Hydro Turbine Combined Output

The output capabilities of the alternator?

Alternator rated at 94KVA

Are you splitting the effective head pressure when running both? Consequently reducing output on both.

GA from me.

But it really should be a GQ = Good Question!!!!

What is the first turbine driving? You said the second one is driving the 3 phase 400VAC alternator. And what do you mean by "flexible coupling"? Independent pen-stocks, independent tail-stocks, where are they common? Are they running in parallel? What is the load?

The turbines are 2 totally separate installation's next to each other which are identical in design and construction.Their shafts are joined with a flexible coupling to compensate for any miss alignment of the shafts. Turbine 1 drives though turbine 2 to the alternator.

The speed is controlled by an electronic load controller that switches excess power to a bank of geyser elements to keep the speed of the alternator constant, but the actual load is normal domestic and farm equipment.

is the water flow enough for both?

Both turbines have their own penstocks and forebay and are totally independant of each other.

Each turbine consumes +- 2200L/S the flow available is 10000L/S

Is the outlet (exhaust) from the turbines common. Could you be creating some back pressure thus reducing the differential head across these machines when they run in parallel?

Both turbines have separate tailstocks returning the water to the river.

Yes, this is a point to be noted.. Is the same flowrate being used for driving a single turbine and then both of the turbines too? If so, the Force applied on one Turbine when run alone is divided on two turbines thus decreasing the turbine velocity which in the end affects the generated electricity.

Hi,

I didn't understand the mechanical connection you described. How does turbine no. 1 run the alternator, if turbine no. 2 is the one connected to it? What do you mean by flexible coupling among them? Does it mean that turbine 1 drives turbine 2 even if 2 is off?

It seems you're considering both turbines decoupled, when they are not. And combined load, when you drive both at the same time, should be limiting your output.

Hope I have helped.

Perhaps the total system load is only 37.1 KVA. A good way of telling would be if both turbines are load sharing at 18.55 KVA each (providing the governors are set that way). Good luck!

The electronic load controller places full load on the system to maintain the correct speed,therefor the system is running at maximum power at all times.

That's what I mean. I'm assuming you're not operating in parallel with a utility, but powering your own system (frequency control/island mode). What (how much) is the load that you are supplying? Do you have a load control panel with associated circuit breakers? If so you can control your load to see what's happening to the turbine loads by opening and reclosing the circuit bkrs.

The electronic load controller has a bank of 24 x 3KW geyser elements into which it switches all the power the turbines produce so the turbines are always under full load.

If you are producing say 50KVA and the external load is only 20KVA then 30KVA will be switched to the geyser elements.Thus maintaining the correct frequency and speed. As a result the turbines are always under full load regardless of the external draw.Thus the control panel always registers full output all the time.

It almost sounds like your nozzles are diverting water around the turbines to the tailrace when the load is less than the maximum. You mentioned that you can only get 37 kva instead of 50 kva from both units? Is the load (37 kva)equally divided between the two units? I wish I could be more help but I need to understand your system first. Thanks.

I'm just guessing now, but... does the flexible coupling allow 100% of the torque to be transfered to the alternator? As per your description, turbine 1 and turbine 2 are coupled via the drive shaft (?) if the speed of #1 or #2 varies will that not interfere with the torque of the other. I understand the coupling is supposed to compensate for this but if one turbine is turning a little slower than the other isn't it going to end dragging on the faster one? Maybe speed isn't the right term... I understand the speed control set up on these... so more lower torque or less HP on one causes a drag on the higher torque/ HP turbine.

Have any pictures of the set-up?

Yes the coupling transfers 100% torque. The turbines are coupled via their output shafts.The outputs I mentioned earlier where measured at the same speeds. Is it possible an output difference of 0.4KVA could have such an effect?

I have many pics of the installation but cannot seem to get them loaded

Is it possible an output difference of 0.4KVA could have such an effect?

That's what I was getting at. I'm not sure here, but I'd think if the torque on one turbine was less than the other, the one with less torque would drag on the higher one. That is why I'd like to see the design of the flexible coupling. Who designed the turbine set-up? Canyon Industries?

The turbines were designed and built by myself.This is the coupling.

Hmmm. I still think the lower output turbine is dragging on the higher one. With speed controls I'm not sure how this could be tested. Sorry I can't be of more help.

Good luck.