ciao a tutti,
I have few chargers that need the transformator replaced,
I digged a while on the forum and on some more sites, like Jacque's one but I'm a little confused
what the specs exactly are ? primary 220 V, secondary 16 V and VA ???
thanks for help, Alberto
Classic Chargers
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01-17-2011, 09:15 AM
01-18-2011, 03:13 PM
Hi Alberto,
The secondary voltage of the transformer must be between 6V and 9 V. Regards, Kees
01-18-2011, 04:42 PM
ciao Kees
01-18-2011, 10:04 PM
Quote: The condenser will charge to the peak voltage (RMS * sqrt(2)). Yes, the diodes will drop the voltage about 0.7v each. (If using a full-wave bridge rectifier, about 1.4v.) Your 220v:6v transformer might be close enough. 6v would be about 8.4v before the diode drop. So a full-wave bridge would provide about 7vdc. If you supply it with 240v on the primary you would get about 0.5v more on the secondary. Or if you use a half-wave rectifier you could get another 0.7vdc but might need more capacitance.
01-19-2011, 03:52 AM
I think I will desolder a transformer from a good working classic power supply and see how much is the secondary value
01-21-2011, 04:40 AM
Ciao Alberto,
Yes, in the past (2007 i think) I have done measures on the Classics transformer 82002A.
You can easily confirm that with a multimeter. That's it ! I will open a working adapter this WE for you and measure the voltage at the Xformer's secondary. That said, my HP calc site has become too huge (too much data) : errors are certain. Thank you all to help me correct them!
Edited: 21 Jan 2011, 9:21 a.m. after one or more responses were posted
01-21-2011, 09:02 AM
In Tony Duell's article on classic chargers he shows the rectified output to be 16V (I think this is open circuit voltage, as the cap is rated 15V). Therefore I would guess a transformer with a secondary voltage of ~10V AC would suffice. HOWEVER, in another thread Tony warns "The output voltage of this transformer is designed to fall under load, in a specified way" (I would hazard a guess that this is to reduce the stress on the power transistors as the load increases). So a standard transformer may not be the best solution.
01-21-2011, 09:17 AM
Alberto, I have done (at the risk of my life ....) a video of the measure. Took a 82011A which is safer : I have only 2 hands (with the 82002A, it's not easy to keep the 110-220 slider in place !!) Result is : 12,5 V AC at the secondary (unloaded). See : checking a 82011 battery charger
Edited: 21 Jan 2011, 9:27 a.m.
01-21-2011, 11:26 AM
Thank you very much !!!! |
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