Abstract: Converter modules have a busbar system for a plurality of power semiconductor switches or, preferably, IGBT power semiconductor modules (IPMs). The power semiconductor switches are arranged in pairs, facing one another or facing away from one another, close together and parallel. In accordance with exemplary embodiments, alternating current is fed in one or two phases via bridge circuits composed of two or four power semiconductor switches.

Abstract: A photographic copying apparatus has a DX code reader for reading a DX code or identification code on negative film, a film scanner for acquiring density information of the negative film, and an exposure station for exposing printing paper. The exposure station is controlled based on exposure information derived from conversion information selected with reference to the identification and density information. A reference film is test-coped for correction purposes, and conversion information for plural types of film is corrected based on density of the test copy and density of the reference film measured by the film scanner.

Abstract: Tool turret for a machine tool, the turret head of which is designed to be equipped with drivable tools, wherein for shortening the times required for indexing the rotatable turret head a three-part HIRTH tooth system is used to lock the turret head and a coupling which is constructed such that it can be disengaged by rotation of the turret head is provided between a drive shaft of the tool turret and a tool spindle of a drivable tool.