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Re: Telettra 48V power supply




These sound like they may have been originally intended for telephone
central office applications, as 48V systems are very common there.  If
that's the case, however, be aware that these systems are positive
ground, -48VDC power systems.  This could have significant implications
of the positive (ground) end of the power supply is tied to the
equipment case.  Also, take the color of internal cables with a grain
of salt as well.  "RED" may be "hot" (-48VDC) and black may be
ground (positive terminal.)  This might also be unexpected.

Some of the other pins may be used to help equalize the power supplies
when they're ganged together in a rack in parallel to increase capacity.
In many applications, these things are configured as chargers for a
-48VDC battery plant, with a -54VDC float voltage for charging.

louie


> I have found several 48V power suplies. I was willing to use them with a
> recently purchased Z3801A. This unit itself, is not labeled outside as
> 48-60V, but others exactly the same are. I think it is really a 48V unit.  
> The problem is that those units were used in vertical racks forming part
> of microwave communication gear and they have a double line connector in
> the back: 'a' with 1+6+1 pins and 'b' with 4+4 pins. I have opened them to
> try to see were are 220V AC and 48 VDC connectors, but they are far too
> complicated for me. Does anybody know if this an standard connector?. I
> have put in the WWW photos of it.
> 
> http://kender.es/~edu/Telettra-Supply-rear.jpg
> http://kender.es/~edu/Telettra-Supply-rear-low.jpg
> 
> http://kender.es/~edu/Telettra-Supply-front.jpg
> http://kender.es/~edu/Telettra-Supply-front-low.jpg
> 
> http://kender.es/~edu/Telettra-Supply-left.jpg
> http://kender.es/~edu/Telettra-Supply-left-low.jpg
> 
> http://kender.es/~edu/Telettra-Supply-right.jpg
> http://kender.es/~edu/Telettra-Supply-right-low.jpg
> 
> 	Best regards and thank you for interest
> 
> 	Eduardo/EA2BAJ
> ----
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