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Dual driven generator 1

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Guardiano

Electrical
Nov 11, 2008
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Dear Forum members,
We are working on a preliminary phase of a project which will include a 10 MW alternator driven by a steam turbine. The turbine will operate only for six months of the year and power will be supplied through a diesel driven generator for the remaining six months of the year. Somebody suggested a common 10 MW generator driven on one side of the shaft by a steam turbine and the other side by a diesel engine. Anyone who has seen a similar arrangement.
Kind regards,.
Guardiano
 
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The advantages: Avoid the cost of a second alternator.
The disadvantages: Add the cost of clutches and gear boxes. Consider additional failure points and no back-up system.

Bill
--------------------
"Why not the best?"
Jimmy Carter
 
A 10MW diesel is almost certainly going to be a low speed engine and likely coupled to a salient pole generator. A turbine is typically a high speed machine with a turbo-alternator. It's almost certainly going to be easier to provide a reduction gearbox for the turbine than provide a speed increase for the diesel, but the salient pole generator will be a big lump.
 
Not unknown with gas turbines and a.c. generators

Have a clutch between turbine and generator. think of it like a bicycle freewheel, when the turbine powers the generator, the generator runs and synchronises to the grid.

Power down the turbine and the generator runs on and can provide Var to the grid.

Whenever you want power, just start the turbine.

Larger units have a turbine at each end of the generator and two clutches.

What you want is a turbine at one end and a diesel engine at the other.

Technically possible, but the mechanical design can be complex, keeping all the alignments correct can be an engineering challenge.

For suitable clutches see
Commonly used on naval ships where you have different engine types for cruise and sprint.

Downside, as I said above, can be more complex than it seems. Not for the faint hearted!
 
Thanks Hoxton. That was useful info.

As for as maintenance goes, the generator requires the least, especially if it is closed circuit cooling. Both the engine and turbine require more time based (and much more costlier) maintenance than the generator.

Muthu
 
But, can you service one of the prime movers safely while the other is running?
Is a clutch between the diesel you're wrenching on and the spinning generator absolutely reliable?

It may not matter that you save on a generator if you can't really service one of the prime movers while the system is running.

Keith Cress
kcress -
 
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