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World's Largest AC Motor

World's Largest AC Motor

World's Largest AC Motor

Does anyone know where the world's largest electrical Motor resides, what it is used for, and who makes it?  I went to a Large AC Motor GE Seminar and found two motors that was used in a refinery for Motiva that drove Fans.  The following was taken from an IEEE website "The ASU for the Motiva Delaware City repowering project depends upon the proper application and operation of very large synchronous motors, including a four-pole 66000-hp machine and a four-pole 43000-hp machine, the former being the largest 1800-r/min compressor driver ever designed and manufactured."  http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=952516

This article was written in 2001 so there has to be bigger motors since then.

Thanks in advance for any input.  I tried search eng-tips for prior discussions and did not find any.

RE: World's Largest AC Motor

I know that NASA and Boeing aircraft both use 60,000 hp motors on their wind tunnels.

We actually have in our possession the old motors off the Seattle wind tunell.  It was 36,000 hp wound rotor induction motor, 10 pole. It was coupled to a 20,000 hp synchronous motor thru an eddy-current coupling, and had a 450 hp wound rotor pony motor on  the common shaft.

The 450 pony started the sync motor, which accellerated the 3600 thru the clutch. when the unit was up to slip speed, it was closed onto the power system to minimize impact on the utility.

I belive I read an article that both Siemens and ABB both have breached the 80,000 hp rating, but cannot find the artical.

RE: World's Largest AC Motor

We have had this discussion here in the past, but I couldn't find it. At one time ABB was working on a 125,000HP motor and drive for Boeing's supersonic wind tunnel, but that got the axe when Boeing abandoned the SST for the 2nd time recently.

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RE: World's Largest AC Motor

That was 1997 - it was a 101MW variable speed drive and motor. According to ABB's literaturer it was delivered too.


One contender for 'largest' must be the motor-generators installed at the Dinorwig pumped storage hydro station in Wales. 330 MVA generating, 312 MVA motoring, 18kV, 500rpm.


  Sometimes I only open my mouth to swap feet...

RE: World's Largest AC Motor

It would be interesting to know the rated torque as well as the horsepower of some of these big motors. That 36,000 hp, 10 pole motor would produce as much torque as a 90,000 Hp, 4 pole motor and would be comparable in physical size.

RE: World's Largest AC Motor

Miles behind those big Welsh machines:

500rpm @ 4,395,487,000 lb-ft, give-or-take.

Depends a little on what power factor the motor-generator is running at.

  Sometimes I only open my mouth to swap feet...

RE: World's Largest AC Motor

The refinery now belongs to someone other than Motiva. It was sold about 4-5 years ago to Premocor, not sure if they still own it.

The two motors were part of a syn-gas plant that started when the place belonged to Texaco.

I nkow they had some process issues for quite a while and couldn't use the motors.

RE: World's Largest AC Motor

I believe the Dinorwig big electrical machines were made by GEC Machines in Rugby, England - now Converteam Motors. Thanks for the link ScottyUK.

RE: World's Largest AC Motor

Is the 563,400HP (420,127kW) of Pumping Power a single motor or is it multiple motors.  My guess is that its multiple, but what are the motor sizes to equal that amount.  That is very impressive!!!

RE: World's Largest AC Motor

Yes, there are six motors/generators: "six 350-megawatt turbine generators"

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

RE: World's Largest AC Motor

Largest - by size, torque, type output, always a tough one. the propulsion  motors for the QE2 cruise ship are (59,000HP) 44MW at 144rpm. There are two at this rating, each one driving each propellor directly.

Must be "up there", in terms of torque

RE: World's Largest AC Motor

Does any one of you have heard of a big motor that is use to crunch rocks? I don't remember where I saw it (in my dreams...) or at school, or both  sleeping    . Anyway, the rocks were put between the rotor and the stator and the turning did the crushing. The way I see it, it must turn very slowly, if it really exist...ponder      

RE: World's Largest AC Motor

I think that an airgap large enough to crush rocks on a motor large enough to crush rocks with the rotor would need an unrealistic level of magnetizing current.

RE: World's Largest AC Motor

Rock crushers are common in gravel pits and quarries.  Also, for reclaiming old concrete.

The hp's are low, often in the 50 to 200hp range but watch out for the flywheel.  The stored energy in the flywheel does all the heavy work!

RE: World's Largest AC Motor

unclebob; That must have been imagined while you were in an altered state.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: World's Largest AC Motor

may now be worth taking a peek at the offshore oil industry - particularly around the caspian sea where a number of world 'firsts' are happening on a regular basis.

RE: World's Largest AC Motor

I took a tour of the Langley National Transonic Facility (NTF) last year, where they mentioned the fan drive motor was one of the largest in the world. A bit of Googling turned up this press release:


135,000 hp, built by ABB, and continuous duty from 360-600 RPM. There were many reasons I kicked myself for forgetting my camera; this motor was one of them. BIG!

RE: World's Largest AC Motor

They probably would have had mass apoplexy if you'd whipped out a camera anyway.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: World's Largest AC Motor

135,000 hp slow speed... that's a big-a** motor.

My work location has two generators that output 1350Mwe each.  That would be equivalent to approx 1,350,000 horsepower each.  Not slow speed, not motors, but still pretty dang big.

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RE: World's Largest AC Motor

Uncle Bob... have you ever taken apart the 'business end' of a pepper grinder?  It might remind you of that gyratory crusher.  Mind you, the pepper mill just turns and the gyratory crusher presumably oscillates, but it's not so terribly different.


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