EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: twtb on November 11, 2022, 04:58:16 pm
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Does somebody know where we can buy the Spitznagel SPK 03115159 transformer?
The primary needs 22V, which makes it very hard to find a replacement.
The vendor doesn't help unfortunately.
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How critical is that voltage? It is safe to apply 22 VAC to a 24 V primary winding, if the resulting secondary voltage is appropriate to the application.
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Not super critical, but even then it's hard to find
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In your original unit, what is the secondary voltage of that transformer?
You can run a transformer in the reverse orientation (e.g. 220 V primary, 24 V secondary transformer will deliver approximately 220 V when 24 VAC is connected to the 24 V "secondary" winding).
Note that this is approximate, since transformers are not rated directly for voltage ratio, but for voltage delivered into rated load current.
Also, you should not apply more than the rated voltage to a given transformer winding, since that can saturate the core (even without load current).
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In your original unit, what is the secondary voltage of that transformer?
You can run a transformer in the reverse orientation (e.g. 220 V primary, 24 V secondary transformer will deliver approximately 220 V when 24 VAC is connected to the 24 V "secondary" winding).
Note that this is approximate, since transformers are not rated directly for voltage ratio, but for voltage delivered into rated load current.
Also, you should not apply more than the rated voltage to a given transformer winding, since that can saturate the core (even without load current).
Well, it is written in the photo - 22V primary, 2x15V secondary, 3VA ...
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Oops—I only looked at the second photo.
Good luck finding such an odd set of winnings, even approximate.
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tried https://am-transformers.com/product-category/spitznagel-alternatives/ ?
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I think I have tried almost everything now. Even 24V to 2x15V transformers are impossible to find. Will need to throw the machine away and buy another one.
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The transformers themselves are broken?
Is there a chance to botch in different transformers and supply the unit from 230V?
Or maybe you find a mains transformer with separate 15 and 24 secondary windings and use this to convert from 22 to 15V.
What are the supply voltages generated by the board?
Maybe you can replace the transformers by DC/DC converters.
Just don't call it botch work rather than re-engineering.
I replaced a broken custom transformer of a frequency counter by a combination of small SMPS modules and DCDC converters to supply all required voltages.
What's the unit anyway?
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The parts after the transformer create 4x +12V (7812) and 4x -12V (7912). Wondering if it really requires them to be separate. Can't I just supply 1x +12/-12V?
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We don‘t know, only you can find out. But why should they have made the effort to have the supplies four times if not necessary?
If you want it to be nice, make a piggy board that comes in the place where the transformers were.
With rectifier, smoothing cap and a couple of DC/DC converter modules either regulated or unregulated ones whether you keep the linear regulators or skip them.