va calculation for transformer

[hiren_dave]

hi.

i required a transformer of 24v for 2A load. i saw a transformer with 24v and 2va. so i don't understand that what is va? can i use 2va for 2A load?

 

[vedagarbhamsandeep]

hi.

i required a transformer of 24v for 2A load. i saw a transformer with 24v and 2va. so i don't understand that what is va? can i use 2va for 2A load?

2VA is the power rating of the transformer.

Sure, you can have a 2A load but make sure the voltages match else if you connect a 12V to your 24V transformer, it may blow !

 

[mailus]

no it's wrong........
your requirement 24V, 2A so you need 48VA (24V*2A) transformer.
but 24V 2VA means you get 0.08A (2VA/24V). so it's not suitable for your requirement....

 

[jeffrey samuel]

power is equal to VI

here p=2VA
and V=24V
so simple math I is lower than your need

 

[hiren_dave]

i got it...

thanks....



can i use two 12v transformer in series and use 24v ?

 

[mailus]

Yes it will work...but care is needed because both transformers primary winding direction And secondary winding direction must be same to get output.otherwise you get 0V output(12+(-12)=0). Best way you find a transformer 24v it is the best...easily available

 

[hiren_dave]

ok..

if i want to generate 24v dc with 1A from 230v ac how can i??? any direct ic available or not??

 

[mailus]

Two major methods available to get dc.
1.Transformer
Transformer is cheapest method.
2.smps
Switch mode power supply(smps) is costly.
One more method is available very very cheapest but it's dangerous method by using capacitor step down the Ac voltage and rectify the voltage. But it will not handle higher currents

- - - Updated - - -

Best choose transformer... buy one transformer.. For what purpose you need DC supply.

 

[zsolt1]

hi,
for simple 24V/1A suply : 30 VA transformer (230/24), bridge rectifier+filter cond., LM7824 (with big radiator) or any series stabilizer with discrete components ....

 

[jeffrey samuel]

if you are planning to convert the op of transformer into dc use rectifier (bridge should do ) then a filter and a zener diode as voltage regulator to regulate the op voltage

 

[papunblg]

ok..

if i want to generate 24v dc with 1A from 230v ac how can i??? any direct ic available or not??

can i use two 12v transformer in series and use 24v ?

1. You can connect secondary windings of two 12V 1A of in series. If you get 0V output(12+(-12)=0) as mailus said, then simply reverse the connection of one
of the windings.

2. Do you have a 12V 2 Amp 12-0-12 transformer? Its end to end voltage is 24V. Use with a bridge rectifier

 

[jeffrey samuel]

direct copling may build small laging in voltage due to indutive reactance so there is a need of a cap couplig between the two transformers