| The D2 line of polyphase meters was a slight redesign of the DSP / DAP line of polyphase meters. The most important change was to replace the jewel bearing with a new magnetic bearing that required far less maintenance. Also, the polyester insulation previously used was replaced by butyl rubber on the transformer-rated versions and epoxy-coated current coils on the self-contained versions. The two-part frame was retained but the retarding magnet on the rear part of the frame was eliminated. |