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Difference Between VSD and VFD?

07/09/2012 6:55 AM

Can you tell me what is the difference between VFD and VSD?

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Re: diff bet VSD and VFD

07/09/2012 7:02 AM
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Re: diff bet VSD and VFD

07/09/2012 8:23 AM

From the above link:

"a VSD (Variable Speed Drive) or VFD (Variable Frequency Drive) (these are the same thing, just different names for the same unit), a motor will soft start, and you can vary the speed of the motor, by varying the output frequency from the VSD or VFD. "

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Re: diff bet VSD and VFD

07/09/2012 8:31 AM

VSD is for DC applications.

VFD is for AC.

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#4

Re: Difference Between VSD and VFD?

07/09/2012 9:56 AM

"A rose is a rose is a rose; by any other name it smells as sweet"

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Re: Difference Between VSD and VFD?

07/09/2012 10:32 AM

It's actually more like "All squares are rectangles, but not all rectangles are squares." All VFDs are VSDs, but not all VSDs are VFDs

VSD =Variable Speed Drive and could mean ANYTHING that varies the speed of a motor driven load, AC VFD, an LSI drive, a Cycloconverter drive, a DC drive, a mechanical variable pulley drive (Reeves Drive or Varidrive), an Eddy Current Clutch drive or even a hydraulic variable speed drive.

VFD = Varible Frequency Drive, a small subset of VSDs that change the speed of AC induction motors by artificially altering the frequency and voltage together. Then under VFDs there are yet further divisions, but for the most part, most are PWM Inverter drives. Then under that there are yet further divisions.

Unless of course you were using VFD to mean Vacuum Fluorescent Display, or Volunteer Fire Department.

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#6

Re: Difference Between VSD and VFD?

02/22/2014 2:48 AM

Dear Mr.luv123,

This topic discussed few times.

Pl. open the link below and you will find good response

http://cr4.globalspec.com/search/sitesearch?do=show&order=asc&sort=textmatchrank&srch=VSD%20vs%20vfd

I have also replied in the link http://cr4.globalspec.com/comment/857422, which is as follows

VARIABLE SPEED DRIVE and VARIABLE FREQUENCY DRIVE - OPERATIONALLY as the NAME or TOPIC INDICATES- the speed is varied.

THE VSD NEED NOT RELATE to Electrically Controlled speed variation and it is on account of MECHANICAL ASPECT in POWER TRANSMISSION. Example: usage of REEV's Pulley, where the Speed is VARIED by varying the Pitch Circle for the Belt Contact.

VFD necessarily refers to electrical side, by conversion of Power AC to DC and again convert to AC with frequency different from the original Power Supply.

Thanks,

DHAYANANDHAN.S

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