Rated Speed?

[JCyrbok]

Been doing alot of reading in my ISB and DC shop manuels about our engine and trucks. One term that I am having confusion about is "Rated Speed". They use this alot when dealing with oil and fuel pressures such as; "Minimun oil pressure of 45psi at rated speed. "



WHat is "Rated Speed?" Is that RPM redline or something else?



Whould like to know so I can tell is my oil and fuel pressures are with in spec.



Thanks

J-

 

[illflem]

Rated speed is the normal operating rpm, on your rig 2000 rpm is close enough.

 

[JCyrbok]

thnxs

Thanks Illflem u come through again with the answer!!!



J-

 

[Ncostello]

Interesting. My service manual describes pedal to the floor, no load, governed full throttle as simply... high idle. I know they're rated for this... but I cringe at the thought. However, I've driven the local dodge dealers Indy 500 Official tow truck (early 90's model CTD) and the operator told me to give it full throttle in neutral. Sure enough it went to its governed RPM and actually sounded right at home there. I'm not so sure about what my 24V would sound like.



I always figured Rated speed would be the "high idle" also.

 

[A Johnson]

Rated speed is the RPM where the Horespower is measured. The high idle may be (and usually is)different due to governor droop, for drivability reasons.



Rated speeds vary due to different RPM requirements of different machines, pumps vs generator vs automotive etc. . You could have a 230hp @ 2700 or a 230@ 2500 the rated speeds are 2500 and 2700, yet the hp rating is the same, you will have more torque with the 2500 rpm rating, you have to, to achieve the horespower at the lower RPM.



Hope this helps.



A Johnson

 

[rbattelle]

In the gas turbine industry we usually take rated speed to mean maximum safe continuous RPM. I had assumed the term meant the same thing here.



But Johnsons argument seems pretty sane.

 

[illflem]

Without getting technical about it, for JCyrbok's original question as far a checking fuel and oil pressures 2k rpm is fine.