Kandó, Kálmán

(Pest, July 8th, 1869 – Budapest, January 13th. 1931)

He studied at the Teacher Training Secondary School, the so-called Model Grammar School of Péter Pázmány University of sciences and he graduated from the Faculty of Mechanical Engineering at the Technical University Web link of Budapest.

He joined the Paris Compagnie de Fives – Lille factory and worked in the eletro-technical division. It is here that he became acquainted with the theory and design of two and three-phase induction (asynchronous) motors operating on the rotating magnetic field principle.

Invited by András Mechwart, the general manager of the Ganz Factories Group, he returned home in 1898 and, under his leadership, the experiments relating to the first series of three-phase motors were started. As a result of this, the first example of the F series was completed in 1895.

It is in 1896 that, by using a 1000 mm gauge test track, the experiments with a 500 V, 15 Hz two-phase electric carriage started. These experiments determined the activity of technical historical importance that Kandó performed in the field of AC railway traction.

At that time, no electric traction existed suitable for the standard-gauge railways that were exclusively steam operated, due to the lack of an electric locomotive operating at a voltage significantly higher than that used then. It was Kálmán Kandó who created a locomotive of this type first. Based on the plans developed under the leadership of and using the calculations performed by Kandó, the Ganz Factory undertook the electrification of the 106 km Valtellina railway in North-Italy between 1898 and 1902. The success rested on the selection of the line voltage of 3000 V, which was significantly (4 to 5 times) higher than that used earlier. However, such a high voltage required electric motors and switching devices of proper design; indeed, the successful electrification of the Valtellina railway was based on the technical solutions of these new structural elements.

The favourable traction results of the locomotives planned by Kandó lay in the excellent parameters of the motors calculated by him. In fact, he selected the dimensions and utilised the active materials in a manner that, due to the high saturation of iron cores and the low magnetic leakage, the motors were less sensitive to the line voltage variations and, as a result of the high short-circuit current, they were capable of exerting high torque.

Incited by the success achieved with the Valtellina railway, the Italian Government established the factory named Societa Italiana Westinghouse in 1905, and invited Kandó to undertake the management of this factory and the planning of the three-phase locomotives. His activity in Italy resulted in the development of a series of locomotives used for freight trains and mountain passenger trains.

In spring 1915, Kandó returned home and occupied a post at the railway department of the general staff in Vienna. It is here that he formulated the basic principle, since then world-wide accepted, that the electrification of standard-gauge railways is reasonable only if they can be connected, by means of simple transformer substations, directly to the standardised frequency national power system.

The last results obtained by Kandó were the electric locomotives provided with frequency converters, put in service in 1928.

Memberships: Honorary doctor of the József Technical University (1922), member of the Upper House of Parliament (1927), correspondent member of the Hungarian Academy of Sciences (1927).

Honours: Wahrmann-prize, Corvin Wreath, Order of the Italian Crown.