeneral informationUnit ofRotational speed rotational frequencySymbolrpm r minConversions1 rpm in is equal to SI accepted units 1 min 1 SI units 1 60 Hz 0 016 Hz SI base units 0 016 s 1 Contents 1 Standards 2 Examples 3 See also 4 Notes 5 ReferencesStandards editISO 80000 3 2019 defines a physical quantity called rotation or number of revolutions dimensionless whose instantaneous rate of change is called rotational frequency or rate of rotation with units of reciprocal seconds s 1 1 A related but distinct quantity for describing rotation is angular frequency or angular speed the magnitude of angular velocity for which the SI unit is the radian per second rad s Although they have the same dimensions reciprocal time and base unit s 1 the hertz Hz and radians per second rad s are special names used to express two different but proportional ISQ quantities frequency and angular frequency respectively The conversions between a frequency f and an angular frequency w are w 2 p f f w 2 p displaystyle omega 2 pi f qquad f frac omega 2 pi nbsp Thus a disc rotating at 60 rpm is said to have an angular speed of 2p rad s and a rotation frequency of 1 Hz The International System of Units SI does not recognize rpm as a unit It defines units of angular frequency and angular velocity as rad s 1 and units of frequency as Hz equal to s 1 1 rad s 1 2 p Hz 60 2 p rpm 2 p rad s 1 Hz 60 rpm 2 p 60 rad s 1 60 Hz 1 rpm displaystyle begin aligned 1 amp frac text rad text s amp amp amp frac 1 2 pi amp text Hz amp amp amp frac 60 2 pi amp text rpm 2 pi amp frac text rad text s amp amp amp 1 amp text Hz amp amp amp 60 amp text rpm frac 2 pi 60 amp frac text rad text s amp amp amp frac 1 60 amp text Hz amp amp amp 1 amp text rpm end aligned nbsp Examples editFor a wheel a pump or a crank shaft the number of times that it completes one full cycle in one minute is given the unit revolution per minute A revolution is one complete period of motion whether this be circular reciprocating or some other periodic motion 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 rpm or 78 rpm 0 28 0 55 0 75 or 1 3 respectively in Hz Modern air turbine dental drills can rotate at up to 800000 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 rpm to 2000 rpm 8 Hz 33 Hz during the spin cycles A baseball thrown by a Major League Baseball pitcher can rotate at over 2500 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 2000 rpm 3000 rpm 33 Hz 50 Hz when cruising with a minimum idle speed around 750 rpm 900 rpm 12 5 Hz 15 Hz and an upper limit anywhere from 4500 rpm to 10000 rpm 75 Hz 166 Hz for a road car very rarely reaching up to 12000 rpm for certain cars such as the GMA T 50 or 20000 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 15000 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 1200 Hz A piston aircraft engine typically rotates at a rate between 2000 rpm and 3000 rpm 33 Hz 50 Hz Computer hard drives typically rotate at 5400 rpm 7200 rpm 90 Hz 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 10000 rpm 15000 rpm 160 Hz 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 4200 rpm or even 3600 rpm spindle speeds 70 Hz or 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 rpm or occasionally 360 rpm a relatively slow 5 Hz 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 90000 rpm 1500 Hz or faster 6 Gas turbine engines rotate at tens of thousands of rpm JetCat model aircraft turbines are capable of over 100000 rpm 1700 Hz with the fastest reaching 165000 rpm 2750 Hz 7 A Flywheel energy storage system works at 60000 rpm 200000 rpm 1 kHz 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 2600 rpm 3000 rpm 43 Hz 50 Hz on 12 V DC power A millisecond pulsar can have near 50000 rpm 833 Hz A turbocharger can reach 290000 rpm 4 8 kHz while 80000 rpm 200000 rpm 1 kHz 3 kHz is common A supercharger can spin at speeds between or as high as 50000 rpm 65000 rpm 833 Hz 1083 Hz Molecular microbiology molecular engines The rotation rates of bacterial flagella have been measured to be 10200 rpm 170 Hz for Salmonella typhimurium 16200 rpm 270 Hz for Escherichia coli and up to 102000 rpm 1700 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 limiter RPM gaugeNotes editReferences 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 1205664419, wikipedia, wiki, book, books, library,
