New Orleans Pumps 2

[unclesyd]

I caught the tail end of an interview where it was mentioned that the electric motors that run the drainage pumps are 50 cycle and they have to have a special power plant up and running. I have a lot of information on the drainage system but no mention of the type motors except that the last pump installed had a synchronous motor.
I was just wandering if this true.

This is curious as my home near coal and ore mines and steel mills had a lot of 50 cycle equipment. In fact the company towns around the mines and mills had 50 cycle power, free, so everything electrical had to came from the company store.

 

[jraef]

Absolutely. I worked on a barge just like that near Seattle when they had a prolonged drought and the main reservoir level dropped below the intake for the water system (they never expected it to NOT rain in Seattle). That is exactly what they did, but they did it with 20 separate 100HP pumps hooked up to big hoses because thay had to do it quick.

Still, in this application they would need to have the generators floating as well. Still not impossible, but if it came up in a meeting I'm sure it was shot down due to cost. Hind sight is always 20/20.

Another thought that crossed my mind on this:
If you know that the water is not going to get much higher than the tops of the levees, couldn't you build a coffer dam-like structure around the pumps and generators that is a little higher than that? I'm watching them build the new Bay Bridge in the SF Bay, and for the pilings they build these gigantic coffer dams in the water, then pump the water out of them, making a "hole" in the bay to work in. I'm sure the size is limited by the available structural strength of the materials, but I could envision some very big pump systems fitting in those. Throw on a little paint and grow sme Kudzu on the outside, and they could blend in with the surroundings.

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[itsmoked]

I thought of that jraef but then thought about servicing headaches that would come with the design. You would have to climb ladders up and down the outside and inside. Carry all the tools.. ugh. Or put expensive (small) doors thru the coffer. How do you get the big parts out? Over the top with a crane... The operator of which can't see what's going on. Then if you have a power/fuel failure, both likely in this horror scenario, and a leak is present... Whereas everything mounted on skids welded on top of any number of standard floats even as lame as barrels would intrinsically work and be walk/float up maintainable.

I did also think maybe innocuous 3 story slip poured buildings with everything of import mounted on the third floor would work too. Maybe more conventional(cheaper) and fixed in space, easier to work on and maintain during this kind of event(understatement).

 

[MikeHalloran]

The buildings in which the current pumps are housed are not bad looking buildings, thanks to some pretty fancy brickwork.

But recent threads about the tsunami lead me to believe it may be years before they get the powerplant and the electric motors dried out well enough to survive startup.

Those big pumps, thanks to the low head, need relatively little HP to drive them. You can get enough from a pretty small, pretty portable Diesel. The design speed of the turbines is such that you could strap a big pulley onto the electric motor shaft, rig a small engine with a small pulley next to the motor, and run the pump without bothering to dry the motor, the powerplant or the distribution system.

The engines can be rented; they use them to run emergency pumps for salvaging ships. With air-cooled Deutz engines, exposed flywheels, and compressed air start, you just keep feeding them fuel, and they just keep running, no electricity anywhere near them.




Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

Nice idea. Does anyone know what style of pumps they are? Are they a below grade vertical shaft or an above grade horizontal?

 

[electricpete]

You would of course need to take a close look at the bearings before you try to convert to belt drive.

These are large machines.

Sleeve bearings are not suitable for belt loading.

Anti-friction bearings on large machines designed for non-belt operation may not have enough margin to handle the radial load associated with a belt.

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[electricpete]

The question above on why would anyone use 25 hz?

My guess is that it is cheaper to build a low-speed motor at 25hz.

It would have one-half the number of poles of the same motor at 50hz.



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[rmw]

In one of the links given in this thread or possibly the other ones that are current on this subject, the reason for 25 Hz is given in some detail. I just can't remember which one it is at this time.

rmw

 

[BJC]

25 Hz was one of the early frequencys used in several places. There was a hydro plant at Niagra Falls and one on the Mississippi ( first dam upstream of St Lousi I believe ) that were 25 cycles. 25 Cycle lost out to 60 and those plants were changed to 60. The New Orleans pumping plants being isolated didn't have to change.
The dam on the Mississippi had one or two generators that are 25 cycles and used by industrial uses that have 25 cycle equipment.

