[Patrick Turner]

Phil Allison wrote:

"Ian Bell"
Phil Allison wrote:

Indeed. However, I would have expected the transformer to attenuate
noise in the 1Hz region


** Complete insanity.

Ordinary power transformers attenuate nothing coming in unless it is over
5 kHz.

** Complete fallacy.

** No - it is TOTAL FACT.

Transformers by definition have a zero at zero Hz.

** Got nothing to do with *VARIATIONS * occurring in the AC supply voltage
!!!!!

They have a pole at some frequency determined by the transformer
inductance and the source and load impedance.

** Complete drivel - there is no such pole as (un-gapped) transformers have
no defined primary inductance value. Core saturation is what limits an AC
power transformer's ability to work at lower frequencies than 56/60 Hz.

This must be where you made you IDIOT assumption that ordinary transformers
remove low frequency variations on the AC supply.

Try monitoring the 230 volt AC supply voltage on a DMM and see it jumping
around by up to +/ - 5 volts all the time.

I shall

** **** off you arrogant, know nothing ****ing IMBECILE.

I think he wants to learn though. I doubt he will accept your travel
recomendations or be perturbed by your colourful character description.
And perhaps, like so many of us, he has a lot to learn because like us
he doesn't know everything; maybe all the group can learn from us giving
more advice on what he should be trying to see, but for confusinous and
wavatious signal vexations.

In principle, I agree with you about the perfectly lousy way
transformers can pass 1Hz sine waves.

Bmax is often 1.2Tesla in any normal PT if designed for industrial use,
or maybe 0.8T for good audio amps. Consider a 240V primary winding.

The B is proportional to the applied winding voltage and inversely to
applied frequency.
So at 1Hz, a B = 1.2T would occur when the applied voltage was about
4.8Vrms. Iron isn't very linear though. Certainly, if you tried to apply
240V at 1Hz to a mains tranny, the iron would saturate badly and heavy
currents would flow and the fuse would blow. At such low F, the winding
inductance has a reactance that is very low, and the winding almost
works like a resistance equal to the resistance of the primary winding.
I suspect the OP has yet to investigate fully the operation of
transformers to see the limits of their operation. I recommend he hasten
to his work shed and CRO to teach himself about how trannies work, and
armed with books written about the subject, lest he fill his head with
bull**** concepts that don't describe what is happening as they are
described in the right books.
Its electro magnetic understanding that is required, and that is always
a difficult for so many...

Patrick Turner.



..... Phil