I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

On 01/11/12 23:25, DerbyBorn wrote:
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

yebbut it costs more and river flow generation is lousy on output anyway.

--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On Nov 1, 11:25*pm, DerbyBorn wrote:
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

In days of yore alternators linked to the mains had to be synchronised
and every alterntor runs/ran at exactly the same speed. Power output
is increased not by increasing the speed but by increasing the torque.
As long as the excitation is correct ,it is impossible for the
alternator to run at any other speed once locked in (ie on line)
If the excitation current is too low, the magnetic "bond" can break
and"pole skipping" occurs which can damage the machine.

However these days the output from small altenators is rectified to DC
and then connected to the mains with a special "grid tie inverter".
All these solar PV arrays and most wind turbines have grid tie
inverters.
http://en.wikipedia.org/wiki/Grid_tie_inverter

The advantage is that the plant can be run by non-technical staff and
reliability.
It can be safely left unattended too as everything is fail safe..

Huge grid tie inverters are now available.

In message , The Natural Philosopher
writes
On 01/11/12 23:25, DerbyBorn wrote:
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

yebbut it costs more and river flow generation is lousy on output anyway.

Maybe he meant that at *full* flow the generator would exceed the
designed output and overheat?


--
Tim Lamb

On Nov 2, 8:29*am, Tim Lamb wrote:
In message , The Natural Philosopher
writes

On 01/11/12 23:25, DerbyBorn wrote:
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably..
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

yebbut it costs more and river flow generation is lousy on output anyway..

Maybe he meant that at *full* flow the generator would exceed the
designed output and overheat?



--
Tim Lamb

A major advantage is that the alternator can run at variable speeds
and non synchronous speeds.
Also it overcomes the problem of instabitly in the grid as the
inverter is controlled by the grid rather than vice versa.

The turbine will be sized/set up so it can't overload the alternator
whatever happens.

On 01/11/2012 23:25, DerbyBorn wrote:
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This is balls. But it *was* a Project Manager.

I'm sure you are correct, but the electronics to do this could be hard to
design and may well be not that efficient. It kind of depends on the size of
the power generation I'd imagine.
I also wondered if some form of drive abit like Daf used in their automatic
cars might work.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"DerbyBorn" wrote in message
2.236...
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

Maybe one could have different ways of driving the generator depending on
the flow rate in some way.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Tim Lamb" wrote in message
...
In message , The Natural Philosopher
writes
On 01/11/12 23:25, DerbyBorn wrote:
I was being shown a new hydro plant at our local river a few days ago
(From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

yebbut it costs more and river flow generation is lousy on output anyway.

Maybe he meant that at *full* flow the generator would exceed the designed
output and overheat?


--
Tim Lamb

DerbyBorn expressed precisely :
I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

In the old days, to put a generator (alternator) on line, they would
have to match the speed of the generator to the mains frequency and the
phases. One method used lamps connected between the two sources, to
match them so the lamps went out and stayed out. No difference in volts
between the two, meant that the lamps were out with no flickering,
speed and phases were therefore matched - at which point the generator
to would be connected. Once connected they would stay in sync, output
could then be increased so the unit was exporting power to the grid.

Nowadays, things are very different. It is all done automatically and
smaller generators use inverters feeding units which convert back to AC
with everything matched up.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Thu, 01 Nov 2012 23:25:32 GMT, DerbyBorn
wrote:

I was being shown a new hydro plant at our local river a few days ago (From
the outside) The Project Manager was saying that the speed was finely
regulated by the water flow to give the right frequency. (That was as
technical as he could go on the topic).

This meant that in time of high flow it is throttled back considerably.
Isn't it possible to generate DC and convert it electronically to AC?
Wouldn't this mean that higher speed would give more amps?

Large rotating machinery has a speed limit anyway. There's a capacity
limit to the amount of water/load and the hydro generator should be
matched closely to the water allowed to flow through it - in any case,
the upper sluices and the turbine inlets are sized to only allow this,
with some fine variation as the bloke said.
If you want extra power, you add more units or build bigger ones in
the first place.

On Nov 2, 9:10*am, "Brian Gaff" wrote:
I'm sure you are correct, but the electronics to do this could be *hard to
design and may well be not that efficient. It kind of depends on the size of
the power generation I'd imagine.
I also wondered if some form of *drive abit like Daf used in their automatic
cars might work.

Brian

The electronics is all bog standard off the shelf nowadays. No moving
parts, no maintenance.