Running an A.C device on D.C power

Replies

• 

  Jeffrey Arulraj

  Post the current and VOltage reading Then the required circuit is easy to predict But remember this the required battery voltage must be minimum Sqrt(2) times more than the operating voltage of the device
  
  If 220 V then the battery supply must be of Sqrt(2) * 220 got it
• 

  zaveri

  Sqrt(2) = 1.414
  
  hence 1.414 * 220 = 311.08 volts.
  
  is that so ?
  
  by the way, what about the current?
• 

  Jeffrey Arulraj

  True cos the DC voltage got from a rectifier is 1/sqrt(2) times the AC supply voltage. So for the converse to take place you need the product of Vdc and sqrt(2) to get the rated voltage
  
  Let us hear if this is proper #-Link-Snipped-# do comment here buddy
• 

  lal

  Well, it would be better to use an Inverter I guess (Assuming the frequency is not in MHz range). An oscillator is actually not used to provide any power output. Usually the current in oscillator circuits are very low. But an inverter is designed to provide power.
• 

  [Prototype]

  Conqueror

  True cos the DC voltage got from a rectifier is 1/sqrt(2) times the AC supply voltage. So for the converse to take place you need the product of Vdc and sqrt(2) to get the rated voltage
  
  Let us hear if this is proper #-Link-Snipped-# do comment here buddy

  Not very much sure about this conversion. If you consider the voltage to be RMS, there's a one on one relationship between AC & DC i.e. 10V AC = 10V DC.
  
  But as lal said, you will not be able to derive much current using normal oscillator circuit. Its better to use an inverter, but building/buying one could be expensive.
• 

  Jeffrey Arulraj

  [Prototype]

  Not very much sure about this conversion. If you consider the voltage to be RMS, there's a one on one relationship between AC & DC i.e. 10V AC = 10V DC.
  
  But as lal said, you will not be able to derive much current using oscillator circuit. Its better to use an inverter, but building/buying one could be expensive.

  That leads to another question Supply we receive in our houses are rated 220 V AC what is it is RMS or 0 to peak
• 

  lal

  That is the RMS value. 240V AC supply at 50Hz is our standard.
  
  A bit of confusion though, I learnt it as 240V but now wiki says it is 220V. Some other sources say it is 240V itself. It is the RMS value whatever. Need to shed some light.
  #-Link-Snipped-# sir which is the right one?
• 

  [Prototype]

  Conqueror

  That leads to another question Supply we receive in our houses are rated 220 V AC what is it is RMS or 0 to peak

  That 220V is RMS itself.
  
  

  lal

  That is the RMS value. 240V AC supply at 50Hz is our standard.
  
  A bit of confusion though, I learnt it as 240V but now wiki says it is 220V. Some other sources say it is 240V itself. It is the RMS value whatever. Need to shed some light.
  bioramani sir which is the right one?

  Its normally stated as 220-240V because the power supply keep on fluctuating between those values, however, they ensure the minimum and maximum value are not violated.
• 

  solar morpher

  #-Link-Snipped-# use an inverter as others have said supply voltage of 220 V from mains is sufficient and current based on the life time you desire and the charging time you desire fix them That should do it
• 

  Ramani Aswath

  lal

  That is the RMS value. 240V AC supply at 50Hz is our standard. A bit of confusion though, I learnt it as 240V but now wiki says it is 220V. Some other sources say it is 240V itself. It is the RMS value whatever. Need to shed some light.
  #-Link-Snipped-# sir which is the right one?

  Inverters are basically power oscillators with wave shaping to get nearly pure sine wave. Good ones are expensive but better than normal grid supply. This is a basic article on inverters: #-Link-Snipped-#
  
  India won't be India unless there is some confusion. So, we have two voltages. Single phase domestic supply is 230V and three phase is 240V/415V.
  This table is quite useful and can be kept for reference:
  #-Link-Snipped-#
• 

  zaveri

  Thankyou all for your replies
  
  honestly speaking i don't think i can afford an inverter.
  
  but then how about this alternative : ?
  
  obtaining the power from the battery though an oscillator and then stepping up the voltage using a step-up transformer ?
• 

  Jeffrey Arulraj

  When a voltage is stepped up you will not adequate current in the op side
  
  This is cos more energy than the ip cannot be derived at the op of any device
  
  So if u step the voltage up the current drops in the op side causing the device not to work
• 

  Ramani Aswath

  zaveri

  obtaining the power from the battery though an oscillator and then stepping up the voltage using a step-up transformer ?

