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 Post subject: Tech Question from Ebay transformer
PostPosted: Mar Sat 16, 2019 3:05 pm 
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"Windings can be combined to create a multitude of voltages.(.636 volts AC= 1 volt DC combining the 2 26 volt windings will give you 90 volts DC)"

Is this right? (26+26)=52/.636 => 81.8 (??) With a bridge, capacitors and/or a choke?

https://www.ebay.com/itm/Transformer-for-building-battery-eliminator-for-your-vintage-antique-radio/223449378175?hash=item34069eed7f:g:d2sAAOSw~gZcXx8-


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 Post subject: Re: Tech Question from Ebay transformer
PostPosted: Mar Sat 16, 2019 5:39 pm 
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Makes no sense. 52 volts RMS is ~73 peak. That is the DC voltage that you get with 100% rectification efficiency. Even if the efficiency is 90%, that's a bit over 63 volts. The 0.636 factor looks like the average value of a sine wave, which is irrelevant.

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Tech Question from Ebay transformer
PostPosted: Mar Sat 16, 2019 6:23 pm 
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Generally voltage is figured as 52v x 1.414= 73.52v, factoring transformer impedance, usually a little less with load.

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 Post subject: Re: Tech Question from Ebay transformer
PostPosted: Mar Sat 16, 2019 8:21 pm 
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Actually, the typical transformer is speced with a stated load current, so the max with no load is even higher......but that transformer is not going to produce 90 VDC, regardless

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Tech Question from Ebay transformer
PostPosted: Mar Sat 16, 2019 9:51 pm 
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pixellany wrote:
Makes no sense. 52 volts RMS is ~73 peak.


I was thinking along the same lines, just wanted a reality check. Except I'm thinking it's 52V peak/peak => 38VDC max! :?


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 Post subject: Re: Tech Question from Ebay transformer
PostPosted: Mar Sat 16, 2019 11:16 pm 
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Dave Allen wrote:
pixellany wrote:
Makes no sense. 52 volts RMS is ~73 peak.


I was thinking along the same lines, just wanted a reality check. Except I'm thinking it's 52V peak/peak => 38VDC max! :?

??--a transformer voltage---or any AC voltage---is normally stated as rms. 2 windings, 26volts rms each = 52 volts rms

If it were 52 P-P, thats 26 peak, and the DC voltage approaches that with no load

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"Measure voltage, but THINK current." --anon.


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