FS Class E.333 was a class of electric locomotives of the Ferrovie dello Stato (FS), powered by three-phase alternating current, which were in service from 1923 to 1968. They were designed by Kálmán Kandó for hauling fast passenger trains. Having the same electrical equipment as the FS Class E.552 locomotives, they presented the same defects and had to be modified. After modification, they were able to carry out the services for which they were designed.
Overview
For service on the three-phase AC electrified lines in 1920, FS had locomotives of classes E.550, E.330, E.331 and E.332. All were based on electrical systems designed and patented by foreign companies. The FS Material and Traction Service, wishing to free itself of this burden, independently planned the classes E.551 and E.431. Kálmán Kandó (the designer of the E.550 and the E.330) had had to leave Italy during the First World War and was trying to regain his lost position through the company Ing Nicola Romeo di Saronno, who until then had only built steam locomotives. The first result of this collaboration was the new Class E.552, commissioned by the FS on 17 January 1920, which was intended to replace further orders for Class E.550.
While the E.552 locomotives were under construction, the company Romeo succeeded in obtaining a contract for 18 locomotives for the haulage of passenger trains on flat or moderately steep lines, which was agreed on 17 January 1922 with deliveries scheduled by May 1924. These were to be E.333.001-018. On 4 October 1922, another 22 units were ordered. These were to be E.333.019-028 and 029-040. The Romeo company, which was financially linked to the Mechanical and Naval Workshops of Naples through Credito Italiano, subcontracted to them the construction of the mechanical parts and the responsibility for the whole supply of E.333.029-040.
The locomotives were divided into two subgroups: 001-014 and 029-034 015-028 and 035-040
The second group was distinguished externally by a higher cab other detail differences.
The E.333 was designed to haul both local and non-stop passenger trains of modest weight on moderately steep lines with a maximum speed of 75 km / h in both directions. This implied driving wheels similar to those of the E.330 and a traction system that developed the greatest tractive effort at the two highest speeds. Four speeds were provided and, with a power frequency of 16.7 Hz, these were 25, 37.5, 50 and 75 km / h.
Construction
Mechanical part
The mechanical part of the E.333 resembled that of the E.330, with a UIC wheel arrangement of 1'C1', large driving wheels and Zara bogies at each end. The adhesive weight was reduced from 51 tonnes to 45 tonnes to reduce axle load and allow use on many lines. The overall design of the machine resembled that of the E.552 and other projects developed by Kandó. These included a long section containing the traction motors with their auxiliaries in the centre, the rheostat at one end and the driver's cab at the other. This provision was advantageous for the accessibility of the equipment and for reduction of the accident risk for train drivers in the event of an explosion of the rheostat (which occurred several times on machines of various classes, with sometimes deadly consequences).
Electrical part
The electrical part of the E.333 was substantially similar to that of the FS E.552 locomotives. The only notable differences were the presence of cooling fans for the traction motors and a smaller number of rheostat electrodes. The two traction motors were identical to those of the E.552, with an output of 800 kW at 75 km / h for each. Foreign patents were not completely eliminated. The stators were wound according to a Kandó patent and the rotors according to a patent by Ottó Titusz Bláthy, one of Kandó's colleagues at Ganz. As with all the locomotives designed by Kandó, the regulation of starting and the transition from one speed to the next was done by an automatically controlled liquid rheostat containing sodium carbonate solution. Four fixed speeds were available by switching between 12 and 8 poles on the motors and using cascade or parallel connections. The fixed speeds were: