Coils in series?

[Farlander]

Is it possible to connect step up transformers in series?  I have (2) 110V A/C to 220V A/C coils with heavy iron cores, if put together could they yield 440V?  One consideration is that I won't be using A/C, but pulsed DC.

[pese]

Jes you can do it
(fortunatly two transformers from same type.

you can also use this for 110 to 220 volt , for  double wattage (parallel)

[gyulasun]

Is it possible to connect step up transformers in series?  I have (2) 110V A/C to 220V A/C coils with heavy iron cores, if put together could they yield 440V?  One consideration is that I won't be using A/C, but pulsed DC.

Hi,

You also have to consider a possible problem the pulsed DC may cause: its DC content can bias the transformer cores on their B-H curve to a point where saturation may occur or the transfer may get nonlinear and this may or may not be good for your application.
Your transformers were probably designed for normal AC power transfer where the operation is symmetrical around the zero point of the B-H curve and using them at their rated power level saturation cannot really occur.
A remedy for avoiding the shift toward saturation in case it is not good for you when pulsed DC is involved is using capacitive coupling for the input pulses instead of direct one.

rgds,  Gyula

[Farlander]

So, by capacitive coupling, you mean installing a capacitor in series just before the coil...?  I have several large caps, 75V 1500uF.

By saturation, I'm assuming that once saturation occurs the coil will no longer output proportional to the input?  The output curve would begin to fall off and then remain constant at saturation, even with an increase in input power?

How do capacitors prevent the saturation effect?

[gyulasun]

So, by capacitive coupling, you mean installing a capacitor in series just before the coil...?  I have several large caps, 75V 1500uF.

By saturation, I'm assuming that once saturation occurs the coil will no longer output proportional to the input?  The output curve would begin to fall off and then remain constant at saturation, even with an increase in input power?

How do capacitors prevent the saturation effect?

Yes, in series with the coil.  This way the DC content of the pulse cannot bias assymetrically the core.

Yes, what you wrote on saturation.

Capacitors block DC and any saturation that might occur when you directly connect the pulsed DC to the coil will be prevented.

I notice, it all depends on how heavily or lighly you are going to drive the transformers. Saturation can also occur for normal sinusoid drive if the AC current is too high to drive the core off its B-H curve. In case of pulsed DC this overdrive can happen on one side of the B-H curve, depending on the DC pulse's polarity (this is where I wrote assymetrically) with lower drive current too.

For tranformers that are designed to carry some DC current besides the AC, a certain sized air gap is introduced in their core to withstand the amount of saturation the DC current would cause otherwise.

rgds, Gyula