Round Type (1897 to 1903)	Back	Up	Next
Shallenberger's 'integrating wattmeter' met the industry need for a watthour meter, but it was too heavy and expensive. Since he was too ill to do any further work, two other engineers (H. P. Davis and Frank Conrad) were selected to design a lightweight and cheap watthour meter, and their result was known as the Round Type meter. This meter was much lighter at only 12 pounds, and introduced several features that are still in use today on modern meters: lightweight disk, small air gaps, power factor adjustment, and separate covers for the movement and terminals. This meter is quite distinctive with its 5-dial watthour register and terminal chamber located on the back of this meter. The light load adjustment on this model was unique as it involved varying the voltage supplied to the voltage coils. The Round Type meter was the last model made by Westinghouse to use the pivot-type bearing, a new ball bearing being introduced on the following Type A.

Electrical Meterman's Handbook

Northeast Utilities collection

Photo by Glenn Grabinsky