At the initial stage of development in 1950s, the most dependable technology for the magnet excitation of the operating synchrotron accelerator used flywheel as energy storage device and how effectively this scheme was implemented and utilized has been discussed earlier. In the absence of any alternative for powering magnet excitation, the above scheme was considered as the final and the best design choice at that time. But, the structure of the selected system unfolded few serious bottlenecks during the course of operation of accelerator which were not taken into design consideration earlier due to lack of proper technical inputs and other reasons. The complex scheme of earlier design shown in Fig. 4.1, essentially had two parts: rotating parts—comprising motor–alternator–flywheel and stationary parts comprising—transformers, rectifiers, and magnet systems arranged in tandem for supplying pulsed power to the magnet coil. It was a challenging task to the scientists and technologists during the middle of the twentieth century to ease out from the inherent bottlenecks of mechanical energy storage and pulse power supply and find an alternative method of supplying power for magnet excitation to comply with the various demands from projects experiencing operational difficulties. Magnet power supplies for Nimrod or similar accelerators were designed to operate for long periods with a very high reliability. The plants were designed with minimum life expectancy of 15 years, but due to repetitive exchange of energy between the generators and the magnet coils, the equipment were subjected to high mechanical, thermal, and electrical stresses which ultimately affected the performances. The urgent need of a new concept was purely to avoid the bottlenecks for the reason that earlier system had to work under various restrictions and imposed conditions, some of which are as mentioned below: