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The Development of Land Transport
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The Development of Land Transport
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The Kandó Electric Locomotive
Electric locomotives appeared at the end of the 19th century. However, when operating them, many technical problems
arose which affected the locomotives’ efficiency as well. Neither the DC networks, nor the emerging AC networks of 50 Hz were adequate to operate electric motors. On the other hand, it was very costly to build a separate network for electric locomotives. The solution to these problems was found by one of the engineers of the Hungarian company Ganz, Kálmán Kandó.
Phase converter
Kálmán Kandó’s invention made it possible to operate locomotives effectively
using single-phase 50 Hz AC overhead lines. The advantage of the new system was that it required
only one, relatively thin overhead line, and also switchyards only had to be built at 40 km intervals. In this case
rails served as earthing conductors. The phase converter transformed the single-phase current of the overhead lines
into a three-phase current. Moreover, it was able to control the frequency of the current, adjusting it to the desired power output. The phase converter was one of the most complex electrical devices of that period as it was able to feed the electric power, generated by braking, back into the network. Kandó’s invention is still in use today.
Speed control
The motor had 4 fixed speeds
(25,50, 75 and 100 km/h), and the
train driver could adjust the speed
by way of a liquid rheostat
connected to the traction engine’s
rotor. This system was used only
when accelerating or decelerating as it decreased the locomotive’s efficiency.
Main motor
The locomotive was powered by a 3 m diameter multi-pole asynchronous motor which was placed at the centre of the locomotive.
Pantograph
Countershaft
Oil change sensor
Phase converter
Non-powered wheel
Linked
driving wheels
Kandó triangle
Pushrod
Drive rod
