SHAFT-DRIVE IDLER 1179712 - Caterpillar

The ratings must be reduced in order to accommodate changes in the altitude. The ratings must be reduced according to the data for derating that is obtained from the test specification for the engine.All of the ratings that are defined have a manufacturing tolerance of three percent.Use the following guidelines in order to determine the applicable engine rating.
Operating an engine at a greater power output than the engine is rated for will reduce the service life of the engine before overhaul.
"IND A (Continuous)" - This rating allows operation at the engine's rated load and speed for 100 percent of the time without interruption or load cycling. The engine may be operated at full load for 100 percent of the duty cycle. The following applications are typical: pipeline pumping, ventilation and applications that are specified by the customer."IND B" - This rating is for service with power and/or speed that is cyclic. Full load operation must not exceed 80 percent of the duty cycle. The following applications are typical: irrigation with a normal pump demand that is 85 percent of the engine rating, mechanical pumping and/or drilling in an oil field and stationary plant air compressors."IND C (Intermittent)" - This rating is for service with power and/or speed that is cyclic. The engine can be operated continuously for one hour at the "C" rating. This is followed by one hour of operation at the "A" rating or below the "A" rating. Continuous power may be supplied by engines with the "C" rating. However, operation at full load must not exceed 50 percent of the duty cycle. The following applications are typical: agricultural tractors, harvesters, combines, off-highway trucks, power for fire pumps, drilling for blast holes, rock crushers with high torque rise, wood chippers with high torque rise and oil field hoisting.