Brush Friction and Contact Losses

It is apparent from the foregoing that the niceties of adjustment found necessary in obtaining coefficient of friction show the hopelessness of determining the true friction loss by the method outlined in the existing Standardization Rules. It is evident that in measuring brush friction by reading the input to, the machine with brushes up and brushes down there is a great element of error due to the fact that the value of brush friction is such a small percentage of the total input. It would, therefore, seem obvious that the Standardization Rules should be so amended as to allow the determination of brush losses by calculation from data which have been obtained by the most reliable methods and approved by the Institute.