40 Kw. 3 phase Alternator much too noisy

Dec 29, 2017 4 Replies

Evening all.



In my workshop I have a Lister 4 cylinder diesel, air cooled 3 phase Altern ator I think it must only have two poles as to get 50 Hz it seems to run fa r too fast and makes far too much noise in so doing.



It is at least twice as powerful as I would ever need and I often use it at about half revs at which speed it still generates enough to run an old Mil ling machine, However It would be very nice it I could run the diesel at t his low speed and still get 50 c/s and the correct voltages. It is skid mo unted, bolted to the floor on a heavy chassis but the engine and alt. are c lose coupled. I was toying with the idea of separating them and hooking up a chain shaft drive behind the set to gear the motor speed down by at least half.



This will be a big job I fear, as they are very close together and it might be necessary to move the engine to the right a bit to enable sprockets or even pulleys to be connected to gear down the alternator. Has anyone ever done this and has anyone any simpler lateral solution.



Or - alternately does anyone wish to swap a noisy 40 Kw set for a nice quie t 15- 20 Kw set ?


In message , George writes

No help to you George but I am reminded of an ingenious set up used to provide a range of speeds on a flat belt drive centre lathe.......a car gearbox, directly driven from the motor, with a flat drive pulley instead of the prop shaft drive:-)

Not used in a production environment of course!

rnator I think it must only have two poles as to get 50 Hz it seems to run far too fast and makes far too much noise in so doing.

at about half revs at which speed it still generates enough to run an old M illing machine, However It would be very nice it I could run the diesel at this low speed and still get 50 c/s and the correct voltages. It is skid mounted, bolted to the floor on a heavy chassis but the engine and alt. are close coupled. I was toying with the idea of separating them and hooking u p a chain shaft drive behind the set to gear the motor speed down by at lea st half.

ht be necessary to move the engine to the right a bit to enable sprockets o r even pulleys to be connected to gear down the alternator. Has anyone eve r done this and has anyone any simpler lateral solution.

iet 15- 20 Kw set ?

How about sourcing a four pole alternator?

a car gearbox would need its output to the engine, input to alternator.

Quiet generators are rather costly things. ;-)

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