In 1842, Christian Andreas Doppler (1803-1853) made the equation about frequency
and relative movement of sound source and observer. To prove his theory, he
conducted a unique experiment. For two days, Doppler had a train pull at different
speeds a freight car with trumpeters playing on top of it. He then had a musician
record the height of the notes played as the train moved closer or further
away. This effect proved Doppler's theory superbly.
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The transformer combines the functions
of pump and a motor in one design. Therefore the transformer port plate
has three ports instead of two. One is connected to the high pressure
lin, the motoring kidney. This kidney delivers the power when a load requires
flow with a certain pressure. A second kidney is connected to the load.
The third is connected to the low pressure line. The power which has to
be delivered to the load is controlled by turning the port plate around
its axis. Turning the port plate changes the surface of the motoring kidney
which is connected to the high pressure rail. When the surface increases
enough the transformer starts turning and will deliver flow to the load. |
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