The D5S meter was a slight redesign of the D4S, and the most significant chage was moving the light-load adjuster back to the right side of the frame. A number of other small changes were made to better adapt this model to automated assembly equipment and to improve the meter's operating characteristics. The earlier D5S meters (S/Ns below 76,000,000) had guide bearings on the disk that were of a different material than used in the D4S meters and were prone to premature wear causing serious accuracy errors on light loads.
When ABB bought Westinghouse's meter division in 1990, the ABB logo was phased in gradually, and these later D5S meters have aluminum faces instead of the white faces used since the DS was introduced. |
 Photo by David Dahle |