1350 KW 3600 rpm Synchronous Generator

[WildBlueYonder]

I have been looking for a 60 hz, 1350 kW rated synchronous generator that runs at 3600 rpm.

I can't seem to find one!

It is essential for my project that the generator be synchronous and generate at 60 hz. It is also essential that it run at 3600 rpm. There is flexibility in power rating (down to say 600 kW), and supply voltage is also flexible.

Can anyone point me to an available product/source?

Can anyone explain to me why it seems so hard to find a synchronous machine in this size range at 3600 rpm? There are many options available at 1800 rpm. Is there physics underlying the synchronous machines that render operation at 3600 rpm infeasible in this size range?

Thanks in advance!

 

[rmw]

In that size range it is more economical to build 4 pole generators than 2 pole models. It could be built but the $$$ would be more than a corresponding 4 pole model.

Might I ask why it is essential that it run at 3600 rpm?

rmw

 

[WildBlueYonder]

I have a special purpose turbine already designed and I 1) don't want to use a grearbox and 2) don't want to have to do a new turbine design.

BTW, the issue with the 3600 rpm synchronous generator in this size has not been price, it has been finding one altogether! I'd glady pay some premium to save having to effect a new turbine design or go to a gearbox!

 

[motorspert]

Wildblue,
Are you looking for power factor control, will you be connecting to a grid? You could consider an induction generator, I have just installed one at 20MW so 1350 is no problem, but if you want power factor control, you will need something more elaborate. I have something in mind but need to check it can eb done before i make a fool out of myself.

r

 

[WildBlueYonder]

Yes, I am aware that in this size range I can readily get an induction generator, or a synchronous generator at 1800 rpm. The challenge is finding a synchronouse gnerator at 3600 rpm, and I came here after an exhaustive search of the web (and much else), so I am really starting to believe that synchronou generator at 3600 rpm in this size range is non-existant!

I hope someone here proves me wrong!

Please, prove me wrong!

Thx in advance!

 

[waross]

It will probably have to be custom designed and constructed.
Large 3600 RPM generators are direct connected to very large steam turbines. The generators are custom designed and built.
You may want to ask the drive experts for an opinion on using a 60 Hz. machine at 120 Hz. and using a VFD to convert to 60 Hz. The electrical equivalent of a gear box. An added bonus would be the ability to run the turbine at the most efficient speed, not exactly 3600 RPM. The drive experts can suggest the reasonable speed range.
A 750 KW, 1800 RPM machine is capable of outputting twice the voltage at 3600 so the limit would be about 1500 KW at 3600 Rpm/120 Hz.
respectfully

 

[byrdj]

If you are looking used, I googled and found a few

here is a 1360KW with a gearbox for a 3600rpm turbine

http://www.utilitywarehouse.com/info1/westinghouse136stg.htm

And here is a 1500KW direct

http://www.utilitywarehouse.com/info1/worthingtonstg.htm

 

[rmw]

By price I meant that no one builds 3600 rpm generators in that range because the 4 pole mfgr's can make the same Kw model so much cheaper that why bother.

What is your aversion to using a gearbox? Geared turbine/generators is commonly done.

rmw

 

[motorspert]

Waross,
If a vsd is being considered, an induction machine would be ideal, ie cheap,and the vsd could give a good waveform out at 60Hz.

I think the bsecond hand unit proposed by byrdj may be a good option, but doesnt look like it is brushless. I believe the servbice group of EM could refurbish and add a brushless exciter.

The difference between a 4 pole and a 2 pole at this rating is substantial. A new 4 pole would be around $50k and a 2 pole with a solid rotor etc i would imagine could be 10x that. It's not so much the material and development costs, its the more to do with capacity - while they are machineing and winding the 1350kW rotor they could be knocking out a 200MW machine! And these boys are busy, some are quoting 4 years lead times!

 

[Hoxton]

Smallest 2 pole (3600 or 3000 rpm) generator i saw built was a 10MVA (8MW) set, driven by an Orenda gas turbine. Light weight was the main criteria, as it was to be mounted on a railcar.

Main application at this speed is turbine driven generators, and both steam and gas turbines at this size often run at very high speed, so a gearbox speed reducer is required. In that case, it is more economic to gear down to lower speed (1800 / 1500 rpm) and have a cheaper 4 pole generator.

That the main reason that you do not see two pole generators much below 20MW, as far as I remember.

 

[ggratecc]

In the U.S. Navy, 2-pole , 3600 rpm, 60 hz, 2000kw, 480v synchronous generators are very common...
of course price is NO object.

Maybe you can find a military salvage.
Also, check

http://www.powermag.com

for vendors...it is
their power plant buyers's guide.
try this:

http://www.tradefairgroup.net/powerconnect/search_results.asp?vartype=search&varkey=3600+generator