I know what he was looking for, Jim. That's why I said 'wade through
the 48V -> 12V models' - so he could get to the less common 12V -> 48V
models that he wanted. I should have made that clear. :-)
Telecom equipment is always spec'ed for ~54 volts. The battery strings
consist of 24 (occasionally 25!) cells. To keep them healthy over their
20 - 25 year warranty period (!), they are occasionally given an
equalize charge which can push the voltage up to ~56 volts. Of course,
during an extended AC power failure, the voltage can drop well below 48V
so the equipment has to function under those conditions as well.
Ed
Lux, Jim (337C) wrote:
On 9/25/09 11:23 PM, "Ed Palmer" <[email protected]> wrote:
Have you checked our favorite auction site? I saw some there by
searching for '12v 48v converter'. Wade through the ones that are 48V
-> 12V and there are a few that look interesting. One in particular
from Vicor looked quite attractive.
Ed
I think he was looking for 12V to 48V, which is substantially less common.
48V to whatever is quite common, since 48V is a standard DC bus voltage.
Of course, another problem is that the Z3801A doesn't use 48V. It takes more
voltage, from K8CU's site: The Z3801A is specified by HP (depending upon
model) as either a nominal minus 54 or plus 27 volt device. The best bet
is to keep the voltage at the nominal value specified by HP. This way any
out of specification internal DC to DC converters are satisfied, and the
units will perform normally. Reports from other users confirm this.
Mouser and Digikey both have a ton of DC/DC bricks with isolated inputs and
outputs. You can series the outputs (make sure you've got load resistors on
each one, and perhaps some diodes)
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