I have step down 12-0-12 1Amp transformer input volts 220V and output 12V. As it is step up transformer Np > Ns. I was wondering if I can change it to step up transformer by reversing the input to secondary coil and output at primary coil.
Problem :
There are 3 wire at secondary coil. how do I connect those wire so that I can use 2 wire as input?(or 12V to both end)
My questions:
1.step down can change into step up transformer?
2.is there any power loss?(compare to step up transformer,actually I see there is some thin and thick copper wire binding in the transformer. Will this affect the power loss?
update:
I have 12V(Two 6V acid lead battery connected in series) I=16A(8A each battery) and i will add some resistor to get I=1A still working on the inverter part for AC current. The load is 9W CFL 100-300VAC.
Best Answer
Primary and secondary share the same core so, the main thing to consider is whether the core saturates more when driven backwards. Here's a sort of worked example: -
If the primary winding is 10 henries inductance, on 240V AC supply the current will be: -
\$\dfrac{240V}{2\pi f L}\$ = 76 mA.
Let's say the transformer had 1000 turns on the primary so ampere turns are 76.
The 12V secondary has one twentieth of the primary turns i.e. 50 and its inductance will be \$20^2\$ times smaller at 25 mH. Now, if you applied 12V AC to the secondary you'd get a magnetization current of: -
\$\dfrac{12V}{2\pi f L}\$ = 1528 mA.
Ampere turns are 50 x 1.528 = 76 (i.e. just the same)