Sangamo Type H electric meter, 1911
Click on the image to zoom. Click and drag your mouse over the image to move it left or right. Use the small navigation window to select the area you wish to zoom on.
Purchase a reproduction of this item on VintageMaineImages.com.
This model had been in development for some time before its introduction in 1911, but Sangamo had to wait for the Tesla patents, owned by Westinghouse, to expire.
This induction-type meter uses fluctuations in magnetic fields to turn the rotating disk, while a drag, or lag, magnet keeps the disk turning at a rate proportional to the current.