300kW Rotary UPS 3

[EEIre]

Hi,

Does anyone have any useful links to technical and reference data on Rotary UPS?

Any experiences/insights anyone may have would be most welcome

Regards

Sean

 

[Skogsgurra]

AVK MG sets and UPSes have been around for "centuries" a good start is to have a look at their site:

http://www.newage-avkseg.com/english/00_home.html

 

[ScottyUK]

Caterpillar make a nice range which has been around for a few years.

http://www.cat.com/cda/layout?m=37516&x=7

Eurodiesel - now part of GE, and good luck on finding it in their website! - have some excellent products which are very popular with the major financial institutions in The City. That speaks a lot about the quality of the product. The electrical machine is an interesting design in itself.

Anton Piller have been around since long before my father was born. Similar product to the Eurodiesel range, with similar spec, reliability, and reputation.

http://www.piller.com/asp/start.asp

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

 

[rbulsara]

Be aware of differeces between true rotary UPS that employs motor-generator in nomal mode and those just using rotary batteries. One using rotary batteries are static units (rectifier/inverter) and rotay battery comes in play only during a power outage for a few seconds.

Conventinal rotray UPS would use regualr battery back up, but supplies normal loads through a M-G set.

 

[EEIre]

Guys,

Thanks for the useful info

Regards

Sean

 

[AusLee]

Hi,

0. what if the engine does not start?

1. what if a prolonged dip occurs? the stored energy is barely enough for a few seconds and depends on the active load.

2. What am i paying for if i don't really need ALL my load to be on UPS?

3. What about the extra synchro cost in the ATS for the Soft-takeover option when network is back up again?

4. What if my site is distributed: i have 2 UPS in 2 buildings rated to 1/3 of the load, what do i do in this case? keep one Gen in one building normal and switch the Gen in the second building to UPS 2/3 full power and have 4 vertical distributions instead of 2, and 2 horizontal cables between the buildings?

The most secure network we have made so far is:
1. Normal supply from network, with
2. UPS for the critical load, 15 mins backup, with
3. Two generators, each rated to the full load, with
4. Alternative supply from another MV ring.


Bottom line: i think comparing the cost of replacing the batteries with that of replacing the bearings is not appropriate and the rotary UPS only finds application where it's feeding one load fully rated load.

 

[ScottyUK]

AusLee,

I guess you aren't a fan of rotary UPS systems. Personally, I think both have a place, the decision being the usual tradeoff of space, maintenance costs, capital cost, ultimate reliability, etc. In response to your questions, the following comments relate to the systems employing a diesel engine close-coupled to an electrical machine ona common bedplate. I don't have much experience of the Caterpillar type using a rotating enregy store and I won't comment further on them.

At least one of the manufacturers I listed tries an electric start of the engine. If that doesn't work, it dumps the clutch and starts the engine using the rotating mass of the electrical machine. Brutal but very effective.
Second fallback is install multiple units. You are having a very bad day if they all refuse to start.

You totally overlook the fact that static UPS units have lousy fault-clearing ability when the utility or backup generator is not available. Rotaries are excellent at clearing faults. How would you explain to your customer that you dropped their data centre or trading floor because a breaker or fuse didn't clear? I have been bitten by the breaker-clearing problem before, although thankfully it wasn't my UPS - we were brought in as independent consultants to establish what happened! Personally I would prefer a multiple-redundant rotary over any static system I've yet seen if ultimate reliability was the design intent.




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

 

[rbulsara]

Auslee:

to add to what ScottyUk said:

You can have (and usually provided) conventional battery back up for a rotary UPS such as Pillers, same as you have for a static system. The rotary battery UPS (made by Cat or Active Power)are the ones to watchout for as they have all the disadvatages of a static unit and the all the ones for a rotary batteries that you mentioned.

Conventional units, mechanical bearing issue is not a issue at all, as they are very predictable while failures on electronic components are not predictable.

 

[ScottyUK]

Something I totally forgot to include in my list of benefits of rotary types over (older) static types is their ability to deal with very distorted load currents without any degradation of the voltage quality. Modern static types do a good job of maintaining sinusoidal output too, so the performance gap is not so wide as once it was.



----------------------------------

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