Commemorative stamp series - Germany / German Democratic Republic 1974 - 10 Pfennig

Leipziger Spring Fair 1974 At the Leipzig Spring Fair 1974, the Ministry of Posts and Telecommunications of the German Democratic Republic issued two multicolored special postage stamps. Leipzig Spring Fair 1974 10-pfennig value: VEM - high-voltage testing system The VEB transformer and X-ray machine "Hermann Matern", Dresden / DDR has been manufacturing for over a quarter of a century, among others. Installations and equipment for testing and measuring the dielectric strength of electrical equipment, machines, cables and insulating materials in the industrial and research fields of electrical engineering, in particular high and ultra-high voltage engineering. High-voltage test systems of all types of voltage are manufactured in this large Dresden factory. The VEB transformer and X-ray plant is one of the most prominent producers of our continent in this field; its products are exported to four continents and have proven their top class there. The special postage stamp shows a DC voltage test system for 2MV / 100 mA. The transmission of electrical energy with high DC voltages is gaining more and more importance at present and in the future, because in the transport of large power over long distances thereby technical and economic advantages over the AC transmission can be achieved. For the testing of components of high-voltage direct current transmission very high DC voltages are required and consequently also test systems that can generate such high voltages. For this reason, a series of DC voltage test systems with rated voltages of 1,200 kV to 2,000 kV and rated currents in the range 10.0 ... 500 mA has been developed, built and tested in the VEB Transformatoren- und Röntgenwerk. These systems (about 15 m high) are designed for the first time in the world in a novel single-phase two-way circuit, whereby even at high Beiastung low voltage drops and a very small ripple of the output voltage can be achieved. These test systems are intended for stationary installation in buildings. They consist of a multiplier device in open multi-column design, which is fed by a 500 Hz medium frequency converter via a transformer unit. With a built-in the multiplier high-voltage measuring divider, the measurement of the high voltage is made. The rectifiers are equipped with silicon diodes. The switching of the polarity of the DC voltage supplied erfoIgt from the control table electro-hydraulically by pivoting the rectifier within a few seconds. External damping resistors are not required for the operation of the system. When coupled with other test equipment, the DC test systems are also suitable for generating mixed voltages.