# Electro-Hydraulic control resources



## Going_Commando (Oct 1, 2011)

Wanted to add this picture to show you want I am dealing with. Babylon translator is getting a workout on my phone. :laughing:


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## wildleg (Apr 12, 2009)

interesting stuff.

while you are figuring this stuff out, try to get your company to fork out for some trips to Packer's games, or maybe to Germany for Oktoberfest later in the year, under the guise of learning the language haha.

lets see some pics of the controls !


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## Going_Commando (Oct 1, 2011)

wildleg said:


> interesting stuff.
> 
> while you are figuring this stuff out, try to get your company to fork out for some trips to Packer's games, or maybe to Germany for Oktoberfest later in the year, under the guise of learning the language haha.
> 
> lets see some pics of the controls !


That would be nice. Its owned by a municipality, so I don't see that happening. Here I am staying busy waiting for my boss to get parts.



ETA: took a bunch of pics but I'm on my phone. Will upload when I get home.


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## gnuuser (Jan 13, 2013)

the 2 biggest weaknesses with hydraulic control systems are leakage and air
cavitation in the hydraulic fluid caused by excessive turbulence can leave air bubbles in the high points in the system and decrease the efficiency of operation.
leakage usually caused by seals wearing out due to heat, contamination, and in some cases seal deterioration from using the wrong fluid type.

if the pressure is jacked up in the system then its either air or an attempt to make it run with the leaking conditions.
over pressure conditions can indeed cause leakage.

all in all hydraulic control systems are reliable and usually have a long life span.

in any event though you have a real mess on your hands to deal with


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## Big John (May 23, 2010)

I don't have any good resources. My MO was always to test all the electrical components in the system to be sure they were operating right, and after that, I could safely say "Yep, it's a hydraulic problem!" and you can often figure out where just by determining what limits aren't pulling in.


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## Going_Commando (Oct 1, 2011)

Big John said:


> I don't have any good resources. My MO was always to test all the electrical components in the system to be sure they were operating right, and after that, I could safely say "Yep, it's a hydraulic problem!" and you can often figure out where just by determining what limits aren't pulling in.


Should have taken pictures of the sludge that was packed into the filter. Apparently the boss man hasn't changed the filter in 8 years. System is probably looooooaaaded with sludge.


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## Wirenuting (Sep 12, 2010)

Wish I could get my hands on it, been years since I worked electro-hydraulics. I spent 22 weeks @ 12 hours a day learning it for the navy back in 86. 

Change the fluid, filter and flush it out.. Take your time drawing it out and you'll see how easy it is.. 

I'll look up a book left over from back then to get a company name for training.


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## Big John (May 23, 2010)

Wirenuting said:


> ...Take your time drawing it out and you'll see how easy it is....


 I've always said electricians were well suited to it. The schematics are similar to control diagrams. Think of pilot pressure as low-voltage.


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## Wirenuting (Sep 12, 2010)

Big John said:


> I've always said electricians were well suited to it. The schematics are similar to control diagrams. Think of pilot pressure as low-voltage.


Back then it was mostly Transistor logic for control of the gun mount. Funny how fast that equipment operated and it was more reliable then the new fangled digital controls that were out. 

Control work boiled down to a simple concept, "Every control circuit component was on or off".


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## Going_Commando (Oct 1, 2011)

Picasaurus-Rex:

Control cabinet outside:


Inside:





Hydraulic Pump Solenoid valves. Don't mind the rags. :whistling2:


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## Going_Commando (Oct 1, 2011)

Generator Cabinet with protective relays:


Breaker to tie generator to grid:


Original generator setup, kept as spare parts for whatever reason, with a rotary exciter behind it:



Ossberger turbine. Horizontal setup, generator is a 600kW with a 1.5 service factor. Don't mind the mess, we just did annual maintenance a little while ago and still haven't cleaned everything up yet :laughing::


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## Big John (May 23, 2010)

Neat. Except for whenever I see those stupid square gauges I know troubleshooting likely just got to be that much more of a pain in the ass.

Just finished rebuilding one of those DB-15 breakers not long ago. I like Westinghouse a lot. Those plus the old GEs are workhorses if maintained.

What are you using the one Basler for?


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## Going_Commando (Oct 1, 2011)

Big John said:


> Neat. Except for whenever I see those stupid square gauges I know troubleshooting likely just got to be that much more of a pain in the ass.
> 
> Just finished rebuilding one of those DB-15 breakers not long ago. I like Westinghouse a lot. Those plus the old GEs are workhorses if maintained.
> 
> What are you using the one Basler for?


