Since the end of last year, one of the biggest vertical Induction Hardening Machines has been operated with a power supply of EMA Indutec GmbH. This is a vertical hardening machine for shafts with a diameter of up to 1.000 mm and a length of up to 8 m. The machine was designed by a long-standing customer of EMA - the subcontract heat treatment shop Messrs. TermoIndüksiyon, Istanbul, Turkey - and produced and built on their own. The aim for this investment was to build a vertical, inductive heat treatment machine with minimal distortion of longitudinal shafts for wind energy systems in the immediate vicinity of the manufacturer. So far, the shafts had sometimes to be transported to the United States back and forth for an inductive heat treatment.

A converter of the EMA-type TIV-2D 3k800 was chosen as power supply covering a frequency range of 1 to 3 kHz. With an output power of up to 800 kW, this allows a hardening depth of up to 15mm (depending on the material).

The adaptation of the AC-converter to the provided inductors is carried out via a transformer unit ensuring an operation of one- to three-turn inductors without any problems. In order to minimise the transmission losses on this 8m vertical travel distance, the inductors are directly connected to the outputs of EMA matching transformers moving vertically along and mounted on a solid carrier. The "high-voltage" connection between the transformers and the power source is realised via flexible coaxial cables of corresponding length. The depicted "acceptance-shaft" being hardened has a length of 8 m and a diameter of 395 mm. The material was 42CrMo4 and the achieved hardening depth 10 mm.