2200 HP soft start for fan ? crisis 1

[Tmoose]

We have several 2200 HP direct drive fans. They use a hydraulic coupling to let the motor go right to full speed, then bring the fan up to speed over a 3 minute period at ~ constant torque.

We have hit a major lack of spare parts problem with one of the couplings. The pressure is immense to get the fan back on line quickly in order to run ~ 6 months.

The Fan manufacturer says Direct coupling would require ~ 4000 HP motor.

ALL alternatives are being considered.
Short term generator and engine rental, giant soft start devices, 4000 HP used motors.

Dan T

 

[ruggedscot]

This sounds like one to video and post on youtube....

Pretty interesting when you try to work outside of the box and apply some devious thinking to a process....

 

[waross]

Hi ruggedscot;
I don't generally make such sloppy sync's. I am embarrassed by anything past about 5 deg. It's hard to get much closer than 3 deg with small diesels and a manual 1000 amp breaker frame.
However, I was surprised to see just how sloppy a sync could be before it caused damage. These folk would be sync'ing in generators sometimes 10 or 12 or more times a day. Their operating procedure was such that they were sync'ing in generators when the load was dropping as well as when the load was increasing. (Add a 350 kW and then drop a 600 kW) They were doing it for 5 or more years before I found and corrected the issue.
The tip off was that whenever a unit was sync'ed, the syncroscope would jump to the 2 o-clock position when the breaker was closed.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

I think small sets are likely more tolerant than large ones - I'd be concerned about a 30 degrees error on synch for a large turbo machine. The forces are unlikely to approach those of a fault and the machine bracing should be adequate to withstand them but still very undesirable if it is happening on a frequent basis.


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If we learn from our mistakes I'm getting a great education!

 

[waross]

I agree Scotty. The point is, small sets will accept more sync'ing error than any of us thought possible. One poster seemed to be concerned about sync'ing gensets, and I was trying to show, with the help of real world examples, that sync'ing small sets was more forgiving than most of us realized.
BTW, I'm one the plane back to that plant on Monday. They have a fuel efficient 1.2 mW set now and the days of sync'ing in 350 kW and 600 kW sets are behind us.
These trips are more an expense paid visit with old friends than a job. The island is hard to describe but I enjoy it.
The main community is on a coral reef with no roads or motor vehicles. Transportation is by sidewalk, push carts and boats.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

I want your job, well this one anyway. You can keep some of the others you have been on!


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If we learn from our mistakes I'm getting a great education!

 

[itsmoked]

How did they move a 1.2mW er MW set with no roads? Yikes!

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

The plant is only a few hundred feet from the shore. I wasn't there but I understand that they used greased timbers and chain falls. (manual hoists) They would use hydraulic jacks to lower the set off the timbers.
After hurricane Mitch destroyed the entire distribution system, (only three poles left standing and they replaced them rather than trust them) the line contractor and his crew rebuilt the entire system by hand. The poles were set with pike poles, the wire was strung out by hand and the transformers were delivered as close as possible by boat and then dragged overland and hoisted by hand. It was something to see.
You can tell that I am thoroughly confused by Political Correctness in abbreviations. I was quite happy with KVA, KW, MW, MVA etc. (and of course milli-watts).


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

That sounds just great, Bill! I have a few places when I also go on a "payed chat" with friends. But nowhere near your place. I wish I had.

Talking about out of sync. Scate-boarders have their terminology. Like "a 180", "a 360" even "a 540".

I have not got any further than "a 180". That's as bad as bad can be. Read all about it in attached pdf.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[rmw]

Hey, the OP seems to have been pretty well covered and the OT seems to have drifted so I'll add what this ME thought of for a solution. Tmoose, how much real estate do you have available around that PA fan? Do you have enough room to back a pick up truck next to the fan, wrap a rope (hawser) around the shaft several turns and pull it to half speed with the PU truck?

I'm sorry, the wife had me out in the yard this AM with her Suburban and one of my old logging chains pulling up shrubs by the whole root system so I guess my mind was just wandering. But I have seen something like this done in the past, so I thought I'd throw it in. It might take a few trial runs to get it smoothe and to determine what ratio of speed/wraps would get you to 600 RPM, but what the heck.

rmw

PS: a neighbor asked me what kind of plants the were and I told him I was working from my neck down and except that I knew how to operate a logging chain I wouldn't be involved at all.

 

[waross]

Hello Gunnar. I remember your telling this story and thought about it while I was composing some posts. I enjoyed reading it again, and with pictures.
At least at 180 degrees there would be little torque. Worst electrically but I vote for around 90 to 100 degrees as worst mechanically.
I would hire 6 or 8 of my friends from Eng-tips as consultants if I could.
But you probably don't want to see the crime scene photos of the body we found less than 100 yards from my hotel room on the way to the boat to the airport the last time I was here.
I guess I could best be described as a wandering adventurer who pays the bills with some knowledge and experience with electrical stuff.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[edison123]

waross

Can I be one of, them consultants ? I'll behave, I promise...

Seriously though, I like your wandering adventurer attitude.

 

[Skogsgurra]

I feel the same, Bill. Doing fun things in sometimes unexpected places where I never would have gone if it weren't for that drive, that bearing damage or other problem.

BTW, I have always been told that the 180 was as bad as bad could be. But, when I think about it, It is probably not so bad mechanically, force CW or CCW? There is a minimum at 180, as there is at 0. Currents and voltages high, but the breaker survived. Learned again.

Edison. Did you make that drama yourself? Have been looking at it for minutes. Like (some) projects, it starts optimistically and happily, gets difficult, then dangerous. If you stop there, you are wise. Being forced to continue (by your own ego or a boss) may take you where you don't want to be. Starting a 2200 HP fan could be such a project.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[waross]

Hey folks, should we continue this part of discussion in Pat's Pub.
Something like a most memorable service call/ job/ adventure/ injury, location or memorable whatever.
I think that the participants are pub members. If anyone participating is not a Pub member please say so. We can stay here rather than cut you out.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

Can't anyone join the Pub? Or are there any restrictions?

I think that's a good idea Bill. Start a new Pub thread named "I'm in this for the fun - mostly"

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[davidbeach]

It requires an invitation from Pat. I understand that there is a means of requesting membership; but I was invited without asking to join, so I don't know the process for applying for membership in the pub.

 

[macmil]

it's pretty easy ~ hell they let me in !