VSD VFD???? again 1

[justlearning2]

Hi
Could someone please tell me the difference between VSD's and VFD's.
Is it that VSD are for DC and VFD are for AC.
How do they operate?
All help is welcome.
Thanks in advance,
Brendan
Hopefully my stay in this forum will longer this time.

 

[jbartos]

Comment: Reference:
1. IEEE Std 100-2000 "The Authoritative Dictionary of IEEE Standards Terms," Seventh Edition, IEEE Press, 2000,
page 238 presents a definition of Converter (1)(General) as a machine or device for changing alternating-current power to direct-current power or vice versa.
(There does not appear to be a typo.)

 

[jOmega]

JB
Also look up
Inverter

 

[peebee]

jbartos, good luck, but I don't think j0mega will ever change his mind, even in the face of overwhelming evidence.

 

[jOmega]

PeeBee

I'm actually underwhelmed

10,000 wrongs do not make a right.

So, believe what you will... That is your right.

But do consider that if we brutalize the language and the definitions that have been standardized.... then one day soon, we will be talking about a car when we actually mean a cat... Both are three letter words that begin with C .. So, if you are talking about a Car, and I think that is a cat... we never will understand each other.

Great communication..

BTW: The IEEE Std 100-xxxx defines
[blue]"inverter(1)(electric power) as a machine. device, or system tha tchanges direct-current power to alternating-current power."[/blue]

So what would you like to call it, a frammistan perhaps ? It's as good a word as any other, isn't it ? And of course, everyone will instantly know exactly to what you are referring when you use the word "frammistan"
p.s. and JBartos is correct in his reporting of IEEE Std 100-2000 and the cited definition of converter (1)general).

So what does it all mean... even the guardian and progenitor of the word.... cannot seem to get it right....

Converter.....Inverter..... Thing-a-ma-bob...call it what you will... Perhaps someone will understand you after all..
..... Hmmmmm.
/30

 

[VWedelich]

In the early start of these drives they used to call them all VSD's AC or DC, then later to make the drives clearer they called them VFD's and VSD's.

VFD is a variable frequency drive (on an AC circuit you must vary the frequency to vary the speed of the motor)

VSD is a variable speed drive.

The VFD is used on AC motors, but never used on a DC motor and the VSD is used on DC motors only. To vary a DC motors speed you must vary the DC voltage.

Look at Toshiba's or AB's websites.

 

[jbartos]

Suggestion: It appears that the jOmega used the older definition (2) in the IEEE Std. 100-2000 Dictionary. Definition (3) below (2) is as follows: Inverter is equipment that converts direct current (dc) to alternating current (ac). Any static power converter (SPC) with control, protection, and filtering functions used to interface an electric energy source with an electric utility system. Notes: 1. The term "inverter" is popularly used for the converter that serves as the interface device between the PV system DC output and the utility system. However, the definition of SPC more accurately describes this interface device. Because of popular usage, the term "inverter" is used throughout this recommended practice. It should be born in mind that this inverter includes the controls, protection, and filtering functions as described in the definition for SPC.
Etc.