Abstract :
The Bureau of Standards has a very complete laboratory for testing dry cells under all conditions encountered in service. The cells are discharged at various rates and for different periods of time and during test are subjected to a wide range of temperature, made possible by the installation of a special refrigerating plant and heating oven. The switches which govern the periods of discharge and recuperation for the batteries are controlled by a master relay operated by a clock. Heretofore only one clock has been employed and no difficulty has been experienced. However, as the apparatus has been used continuously for 2½ years, it was evident that it would soon be necessary to stop the clock for cleaning and adjustment. When the equipment was installed, it was expected that this could be done whenever desirable, but the volume of work has been so great that it has been found necessary to operate the testing plant continuously. Therefore, a second clock has been installed with an automatic device which will throw over the control from one clock to the other in the event of stoppage of either. This places the Bureau´s equipment on a very reliable plane, in line with similar apparatus used by the leading manufacturers.
