AC transformers

[Jason Wilkinson]

 Hi to all,  i have two transformers, one gives 11.8 vac and the other 14.6 vac  open circuit  measured with the same voltmeter. when the 11.8 is connected to the batt  through the rectifier the current to the batt is 7 amps  if i interchange the 14.6 transformer the current to the batt is only 4 amps i have checked the voltage on both several times  and it's always the same i seem not to be able to understand why the smaller voltage gives the larger current. The 11.8  transformer is larger in size

 Jason

[Flux]

"The 11.8  transformer is larger in size"

That is your answer. The large one has a lower impedance ( probably both resistance and reactance are lower).

Flux

[Jason Wilkinson]

THanks again  FLUX

 jason

[framistan]

The comment left by "flux" is correct,but i think this example will

help you understand what is happening.  If your battery was almost

fully charged, and only ONE amp flowed, then the higher voltage transformer

would deliver a little more amps than the lower voltage one.  .  However, since your example has a pretty well discharged battery, then the smaller transformer is delivering ALL THE AMPS it is capable of ( because like "flux" says, it is the

smaller)  However the larger transformer is capable of more AMPS.  

Just like in ohms law .... the load determines how many amps will

flow.  In the real world, the quantity of amps delivered to the load

is determined by VOLTAGE of the source... and RESISTANCE of the load,

and also the CAPABILITY of the source.  consider the ohms-law problem of

12 volts going to a 2 ohm load.  6 amps will flow, because 12volts divided

by 2 ohms is 6 amps.  but only 2amps will flow if the REAL WORLD power

supply is only capable of delivering 2 amps! hope that helps.... framistan

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