Honestly, I don't remember. I'd have to read the faceplate of it. :laughing:. I've only been in the plant like 4 or 5 days in the past 6 months. I was doing daily checks for a while, but now I am more of an extra hand, troubleshooter, that type of thing. I haven't done the day to day stuff since before I moved to California, so I am a bit rusty what all the protective relays and such do. I've got my work cut out for me now though, especially since getting this crap working again is going to be a spare time, nights and weekends gig. We also have to rebuild one side of the tailrace this summer, and a bunch of other work, so I am going to be one busy mofo at some point. I might be over there tomorrow, and if I am I will find out what the Basler is for. Reverse power maybe?

Funny thing about that breaker. A few years ago, a mouse made a nest in between the contacts when we were offline for the winter. That spring we got everything going, didn't check the breaker, and it went BANG when we hit the contact close button (manual sync). We ended up ordering all new contacts and such, rebuilt the breaker, and got it going again. Then, while we were doing some cleaning last summer, I asked the bossman what the wooden crate was for next to they hydraulics control cabinet. He said, "I've been here for 15 years, and I don't have a clue." Lo and behold, we pop the top off the crate and it is a brand new Westinghouse breaker. :laughing:


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## wildleg (Apr 12, 2009)

forget all that other stuff. just get the stargate working so you can hunt down some alien booty


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## Semi-Ret Electrician (Nov 10, 2011)

Flush system,change filters, refill, bleed off air. It will run forever.

Type German into a translation program to get English out.:thumbsup:


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## Nuzzie (Jan 11, 2012)

What's the deal with someone manually opening and closing the wicket gates? Someone manned there all the time to adjust them for load changes? That must be inefficient. Then again, that's how they used to do it...

Wait handpump? Wouldn't your frequency on that machine be all over the show? Surely that couldn't be fast enough :S


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## Big John (May 23, 2010)

Nuzzie said:


> ...Wait handpump? Wouldn't your frequency on that machine be all over the show? Surely that couldn't be fast enough :S


 If he's feeding the grid then his frequency and voltage are fixed by the infinite bus. The governor just changes his power output.


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## Going_Commando (Oct 1, 2011)

Big John said:


> If he's feeding the grid then his frequency and voltage are fixed by the infinite bus. The governor just changes his power output.


Yup.

Basically, we base the output of the generator on the amount of river flow available. This plant is ~400 yards downstream from a lake, which has gates at the outlet, so we (in coordination with the state) set the out flow of the lake based on lake level and expected precipitation forcasts. Based on how much water is flowing out from the lake, we figure out how much we need spilling over the flashboards (plywood held in place by 1" schedule 40 pipes, will describe purpose later) at the dam (usually ~15-20 cubic feet/second) to keep the river level normal between the dam and the tail race (outlet) of the powerhouse. So, right now we are running at about 400kW, so that is roughly 100-120 cfs flowing through the turbines (iirc), with about another 20 or so cfs flowing over the dam (at lower river flows like now), which puts us at about 140-150 cfs going down the river. There are small streams and such that fill the river between the dam and the powerhouse, so aquatic life is not affected by generation, and to keep things looking pretty for the tourists. 

At higher flows, say during spring runoff, where there is a much larger volume of water flowing into the lake, river flow will be greater. If I remember correctly, our plant at full power (rated 600kW, but we run about 680-700kW at full power due to service factor) will pull about 150 CFS of water through the turbine. I've seen 700 CFS flowing out of the lake, which means we have to open an additional waste gate, and drop the flashboards to allow a greater volume of water to flow over the dam without bypassing it (very very bad :laughing. This is all a careful balancing act between keeping the lake from flooding the surrounding area, the plant making $$, and keeping the river flowing appropriately so wildlife isn't effected.

Flashboards (plywood held in place by pipes) are designed to raise the level of the pond to give the plant higher head. Head, in water terms, is the distance between the top of the mill pond to the turbine. This difference in height is what gives the hydraulic pressure necessary to spin the turbine and generate power. The head at this plant is 76' iirc, and the water flows from the dam to the turbine in 2 4' penstocks (pipes, basically). During normal operation the flashboards are in place at the top of the dam, giving us that extra bit of water pressure. During times of high flows, we pull the flashboards before increasing output from the lake, but sometimes there is just too much water pushing against them to remove them. When enough water is pressing against them, the 1" schedule 40 black iron pipes will fold over, the plywood will go down stream, and the dam will then allow a significantly higher volume of water flow over it without over-topping the embankments. 

