Is rpm short for "rotation per MINUTE"?

netmask254 · Post by **netmask254** » Thu Jul 30, 2009 8:32 pm

For very long time, I though 1200rpm means 1200 rotations per second

qviri · Post by **qviri** » Thu Jul 30, 2009 8:57 pm

Rotation or revolution per minute, yes. Divide by 60 to get rotations per second (not a common unit).

dhanson865 · Post by **dhanson865** » Fri Jul 31, 2009 5:56 am

Well it isn't a fan per se but I thought of a Movie Projector and Frames Per Second when reading the original post.

Rotations per second isn't common terminology but frames per second is. Hmm I guess if the frames are on a cylinder such that dozens of frames equals one revolution I'm still off on a tangent.

xan_user · Post by **xan_user** » Fri Jul 31, 2009 7:24 am

I usually hear it as "Revolutions Per Minute."

qviri · Post by **qviri** » Fri Jul 31, 2009 7:43 am

dhanson865 wrote:Well it isn't a fan per se but I thought of a Movie Projector and Frames Per Second when reading the original post.

Rotations per second isn't common terminology but frames per second is. Hmm I guess if the frames are on a cylinder such that dozens of frames equals one revolution I'm still off on a tangent.

If you are looking for a per second unit, radians per second is the SI unit and pretty common. 10 radians per second is approximately a revolution per minute, within 5%.

nd4spdbh · Post by **nd4spdbh** » Wed Aug 12, 2009 9:11 pm

seriously whole thread created for this..... google "define rpm"

swivelguy2 · Post by **swivelguy2** » Thu Aug 13, 2009 4:53 am

qviri wrote:If you are looking for a per second unit, radians per second is the SI unit and pretty common. 10 radians per second is approximately a revolution per minute, within 5%.

That's backwards, 1 radian per second ~= 10 rpm

DAve_M · Post by **DAve_M** » Thu Aug 13, 2009 5:36 am

nd4spdbh wrote: google "define rpm"

You mean "define: RPM"

pcy · Post by **pcy** » Fri Aug 14, 2009 11:57 am

Hi,

No - its revolutions perminute.

A revolution is an angular movement, or rotation, of 360 degrees.

A rotation is an unquantified angular movment.

If the fan stopped and started, and you called each angualr movement (from start to stop) a rotation, then "rotations per minute minute" would be the number of times it stopped and started per minute.

Peter