This model was developed by Thomas Duncan shortly after his arrival at Fort Wayne Electric Company. This meter is the only model (besides Shallenberger's ampere-hour meter) that uses a fan brake. This model may have been short-lived as arc-lamp systems were starting to give way to series-connected incandescent streetlighting systems at this time.

Another version of this model was built and sold specifically as an ampere-hour meter. The data I have so far indicates it was built very similar to the Shallenberger ampere-hour meter except the coils are side by side instead of front and back. At this time I do not know which model came first.