This is all a pretty slow process. River flow is usually pretty consistent except with heavy rains, spring run off, and fall draw down (lowering the lake level in preparation for winter to allow for more room for water in the spring). It's not like the river flow is changing by the minute. We have been at roughly the same river flow for the past month and a 1/2, but once the snow starts melting and flowing into the lake, the output will increase. When we have heavy, saturated, snow like we have now, a good portion of that will not be absorbed by the ground (considering the ground stays frozen longer than the snow), so it will flow into the lake and cause it to rise a few inches a day. Right now we are at about 8.9' of water at the staff gauge by the lake gates, but if we have a really wet spring compounded with the heavy snow, I have seen the lake get up about 13'. When times like that happen, we go WFO with the waste gate, turbine, an additional turbine to pump water to a storage tank, and drop the flashboards. Flows will be in excess of 650-700 CFS, and will flood the yards and such of houses down stream. 

So basically Nuzzie, short story long, an operator only has to be at the plant to check it in the morning, do the daily calculations for power generation, revenue, greasing, etc, and once in the afternoon just to make sure everything is running OK. Extra time has to be spent over there changing river flow, maintenance, and if the plant gets kicked offline during a thunderstorm or whatever, but it's not like a guy has to stand there and tweak the power output all the time. 

If you guys want to know more, just ask. What I don't know I can ask the boss man. Pretty cool side job, huh? :thumbup:


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## 8V71 (Dec 23, 2011)

Going_Commando said:


> If you guys want to know more, just ask. What I don't know I can ask the boss man. Pretty cool side job, huh? :thumbup:


Yeah definitely! What John was saying about power output. So, would you raise the voltage of your unit slightly higher than the grid but the grid is stiff enough that the grid voltage pretty much stays the same. Is that how it works?


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## Going_Commando (Oct 1, 2011)

8V71 said:


> Yeah definitely! What John was saying about power output. So, would you raise the voltage of your unit slightly higher than the grid but the grid is stiff enough that the grid voltage pretty much stays the same. Is that how it works?


You match the power factor, frequency, and voltage to sync the genny to the grid. It is a reaaaaally small window, as if you are leading or lagging the grid, bad things happen if you actually close the breaker. You basically get the frequency close (about 60.4 Hz), and watch the synchroscope until it is at unity power factor with the grid and then slap the push button to close the grid-tie breaker. The protective relays (black boxes with clear covers in grey cabinet posted above) keep you from screwing that up, and won't allow you to close the breaker unless you are at the right voltage, frequency, and whatnot. My 600kW generator is tying into basically every power plant east of the Mississippi, so it's not like you are going to lead/lag anyway, since my plant isn't going to adjust the rest of the grid. 

Once you are synced, you can crank up the gates controlling flow to the turbine, and the grid isn't going to let the voltage/frequency change, until you cut flow enough that the generator turns into a motor being driven by the grid. We have a protective relay to prevent that too.


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## Big John (May 23, 2010)

Going_Commando said:


> ...(plywood held in place by 1" schedule 40 pipes, will describe purpose later)...:thumbup:


 Man, one year we were struggling for manpower because of the winter storms, and my guys got loaned out to the flashboard crew. 1.5" solid steel bar stock. There were about 400 of them that had to be removed and replaced, so you're handling 800 seventy-pound weights. Gained a new respect for the regular flashboard crew.


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## Going_Commando (Oct 1, 2011)

Big John said:


> Man, one year we were struggling for manpower because of the winter storms, and my guys got loaned out to the flashboard crew. 1.5" solid steel bar stock. There were about 400 of them that had to be removed and replaced, so you're handling 800 seventy-pound weights. Gained a new respect for the regular flashboard crew.


That sounds rugged as hell. 

At the last plant I was at, it was always a good time resetting the flash boards since the waste gate didn't open and they were 3/4" plywood 3' tall and 8' long. Lotta fun swinging those around with water flowing around your feet and a 3/8 coated steel cable being the only thing between you and kissing concrete 30' down. The one I'm at now we have a catwalk over the dam and have a hook for grabbing flashboards with, as we nailed hoop anchors to the tops of them. Muuuuch more comfortable.


