Hello Clanky,
What was specific to the propulsion of SS Canberra, when compared to a pre-WWII turbo-electric ship? The electric turbo-alternators of another ship drove 3-phase motors coupled to each of the 4 propellers of this liner, the speed reduction being achieved by the number of poles and by the turbine speed.
The younger SS Canberra electric propulsion was indeed certainly much more modern, particularly concerning materials, voltage control, or even electronics.
Which ship was that?
Regards,
Luc
Hi Luc,
Apologies for not replying earlier, I have been travelling a lot recently.
I didn't know that Normandie's propulsion was AC, turbo-electric, I had always thought that Canberra was the first large ship to have AC propulsion, you learn something new every day.
Canberra had 2 main motors, each split into 2 half motors and 2 main turbo alternators. The propulsion could be configured so that one alternator could drive both motors at low speeds (and indeed we often did this).
The motors were started as 3 phase, squirrel cage induction motors and an excitation current was then applied to the rotor so that they ran as synchronous motors.
The turbo alternators were powered by steam from 3 Foster Wheeler ESD type boilers, we used to say that the ship only had 3 steam leaks, number 1 boiler, number 2 boiler and number 3 boiler. We used to walk around the boiler room with a broom handle with a rag tied to it, if the rag suddenly disappeared then you stood very still, used the broom handle to find the steam leak and backed away very carefully.
