Can I wire the outputs of two separate transformers to get twice the voltage? I have two separate, identical transformers from neon signs. Both put out 6000 volts at 30 mA. I would like to use 12000 volts for my project.
Electronic – Does combining two separate transformers double the voltage
seriestransformervoltage
Related Solutions
Two small turn count transformers would be smaller than a single transformer in the sizes I need
That's unlikely to be true for the following reason. The size of the transformer is largely dictated by the power it has to transmit through its windings and this, in turn, dictates the core size. Any ratio transformer is permitted provided there is enough room to cram-in the wires. Using two transformers to transmit (say) 1W of power means both have to be rated to pass this power and this means that they will together, occupy twice the volume of one transformer.
It's another matter if you can't get hold of a certain size transformer but there is always the option to rewind the secondary.
Here's a 100:1 step up transformer that is 6.6mm x 6.6mm: -
Do you need one smaller than this?
Flyback topology is one of the common schemes for SMPS of less than a few hundred watts because of the simplicity. These equations give the first order calculation of some parameters you ask for:
$$ I_{peak} = \frac{V_{in} t_{on}}{L} $$
Energy stored by the transformer per period: $$ E_{L} = \frac{1}{2}LI_{peak}^{2}$$
Power transferred: $$ P = \frac{E_{L}}{t_{period}} $$
t_period would 10us for 100KHz. t_on is the switch on time, assuming 50% duty as a starting point, it would be 5us.
- The peak current must be less than the saturation current while accounting for input voltage variation and tolerances plus safety margin. The peak current does not translate directly to output current through the turn ratio.
- When wired in parallel, the output windings should be capable of giving 9A.
- When wired in series, the output windings should be capable of 3 times the voltage @ 3A.
- For SMPS and flyback SMPS in particular, the turn ratio does not translate to actual input voltage vs output voltage.
I don't know how to say much more within a page or two. Possible resources would be some manufacturers' sites such as TI's. There are usually loads of application information. Pick SMPS ICs that seem to meet your requirements and some of them would have online calculators of recommended circuit arrangements.
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Best Answer
In theory, yes. providing you get the phase correct. It would effectively be a 6kV - 0 - 6kV transformer.
Would I do it - NO. There is a good chance that the winding insulation will break down and the magic blue smoke will escape - even assuming a 50% safety margin they are not designed for that amount of voltage.