  That is what an inverter does.
  See if any of these do it yourself ideas will work for you:
  #-Link-Snipped-#
• 

  prashanth463

  sorry for this basic question, do we have a device that can amplify voltage and current simultaneously?
• 

  prashanth463

  sorry for this basic question, do we have a device that can amplify voltage and current simultaneously?
• 

  Jeffrey Arulraj

  yeah CE amplifiers do that but provide a phase shift But mostly this current amplification is not sufficient so we go for multi staging
• 

  prashanth463

  But ce amplifiers are good voltage amplifiers not current amplifiers right?
  Please correct me if i'm wrong
• 

  Ramani Aswath

  prashanth463

  sorry for this basic question, do we have a device that can amplify voltage and current simultaneously?

  If that can be done, the first law of thermodynamics will be violated. Output Power is always equal to input power minus power consumed by the device.
• 

  prashanth463

  Oh so now i understand, either voltage or current can be amplified so that the law is satisfied
  but sir i have another doubt, class A ce amplifier are good current amplifiers and as it is a ce amplifier it also amplifies voltage, so does this mean that this kind of amplifier voilate first rule of thermodynamics?
• 

  lal

  In amplification, an extra source other than the input signal is made use of. Power is added to the input signal from this extra source to amplify it. Input power thus includes the input signal power and the source power.
• 

  zaveri

  Conqueror

  When a voltage is stepped up you will not adequate current in the op side
  
  This is cos more energy than the ip cannot be derived at the op of any device
  
  So if u step the voltage up the current drops in the op side causing the device not to work

  
  so you mean to say that voltage is increased at the cost of current ?
• 

  ABCD ABCD

  Well, if you are using a incandescent lamp or something similar, then you can also power it up with DC. But, you need to look for the safe DC voltage that can be used.
• 

  zaveri

  mreccentric

  Well, if you are using a incandescent lamp or something similar, then you can also power it up with DC. But, you need to look for the safe DC voltage that can be used.

  i am going to use a small cabin fan. what about it ?
• 

  ABCD ABCD

  zaveri

  i am going to use a small cabin fan. what about it ?

  Then you can't use DC as is it. It works only for incandescent bulbs.
• 

  Ramani Aswath

  There are any number of DC cabin fans that will run on 12 V or 24 V battery.
  Here is one:
  Welcome to NATASHA
• 

  ABCD ABCD

  bioramani

  There are any number of DC cabin fans that will run on 12 V or 24 V battery.
  Here is one:
  Welcome to NATASHA

  Thats nice... zaveri, It'll be easy to use if you have an UPS(battery), or you can use a old car battery to run this(?).
• 

  Jeffrey Arulraj

  zaveri

  i am going to use a small cabin fan. what about it ?

  In a transformer and other static devices true
  
  But in the case of CE amplifiers the external DC serves as an input and that is utilised for increasing the op power of the signal
• 

  zaveri

  #-Link-Snipped-#
  
  Are you sure, that we can't run any A.C motors in this manner ?
  
  #-Link-Snipped-#
  
  what do you have to say to this ?
• 

  Jeffrey Arulraj

  Small cabin Fan's rotor need alternating supply to provide the varying flux required to drive them. So they cannot be driven using a DC supply I am sure about it friend
• 

  lal

  AC motors are called AC motors because they work on AC. These motors make use of a rotating magnetic field for their operation which can only be generated with the help of an alternating current.
  
  There is a type of motor called universal motor which can work on both AC and DC. Those are series wound motors. You can probably see it in a mixer grinder.
• 

  ABCD ABCD

  #-Link-Snipped-#,
  i'm sure about it. Else, is your DC source pulsating? But even that requires a circuitry. Better use a fan specifically made for DC. Acc to me, that's the simplest answer i can give.