Synchronous vs Induction Motors 1

[dennisk]

I am looking for info on selection of induction versus synchronous motors in a medium voltage, over 1000 HP, adjustable speed drive pumping application.

Any help would be appreciated!

 

[jwerthman]

Check the Robicon web site. They probably have some background info on this subject.

http://www.robicon.com

 

[jraef]

As a generalization, synchronous motors are typically selected because a) they are needed for additional purposes such as acting as a synchronous condensor, or b) the application needs a low rpm motor and you don't want to sacfifice efficiency and/or add cost by gearing down a 4 pole asynchronous induction motor.

The second issue is made moot by using a VFD. You will be able to run at reduced speed while saving power (assuming it is a centrifugal pump) using a standard "off-the-shelf" squirrel cage induction motor.

If on the other hand, your entire facility has a poor power factor, the synchronous motor can be run at a leading power factor and correct for the other loads in the facility. In this case your motor will be acting as a synchronous condensor. Candidates for this use are mtors that run continuously for long periods while the other poor power factor loads are also running. If this pump will cycle on and off, it is probably not a good synch. condensor candidate. Don't worry about the PF of this particular motor, if you use a VFD it will maintain a .95 PF to the line without needing to use a synchronous motor.

Did this help? Subvert the dominant paradigm... Think first, then act!

 

[jbartos]

Suggestion: Visit

http://www.ge.com

and search for AC Motor Drives
for more info

 

[jbartos]

Suggestion:
Usually, LCI are used to control speed synchronous motors, e.g.

http://www.geindustrial.com/products/brochures/GET-8021B.pdf

http://www.hpcnet.com/course_info/e/e505.html

http://www.minasco.com.au/MisimaTreatmentPlant.html

http://eic.changwon.ac.kr/bk21/asp/mecha/data/acdrivey2k.pdf

http://www.teco-wmc.com/Controls/fm2000/

(Universal AC Drive)
etc. for more info.
1000HP motor with associated drive is relatively small for synchronous motor and LCI drive. The squirrel cage induction motor and VSI or CSI drive topology can be considered. There are a few manufacturers who offer this technology.

 

[CB2]

Contact the following for medium voltage, 2300-4160, VFDs and motors:
AB
ABB
GE
Robicon
Toshiba
All on

http://www.drivesmag.com