Proven 6kw Turbine performance decreasing

[Robert Jurs]

I went out and tried to do a connection test across the tower and the ground wire going up to the turbine, and there IS indeed a connection, so my guess is that ground wire is connected to the tower base, where the other wires goes to the slip rings at the top of the tower.

However there was some kind of "signal" noise in the tone/sound that the multimeter does to indicate connection between the two measuring points.
I don know if this could indicate a loose ground connection? Or if this matter at all.

If I understand the schematics correctly I dont think it uses the ground wire for anything. Other that standard safety reasons. Or am I wrong?

[Alan D]

The cable in the control panel. Brown / Black / Grey / Blue. Goes directly from the control panel up inside the shaft to the slip rings with no junction box.
If so the Blue / Earth is not connected to the turbine.
The turbine is still up. ?.  
You have no access to the slip rings for testing / visual inspection.
Because there is no earth connection between the turbine and the panel. ( Why ?   )
For testing the winding insulation resistance. You need to run a single core cable from the turbine tower / earth connection to a location next to the control panel.
With the meter on the 2000K range not connected what does it display.
With the meter on the 2000K range connect one meter lead to the single core cable ( connected to the turbine tower earth connection ) and the other to any of the three ( Grey / Black / Brown ) What does it display.
If you cant check the slip rings / brushes visually for erosion / pitting / wear / burning the electrical readings are a bit iffy
The readings taken on the 200 Ohmn range between the ( Grey / Black ) ( Grey / Brown ) (Brown / Black ) Should be the same and not moving about. 12 Ohms ish.
When the meter is on 200 Ohmn and not connected. Does it display the same at all times.
The slightest blade movement ( couple mm backwards / forwards ) would generate a voltage which would make the Ohms readings false.

Ref " I also made the same measurements at the base of the turbine tower, and they were more or less the same, with fluctuations, in the same ranges. "

This cable must go from the control box to a box / isolator at the base of the turbine tower. What does the Blue / geen/yellow tape cable do in this junction box. ?
Is there another cable going from this to the turbine tower earth connection.

[Robert Jurs]

Yeah. The turbine is still up so I don't have direct access to inspect the slip rings. But we will take it down later this summer, at that point I will do the check, and tests
I will do the test, with running a ground cable from the turbine generator to the control box. And measure across to the 3 phases again.
Hopefully this will give some useful results.

I just wanted to know if there was anything I could do now, without taking it down.


As for your other questions - here are the answers:

There is a junction box inside tower base, however, it is just connecting the 4 wire cable from control box, 1-to-1 to another 4 wire cable that goes to up the tower to the turbine top. But my guess is that the ground is terminated/connected to the tower, before going to the slip rings.

My multimeter at 2000k Ohms not connected it shows 004
When connected across blue/ground to one of the 3 wires there is no change = still 004

Multimeter at 200 Ohms range and not connected, it starts at around 38.6 and it slowly goes down in 0.1 steps. Until it settles at around 32.0 after 5mins.

Turbine wings are totally fixed. With a break activated on the axel of the blades. So I don't think it can move at all. It looks and sounds totally static.

I guess the green/yellow tape in the control box, just indicates that they used the blue wire for ground

In the junction box in tower base, cables "changes" color like this:

From box -> Turbine
Brown -> Black
Black -> Black
Grey -> Black
Blue -> Green/yellow

The Green/yellow wire in junction box goes directly into the 4 wire cable (black/black/black/green-yellow) that goes to the top of the tower.
There is no other connections in the junction box. Only these 4 wires straight through.

There is no other cabled between control panel and the turbine.

[Alan D]

Ref : " In the junction box in tower base, cables "changes" color like this:

From box -> Turbine
Brown -> Black
Black -> Black
Grey -> Black
Blue -> Green/yellow

The Green/yellow wire in junction box goes directly into the 4 wire cable (black/black/black/green-yellow) that goes to the top of the tower.
There is no other connections in the junction box. Only these 4 wires straight through. "


The three black cables going up to the top would be directly connected to the terminals on the  top of the slip rings. There is no other connections.
The Earth cable can not be connected to the metal work because it would get ripped off as the turbine rotates.

Unless the Earth cable is terminated inside the vertical tube that the cable / brake rope goes to the top in.
Reading the installation manual it does not mention Earth connection to be made at slip ring internal assembly.