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## just the cowboy (Sep 4, 2013)

Parker has some good info on hyd systems


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## Nuzzie (Jan 11, 2012)

Well **** maybe I was told wrongly then. I was taught that when load comes on, you get a magnetic field in the stator opposing the rotation of the rotor, slowing the rotor down, and thus your frequency would drop as the speed drops. In response to this the governor opens the wicket gates to allow more water to flow which speeds up the generator to maintain frequency (over here 50hz). And vice versa with load coming off, generator would overspeed, governor closes gates. We get pinged really badly for over or under frequency from the station which wouldn't really make sense if the frequency was fixed outside of our control.


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## Going_Commando (Oct 1, 2011)

Nuzzie said:


> Well **** maybe I was told wrongly then. I was taught that when load comes on, you get a magnetic field in the stator opposing the rotation of the rotor, slowing the rotor down, and thus your frequency would drop as the speed drops. In response to this the governor opens the wicket gates to allow more water to flow which speeds up the generator to maintain frequency (over here 50hz). And vice versa with load coming off, generator would overspeed, governor closes gates. We get pinged really badly for over or under frequency from the station which wouldn't really make sense if the frequency was fixed outside of our control.


Let me see if I can work through this. I am a bit tired, but will do my best. So, when we are working to get the generator synced with the grid, we are bringing it up to the exact RPM necessary to generate 60 Hz (167 RPM in this case). When the generator reaches the correct frequency, the breaker is closed and the generator is synced. We then adjust the guide vanes (Ossberger turbines don't use wicket gates, bit different design) to match the power output we want based on river flow. To keep the generator from loading the grid or the grid loading the generator, the excitation current is adjusted via a voltage regulator circuit to keep the correct voltage being induced into the stator. The guide vane acts as a governor, as only so much water volume is going to be passed through the turbine, since the pressure is essentially fixed. Once the generator is synced, the voltage regulator will automatically adjust the excitation current to match what it needs to be based on the position of the guide vanes.

Forgetting to mention the exciter in my explanation before was my bad. I've been working on 2 hours of sleep all day and am a bit loopy. Speaking of that, I need to go to bed so I can get up in 6 hours. :laughing:


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## Going_Commando (Oct 1, 2011)

Hey Big John, the top basler relay is over voltage protection, and the 2 baslers on the very bottom are under/over voltage relays.


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## Big John (May 23, 2010)

Going_Commando said:


> Hey Big John, the top basler relay is over voltage protection, and the 2 baslers on the very bottom are under/over voltage relays.


 What's the score there? You've got two layers of voltage protection, are the bottom ones unit protection and the top one is utility?


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## CdotJdot (Nov 19, 2011)

it wouldn't hurt to take apart any of those valves that the solenoids actuate and clean them thoroughly if u have time. if the filter was all gummed up more than likely those valves are to


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## Going_Commando (Oct 1, 2011)

Big John said:


> What's the score there? You've got two layers of voltage protection, are the bottom ones unit protection and the top one is utility?


Not sure. Next time I'm over there I'll dig into it some more and fight out. 

So, we have found out part of our problems with the system is that several of the relays in the bottom of the cabinet have bad coils, and they are 1970s vintage. We are planning on just replacing all of them. 

Has anyone used the Weg relays from Automation direct? We need 4 pole contactors with 2 NC and 2 NO contacts to replace the old ones, and it seems hard to argue with $13.

We removed all of the solenoid valves on the hydraulic unit, cleaned them up, and replaced all the prints on the unit, so the leaks are finally gone! Once we hit summer shut down we are really going to tear into the controls and flush the hydraulic unit, and also see about getting the variable valve going again. We are also going to see about ripping out the pond level controller and some other parts in the cabinet that aren't necessary. The pond has never had the volume for the pond level control to actually work. It would just bounce between full power and about 50kW. Stupid design.we will most likely add a Plc to operate the variable speed setup and whatnot to clean up the cabinet and allow for easier control.


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## Jlarson (Jun 28, 2009)

Can't go wrong with weg. I'm excited ADC is starting to sell their stuff.


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## Going_Commando (Oct 1, 2011)

Jlarson said:


> Can't go wrong with weg. I'm excited ADC is starting to sell their stuff.


Awesome, thanks. We'll be ordering probably 15 or so next week, and installing probably the week after next.


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