Power Measurement

  • Ralph Alcock


Power is the rate of doing work. The power output from a tractor can be measured at several locations. The power developed at the power takeoff (PTO) shaft is one location that is commonly used in determining tractor power level. Tests can also be conducted to determine the power output at the drawbar and at the flywheel of the tractor engine. For a given tractor, output power at the PTO will be less than that at the engine flywheel because of power losses in driving the transmission components. Power is also lost at the tire-ground interface, in driving the engine components, as heat to oil and other coolants, and to the exhaust. The maximum measurable power obtainable from an engine is that developed inside the cylinders. This power level is referred to as indicated power (IP).


Torque Output Fuel Flow Shaft Speed Indicate Power Tractive Effort 
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Copyright information

© The AVI Publishing Company, Inc. 1986

Authors and Affiliations

  • Ralph Alcock
    • 1
  1. 1.Agricultural Engineering DepartmentSouth Dakota State UniversityBrookingsUSA

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