[biff]

Maybe the metal tower is the ground earth ,
      Maybe.
       Biff

[Alan D]

If there is no movement at all on the rotor ( Turbine not producing a small voltage ) it sounds like your test meter is not to good.
If I wired a 12 volt tungsten bulb across my test meters when testing on Ohms It would give a stable constant reading.
If I wired a 12 volt tungsten bulb across any two phases of my turbine when it had stopped. Then turned the rotor 10 deg the bulb would blow.
( very small movement produces a voltage. )
For Ohms / MOhms testing there must be zero volts.
If you test at the base of the tower junction box from any black cable to a good metal part of the tower with your meter on 200K
The meter should display the same reading with it turned on.
And the red and black probes are open circuit. ( Not connected )
And the red or black probes are connected to any black cable and to a good metal part of the tower. (not galvanised. scrape a line into the tower with a small hacksaw )
The display reading should be constant.

[Robert Jurs]

Thank you all for all the help up until now. Your quick and useful suggestions have given me a lot more insight, in how my setup is working 

I agree that it sounds like my test device, might not be working properly. So I think it is time to get it replaced.

The turbine is now back in service, so I can't do any more testing right now. However I will get a new and proff multimeter soon. And we will take the turbine down for service later this summer, at that point I will test as suggested, and also test and check the slip rings.

I will let you know about the progress.

[Alan D]

In the control panel there are two Schneider 24 volt D.C. three phase contactors.
One contactor is energised to feed three phase turbine supply to three phase bridge rectifier that feeds the 6 K.W. Windy Boy.
The other contactor is energised to feed three phase turbine supply to three phase bridge rectifier that feeds the dump load.

Where does the 24 volt D.C. supply come from that energises the contactors. ?

Only the one contactor is energised while the turbine is running feeding the Windy Boy.  ? The other one should not be energised.

Is there any carbon / burnt smell near the contactors.

By Design I would have expected the three phase bridge rectifiers to have been mounted onto an aluminium heat sink. They look like they are just mounted onto the internal metal side of the control panel. ? If its been working for years that's O.K. just about.

[Robert Jurs]

Very nice to know how this is actually supposed to work All the different components are starting to make sense to me now. Thank you for explaining.

To answer your questions:

Regarding 24V power to contactors. There is a built in controller board, with a powers supply in the left side of the box.
This feeds the contactors.



Regarding the rectifiers, you are correct they are indeed mounted to an external heat sink. It did just not show on the previous pictures.
But there you can see it on the outside of the box:



Also there is now noticeable burnt smell inside the box. 

And I have now observed the workings of this box for some time.
I can confirm that the contactors does indeed switch back and fourth between them. At the time of observation (10 mins ago) wind speed is very low, and the turbine generates between 0 and some 400watts. So I assume the controller board switches of turbine->Inverter when the turbine does not generate enough power to active the inverter.
And then when it is rpm up it switches back to turbine->inverter. Which explains the contactors switching back and forth between the two.

[heatherhopper]

Robert
Good to see you are making some progress and I hope you will keep us informed through to a result (good or not). We all learn a bit if a thread plays out. There is another similar(ish) recent thread you may find interesting here:
https://www.navitron.org.uk/forum/index.php/topic,31818.0.html

I appreciate you have been measuring all sorts of things and I'm not sure what you have determined thus far about AC delivery from the Turbine but the wind interface (rectifier etc) seems a bit suspicious even if the AC delivery is not right.

By way of some background you may not be aware of. There were various problems with these turbines around the time yours was installed often related to the Proven wind interface (the rectifier etc). Coincidently SMA were warning about inadequate over-voltage protection for their Windyboys and produced their own, good but expensive, solution - presumably following some destructive events and warranty claims. Seems a number of different interfaces were devised/installed before the problems abated.
The interface usually just needs to provide simple AC-DC rectification and overvoltage protection, via a dump load, for the Inverter. Yours seems an odd and over-complicated configuration and certainly not the basic Proven issue I have seen.

The "switching" of the contactors you have described does not make any sense and I can see no logic for the dump to operate at all on low voltage. You said previously you had not seen the dump load operating. Are you sure it has not been doing so at times you would have expected higher output? The dump load only needs to be activated to protect the Inverter from very high voltages and is usually set somewhere a little less than the max 600v. The Turbine itself can run quite happily, although noisily,  unloaded. For a grid-tie system I imagine activation would only happen occasionally in high winds and only for any sustained period if the Inverter could not synchronise with the grid since the grid provides a permanently available load. If you have some information about the interface (schematics, manual, controller type, dump resistor size etc) that would be interesting.