 

[MikeHalloran]

Absent numbers, I'm guessing maybe the motor bearings could stand the radial load associated with a drive belt, provided the motor is unpowered of course.

If that's too risky, one could attach a u-jointed short driveshaft to the nondriving end of the motor, and set up a pulley with its own support and bearings there, so the motor would only have to transmit torque to the pump.



Mike Halloran
Pembroke Pines, FL, USA

 

[bigfoot58]

I have seen many misconseptions on the news and other sources where statements have been made that New Orleans was built below sea level. New Orleans has sunk due to compression of the river silt it was built on.

 

[jraef]

25Hz came as a result of retrofitting some existing water turbines that turned at 250 rpm. Tesla just kept it simple and added poles accordingly. From the website I posted earlier on the Rankine power station

The original turbines, with their massive shafts, were designed to operate at 250 rpm so 12 pole generators were envisioned which produced 25Hz to take advantage of the already-installed turbines.

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[itsmoked]

On the subject of New Orleans, NOAA has some extremely revealing sat photos that you might be interested in. They are extremely high resolution shots that are large AND detailed. The more of them I look at the more clear the disaster becomes. There are places that pumps will not reach and must drain/evaporate eventually. Shipping containers where blown around like confetti! I suggest you save these pics to your computer so you can zoom them up to 100% and wander around in them as the detail is incredible.

Here are links to a few of them:

http://mfproducts.nos.noaa.gov/storms/katrina/24431127.jpg

http://mfproducts.nos.noaa.gov/storms/katrina/24431080.jpg

http://mfproducts.nos.noaa.gov/storms/katrina/24440727.jpg

http://mfproducts.nos.noaa.gov/storms/katrina/24430900.jpg

What's with all these cars?

http://mfproducts.nos.noaa.gov/storms/katrina/24425441.jpg

Here is the master link:

http://alt.ngs.noaa.gov/katrina/KATRINA0000.HTM

Google's maps are very nice too with live scrolling and click for Katrina.

 

[rmw]

I spent quite a little bit of time looking at those NOAA photos yesterday and it is slow loading (wireless B). I did locate Entergy's Little Gypsy, Nine Mile and Waterford power plants, and they all look OK.

My question is; does anyone know the approximate location of any of the S&WB pumping stations so that I can go directly to an appropriate photo instead of having to wade through all the photos? I can use a street map for navigating the NOAA picture frames.

rmw

 

[SlideRuleEra]

Pump Station Locations
#1 Intersection Broad & Melpomene Sts
#3 Intersection London & Marigny Aves
#4 Prentiss & London Aves
#6 Upper Protection Canal, back of Metairie Cemetery
#7 Intersection Taylor Ave & Orleans St

This information (from page 31), and more, is available in the 112 page book "National Register Evaluation of New Orleans Drainage System, Orleans Parish, Louisiana" (free .pdf download) at

http://www.mvn.usace.army.mil/pao/history/NO_Drainage/NewOrleansDrainage.htm

http://www.SlideRuleEra.net

 

[unclesyd]

Here is another route through

http://wether.gov

to some of the pictures. You can get very close by drilling down.

http://www.noaanews.noaa.gov/stories2005/s2495.htm

 

[unclesyd]

The TV has been showing some of the pumphouses this morning and it look as if one was testing it's pumps. Three of them look in very good shape.

 

[itsmoked]

I did extensive photo research on the pumps listed in SlideRuleEra 's post. All the pump staions look unflooded(yes!). A few look like they may have a little water on the floor (inches?) But none look close to being drowned. I couldn't find (Prentiss).

Last night on the TLC? as I was looking this stuff up, the show about N.O. came to the pump stations. They interviewed an operator and showed a station. They explained that the whole system was designed to remove 2"(rain) in the first hour, then I think 2" in the next 5 hours? Anymore rain than that and THERE WILL BE Flooding. Seems a little inadequate to me.

 

[DickDV]

Speaking of 25Hz, I believe some of the buildings in the US Steel Gary Works are still 25Hz. At least they were about 7 years ago when I was in the plant.

 

[unclesyd]

Here is one type of auxillary pump (Hydroflow) the COE is getting to assist in dewatering of NO.
Check out the pdf as they have capacities up to 120,000 GPM.

http://www.mwicorp.com/pump.html

 

[itsmoked]

Strange looking that!