PREDICTION OF REPAIR AND MAINTENANCE COSTS OF FARM TRACTORS BY USING OF PREVENTIVE MAINTENANCE

Estimates of tractor repair and maintenance costs are important for farm machinery replacementdecisions and for general farm budgeting. The aim of this study was to provide a statistical analysis for the repairand maintenance costs of tractors in order to present an appropriate mathematical model based on farm recordsand to compare the derived repair cost function with other estimates. The study was also regarded as anexploratory exercise to assess the feasibility and form of a more comprehensive study on the using of PM inagriculture projects. In this context a study was conducted to predict accumulated R&M costs of three typicaltractors namely JD-3140, MF-285 and JD-3350 based on total working hours (X) by using Preventive MaintenanceProgram (PMP) in Kavardeh Agribusiness Company in Iran. To present the model, the stratified random samplingmethod on the basis of tractor age per year was used. The mean accumulated repair and maintenance costs andalso the mean working hours (h/year) were calculated for per class separately. Calculated data was analyzed onthe five models, linear, logarithmic, polynomial, power and exponential. Finally, it was found that power modelgave better cost prediction with higher confidence and less variation than other models.