Re: Tranformer efficency VS Frequency

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "rheidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

I'm confused!! did you test switching or transformer systems.There is no
similar relationship."Real" large core transformers have a sharp low
frequency drop off and a wide slope high frequency role off. Special
switching power supply transformers are made for a specific frequency band
and drop off both sides of resonant frequency.Some "cheep" small core
transformers also have a limited band width.
  Robert  H 

> From: "Tesla list" <tesla-at-pupman-dot-com>
> Date: Sat, 09 Mar 2002 15:29:37 -0700
> To: tesla-at-pupman-dot-com
> Subject: Tranformer efficency VS Frequency
> Resent-From: tesla-at-pupman-dot-com
> Resent-Date: Sat, 9 Mar 2002 15:40:43 -0700
> 
> Original poster: "Alexander Rice by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <alex-at-rices.myip-dot-org>
> 
> Hi All
> We did an eperiment in physics today which investigated the effects of
> operating frequency on the efficiency of an ordinary laminated core
> transformer.
> Using a power sign gen we input current at varying frequency into the
> transformer, power in and power out was calculated from the product of
> Current and 
> Voltage at each side using ordinary multimeters (not true rms ones)
> frquency was 
> varied from 2Hz to 2Khz.
> 
> Heres the rub, i was expecting to see an increase in effiency as frequency
> increased, bearing in mind the way switched mode power supplies work, what
> we actually 
> found was that effiency peaked sharply at almost exactly 50Hz and dropped
> off sharply 
> either side - which puzzled me. My theories are - transformers really do
> this, maybee 
> it is somehting to do with the thickness of the laminations and induced
> eddy currents 
> OR our meters are at fault - DOES ANYONE HAVE A BETTER EXPLAINATION?
> 
> This does have a relevance to tesla coils - wouldnt it be great not to have
> to lug a 
> great hunk of iron and copper when you want to run your coil - maybee we
> can harness 
> the SMPSU's out of the newer breed of microwaves - maybeee this will be the
> 'next big 
> thing' in coiling
> 
> a mildly confused
> 
> Alex
> 
> 
> 
>