Kva & kw

Replies

• 

  d_vipul

  Volts x Ampere = VA (VoltAmpere)
  Volts x Ampere x power factor = kW (Watts)
  
  Divide 150W by 0.8 power factor (which is the max. power factor of home standard) to convert it in VA........
  Means you are supposed to buy a inverter of 150 / 0.8 = 187.5..........so you have to an inverter of rating greater than this like 200 VA or 250 VA whichever you want..........
  
  Hope this answer satisfies you........
  If have any doubts then feel free to ask here............
  
  Regards,
  Vipul
• 

  ABCD ABCD

  What about 'time' factor of the inverter?
  What is the significance of VA over Watts(Please Explain)?
• 

  ABCD ABCD

  any answers?
• 

  narayana murthy

  i think time factor deals in energy but not in power and by considering VA it is real power so it is very necessary for inverter
  and if you are asking about time regarding to inverter properties i think it gives the time which it will supply to load when power is went off
  @others: i don't know any practical apps because i am still in study so i can't say exactly if am wrong anywhere please correct me i too will know and learn it
• 

  praba230890

  We use kva for the representation of Electrical Apparatus ratings(like transformer, relay, etc which doesn't consume power but carry it), while we are using kw for Electrical Appliances which consumes power. That's why we are adding time factor in kw i,e for how long you consumed the power.
  Also kva ratings were the maximum withstanding power of a device or an appliance, if you supply an apparatus more kva than it is on name plate it will heat the device and damage it.
  

  mreccentric

  I have forgotten the main differences b/w the VA and Watts.
  Can anyone explain me the differences between them properly.
  Moreover, what VA should i prefer when buying an inverter.
  I want to light 150W of Lights for 4hours, what sort of inverter should i buy? How to convert from VA to Watts.

• 

  ABCD ABCD

  Would the output of inverter affect the appliances?
  I mean pure sine wave output and modified swqaure wave output.
• 

  cranky

  mreccentric

  Would the output of inverter affect the appliances?
  I mean pure sine wave output and modified sqaure wave output.

  Yes it would.We go for a modified square wave only cause the cost is less.But as far as I could gather,the efficiency of pure sine wave is much better.Also check the attachment for the equipments that would be affected
• 

  PraveenKumar Purushothaman

  The battery discharge time is calculated by Peukert's Law.
  Ref: www.smartgauge.co.uk 😀
• 

  ABCD ABCD

  cranky

  Yes it would.We go for a modified square wave only cause the cost is less.But as far as I could gather,the efficiency of pure sine wave is much better.Also check the attachment for the equipments that would be affected

  How is cost less? Thanks, information was useful.
  

  praveenscience

  The battery discharge time is calculated by Peukert's Law.
  Ref: www.smartgauge.co.uk 😀

  Peukert's Law, heard it for the first time. But was aware of the concept.
• 

  PraveenKumar Purushothaman

  I was searching like hell for Peukert's law... And is it only applicable for Lead Acid battery or all others too???
• 

  praba230890

  There are two types of inverter outputs we could use. One with pure sine wave and other is distorted one(may be square wave too). The purer the sine wave the higher the power quality. As the distortion increases the risk of damaging the appliances too increases but u can see the cost of inverter decreases. It's your choice to choose quality power or cheap power. The main thing about impure sine wave is that they have harmonics along with distortions. Which are considered to be the enemies of power quality. These harmonics may reduce the life time of our appliances(currently we are having appliances costs 10,000-100,000 Rs).
  I think this may help you a bit about generation of pure sine wave
  

  mreccentric

  Would the output of inverter affect the appliances?
  I mean pure sine wave output and modified swqaure wave output.