I am trying to see if it is possible to drive two coils on a transformer at the same time and extra the combined power from a third coil. :)
Here are three cases of transformer operation:
two coils on transformer 1:1 turns ratio, coil 1 driven at 30V/1amp
three coils on transformer 1:1:1 turns ratios, coil 1 and 2 driven at 30V/0.5Amps
three coils on transformer 1:0.5:1 turns ratios, coil 1 driven at 30V/0.5Amps, coil 2 driven at 15V/2Amps
Will all three cases give the same output on the third coil, and will they all work the same assuming that the two driven coils are driven properly in phase?
You can do what you propose, but be careful! If the two primary source voltages are not exactly in the ratio 2:1, then you will have a circulating current through the two primaries that could result in excessive dissipation in the primary resistances.
three coils on transformer 1:0.5:1 turns ratios, coil 1 driven at 30V/0.5Amps, coil 2 driven at 15V/1Amps
will it also work this way:
three coils on transformer 1:0.5:1 turns ratios, coil 1 driven at 27V/0.5Amps, coil 2 driven at 15V/1Amp
If the dutycycle is increased on the coil1 to compensate for its lower voltage, or is there another better method to handle this mismatch? I was thinking that maybe with enough feedback to the controller you could implement some form of PWM interleaving between the two driven coils, or maybe another form of PWM control, so that whichever driving coil is "weakest" will turn on after and off before the stronger driving coil. Any ideas on the best ways to drive a transformer with 2 coils like this?
The application I am thinking of for having two or more driven coils on a single transformer is for if you have two independent power sources you can feed them through one transformer and combine them into the output power source.
not to say it has a lot to do with what you're experimenting with but, have you ever looked at Magnetic Amplifiers? It's very interesting to note that even though they are old in design, they are still being used in various ways today.
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"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
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Hi--- Check the internet for "Micron Transformer" or "impervitran Transformer". Their catalog has a short formula/section on how to size a transformer for an inductive load or multiple loads at the same tome or various combinations.
Woops, hit send by accident. Anyway, it's a real easy formula. Basically, if I remember right (after using it faithfully for 27 years and now 6 years not using it into retirement), it is:
That the required VA of the transformer is equal to the Square root of all of the following:
Square the holding current of coil #1 then add it to the Square of the holding current of coil #2 and on and on etc, then take the SQ Root of the sum of all of them.
then add the inrush current of each coil (if you have it) and again square tose, add them and take that Sq Root.
Add the two together (holding plus inrush currents and take the Sq Root of the total.
Multiply the result by the voltage and you have transformer VA required to take not only the holding current, but take also the inrush current.
Try that under each conditions of multiple coils.
It's basically the "Square root of the Sum of the Squares" method and has been an industry standard for electrical work for mamy many decades.
My old brain is straining to remember exactly, but do check that site to make sure I remember the formula right.
Micron's phone is For questions or assistance, call our Technical Support Group at 800
664-4660
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I don't see their transformer sizing formula on the innternet, but order their catalog on "Control Transformers" and it will have it in there.
Or simply call for technical assistance.
Going to be---i finger typist and this took over 1/2 hour
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