I don't know how far advanced hydraulically driven alternators have become, they were not particularly clever, they caused more problems than you can imagine........one of the major problems was maintaining correct hertz and voltage values......much of todays electrical equipment requires accurate hertz and and voltage control otherwise electrical motors will continually trip........maybe things have changed with electronic governing........a big problem was in paralleling a diesel driven alternator with an hydraulic motor powered alternator driven by a hydraulic pump, from the main engine.
I will admit that this type or problem occurred quite a few years ago.........as I said, maybe things may have changed.
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TO BE. or NOT TO BE. That is the question!! The Bard
YES THINGS HAVE CHANGED WE CONTROL SPEED AND VOLTAGE THROUGH A REXROTH CONTROL BOX AND IT GIVE US GREAT PERFORMANCE THE GENERATOR IS RUN BY A 32 CC HYDRA MOTOR WE HAVE BEEN USING THIS FOR YEARS IN THE OFFSHORE ENVIROMENT BUT TIMES ARE CHANGING AND DUE TO THE OIL SPILLS WE NEED TO CHANGE TO A ZONE 2 RATED UNIT (ATEX) PEOPLE SEEM TO BE SCARED OF THE WORD ZONE 2 IT'S PROBABLY BECAUSE IT'S NEW TO MOST BUT THE GAS AND OIL WORLD IS MOVING INTO THIS DIRECTION.