Synchornous Motor Variable Speed

[buzzp]

I am new to synchronous motors and wanted to know if there is any equipment out there to vary the speed (and excitation preferably in one package)? These are large MV motors (4160 I believe, more info is supposed to be coming in).

 

[buzzp]

Alright I am guilty of not doing a little research first. So they do make drives for these (V/Hz). Should we be looking at a certain type (vector control?) for a pumping application?

 

[Skogsgurra]

For these large machines so called cyclo-inverters with vector control was used during the last twenty or thirty years.

But the kV IGBT PWM frequency inverters are being used more and more. You see them in large pumps, steel mills, thrusters and so on.

Visit ABB, Siemens, Stadt and many other manufacturers.

 

[Skogsgurra]

Hi buzzp,

Slipped? I guess that you answered another question here?

 

[buzzp]

Hehe, I did. I have had problems reading lately it seems. I generally am very good about researching something I am working on before I ask questions. Whether its good or bad, I find myself turning to this site as a first stop in my search. This is one that should not have been posted if I had done just a touch of investigation.
Of course, I never rely on any info on this site but it does give me a place to start. Thanks for the posts peoples.

 

[Dopler]

GE makes LCI, load commutated inverter, to be connected to a synchronous motor and have variable speed.

Try

http://www.geindustrial.com/cwc/products?pnlid=7&famid=13&catid=112&id=innovlci&lang=en_US

 

[jraef]

Robicon is probably the leader in MV pumping drives and they do have lots of experience in synchronous. They have Vector control but it is usually not that big of a deal on pumps.

"Venditori de oleum-vipera non vigere excordis populi"

 

[ScottyUK]

CEGELEC Projects have experience in large synchronous machine control. If I recall correctly, they marketed their range under the name SyncDrive or SynchDrive. The drives I worked on were bespoke designs.



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

 

[rconnett]

Be sure the drive manufacturer is aware of the motor type.

For years it was standard design to use LCI type drives on the largest VFD applications, and synchronous motors are perfect for this application. However, LCI is an old technology (in fact the original technology for large drives). It requires a lot closer match of the drive to the motor than a PWM type. Newer PWM type drives are more robust and forgiving - especially if the data is not very good on an existing motor, since the drive requires the back EMF of the motor to turn off the drive gating devices.

Also - vector control is unnecessary with a synchronous motor - vector control is to manage the amount of motor slip under varying loads, and synchronous motors have, by definition, zero slip.

The drive people are familiar with the application & excitation requirements - talk to them.

Suggested vendors:
Robicon (my favorite - my opinion only)
Toshiba (close second)
GE
ABB
Siemens
Allen Bradley (maybe?)

I am currently working on a 30,000 hp synchronous motor application on a VFD so I have a little recent experience with this....

Good luck!

 

[buzzp]

Thank you for the posts.
We are working on the feasibility of using a drive for this particular application. Once we decide it is the way to go we will be looking at vendors. Thanks again to all.