Re: is this the correct piggy?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Steve Ward" <steve.ward@xxxxxxxxx>

Saturation is (Depending on how you want to look at it) a function of
voltage*time (the integral of voltage over time).  This V*s area for a
half-cycle of operation must not exceed some limit, or else the
transformer will saturate.  This is why higher frequencies can run
higher input voltages, and why if you run a 60hz transformer on 50hz,
you will have to derate the voltage input a bit.

You can also analyze it from the perspective of winding current, but
since current and voltage will be linked by inductance (ohms law), its
the same difference.

So yes, even over-volting a pigs primary (if the secondary was left
open circuit) would still saturate the core at the same voltage as if
the secondary was heavily loaded.

Steve

On 4/4/07, Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
>
>
>
> --- Tesla list <tesla@xxxxxxxxxx> wrote:
>
>  > Original poster: "David Rieben"
>  >
>  >  > Original poster: "J. Aaron Holmes"
>  > <jaholmes@xxxxxxxxxxxxxxxxxx>
>  >  >
>  >  > All that said, a number of folks (I remember
>  >  > specifically Aron and Justin of hvguy.com) have
>  >  > over-volted their 7.2kV pigs, i.e., by putting
>  > 240V
>  >  > across the 120V lugs.  This will make your 7.2kV
>  > pig
>  >  > put out 14.4kV, however it will do so only with
>  > great
>  >  > risk to your pig's health.
>  >
>  > Also,
>  > when the primary windings of a transformer are
>  > overdriven
>  > above their designed voltage rating to that extreme,
>  > the output
>  > voltage of the secondary does not continue to
>  > increase in a linear
>  > proportion to the primary's input once the core
>  > begins to
>  > saturate. This will occur in most transformers when
>  > the input
>  > voltage exceeds about 140% of the designed voltage
>  > rating.
>  > With MOTs, which are made with as little iron in the
>  > core
>  > as possible to hold down the weight and the cost,
>  > you'd better
>  > make that about 105%! Once the core begins to
>  > saturate, any
>  > further increase in input voltage will cause the
>  > unloaded current draw
>  > to increase dramatically, almost in a "J" curve, but
>  > the output voltage
>  > of the secondary will no longer continue to increase
>  > in proportion to
>  > the increase of the input voltage. Operating in this
>  > fashion makes for
>  > an unhappy transformer ;^(
>  >
>  > David
>  >
>
> Hey, David!  So, what you're saying is that it's tied
> to core saturation, then?  Or am I misunderstanding?
> But isn't core saturation more a function of power
> throughput in an AC transformer?  Will simply
> increasing the voltage lead to saturation, or wouldn't
> you also have to load the transformer down beyond its
> rated power throughput?  I thought the latter was the
> case, but my mental model of a transformer is
> over-simplified, I'm sure!
>
> Regards,
> Aaron, N7OE