And Now MVaR in words of one sylable or less 6

[JJayG]

Here's one for all of you clever electrical chappies out there.
Imagine trying to explain MVaRs to a new starter, ie. in the simplest way possible.
All analogies welcome (except maybe the horse and barge one).
Points may be awarded for creativity but deducted for over technicality.
This has always been one of those questions that,(along with what is entropy?)has been a source of consternation in power stations since Michael Faraday was a lad.
Go On, you know you want to............

JJ

 

[edison123]

Beer and Froth. The bestest.

Muthu

http://www.edison.co.in

 

[waross]

My Fortran formatting is probably way off but;
10 Search this site for the Beer and froth analogy of power factor.
20 do: Take your student to the pub and order a beer for each of you.
30 Use the beer to explain the power factor analogy.
40 Drink the beer.
50 does the student understand power factor?: exit
60 loop to 20

Bill
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"Why not the best?"
Jimmy Carter

 

[jraef]

LOL, loop to 20...

55(?) Unable to stay upright on bar stool?: exit


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

Well the M stands for Million or 10⁶.

What do I get?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[alehman]

and V is for Volt!!!

Alan
----
"It’s always fun to do the impossible." - Walt Disney

 

[edison123]

R = Radical

Muthu

http://www.edison.co.in

 

[burnt2x]

I got this while surfing the web:
"MVARs are like managers, they take a lot of room, increase losses, doesn't do useful work, but are still required to obtain the "REAL" work at the end of the line."
Please wait 'til someone else tells you a far better answer!

 

[Skogsgurra]

Burned and Smoked

You two win the prize!

BTW. It is var nowadays. Not VAr or anything like that.

Gunnar Englund

http://www.gke.org

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

 

[itsmoked]

vars are like railroad tracks. They HAVE to be there to move the freight but aren't used up or directly paid for by the people receiving the freight.

Some companies will assess specifically for using the rails(vars) others won't.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

JJayG;
We have many times in the past, tried to explain this concept. To para-phrase Lili von Stupt in Blazing Saddles:
"We're Tired!"
For a more serious treatment of the VARs concept, search this site. (I'm sorry Gunnar, I tried vars but I couldn't do it.)
Is this a European Union harmonization thing?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[wolf39]

JJayG:
This thread got the responses it deserved. Sorry.

burnt2x:
Excellent description, I must remember this.

Gunnar:
V and A I've learned and I'm used to write in capital letters as they are derived from Mssrs. Volta and Ampere. The r stands for reactive and is always written as a small letter in Europe. In the U.S. they have a different opinion, however. Would be nice to know whether there is a new standard regulating this.

Regards

Wolf

http://WWW.HYDROPOWER-CONSULT.COM

 

[Skogsgurra]

Wolf and Bill,

Yes, as always, the BIPM has set the rule. Reactive VA is a unit (has been so for something like 20 years) and shall be written "var". If we are at all going to have a unified and standardized technical language, we need to adhere to rules laid down by the top standard institute.

I know, it hurts, but instead of using VAr or VAR or VaR or, perhaps vAr or... I think it is meeaningful to use what the BIPM says. Privatized writing like the ones used above only confuse. And so do "simplified" explanations. But I liked the manager explanation.

We had a similar discussion a few weeks ago where the unit for temperature change was discussed. Same thing there. K is the unit to use while C or F are units for temperature. Most people seem to think that C and K are identical. They are not. BIPM agan.

Gunnar Englund

http://www.gke.org

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

 

[rbulsara]

While Gunnar is technically right, in this case the standard (IEC and SI) is not consistent or at least it feels that way.

The issue is that the common expressions, such as kVAR or KVAR have been in use longer than the so called adoption of 'standards'. And hence the use of var in common writing will not be any more accepted than it has been in the last 20 yrs. Arbitrary and retrospective standards will always find the acceptance harder. Just like K vs. C or F.

I also start out writing var (since I learned of this not too long ago) in many cases and then usually decide to change it to kVAR to match with kVA in the reports.

It is no different than use of KVA for kVA. or KW for kW. All have been very common in writing and equipment data sheets/name plates with no real confusion or opposition.



Rafiq Bulsara

http://www.srengineersct.com

 

[ScottyUK]

Difficult to argue with the IEV even if the IEV flies in the face of common sense when the generic volt-ampere is denoted VA. Idiots.

The BIPM is run by the French isn't it? That explains everything...

http://www.electropedia.org/iev/iev...da8ebfc0351ec848c1257275005d79dc?OpenDocument

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

 

[Skogsgurra]

It is not about being an idiot or not. The VA is V times A just like Nm is N times m. The var is different. It is not V times A times R. Hence the unit var.

Gunnar Englund

http://www.gke.org

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

 

[PHovnanian]

For those who are graphically inclined: VARs, power factor, and phase angle can be illustrated by drawing two sine waves (preferably on a piece of graph paper) and their product. By changing the phase relationship, the unidirectional and reversing flows of real and reactive power components can be seen.

If the subject doesn't 'get' this, I usually fall back to the beer/suds explanation.

 

[ScottyUK]

Well, the V and A are both capitalised because they are the initials of the men they were named after. The 'V' and 'A' in 'var' represent the same Volt and Ampere that they do in VA, so they should be capitalised. Even the IEV acknowledge that it is a "special name of the voltampere in the case of non-active and reactive power". The 'r' would be a subscript if we were following the rules of logic and grammar. But we aren't.


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

 

[rbulsara]

I am at least thankful that engineering standards have not reached the low of botanical or biological sciences where 'Turdus migratorius' can be insisted up on as the correct scientific name for a bird where just a American robin would do.

Although, if the engineering standards keep up with nerdy ways, they will end up there.

Rafiq Bulsara

http://www.srengineersct.com

 

[cranky108]

What does all this mean? Have we confused anyone yet?

We are off subject.