TELECOM Digest OnLine - Sorted: Re: Is Your Telephone AC Power Dependent?

Re: Is Your Telephone AC Power Dependent?

T (
Thu, 25 Jan 2007 20:10:35 -0500

In article <>,

> On Jan 22, 6:51 pm, T <> wrote:

>> Around here they don't bother putting backup power at most cell sites.
>> When Nextel put one of their cell sites on the building we're in we
>> offered them a tap off our generator but they didn't want it.

> The typical power "board" for a cell site consists of an AC-to-DC
> rectifier system that changes the 240VAC commercial power to +24Vdc
> needed for the equipment. Almost always, a string of twelve 2V VRLA
> batteries is provided for backup. A common size for the battery string
> is 1040 Ah (Amp-hours). The actual back-up time is dependent upon the
> load being drawn by the cell site equipment, age/condition of the
> batteries, ambient temp inside the cell site, etc.

The funny thing is, the generator puts multi-phased 480VAC which means
you could tap off 240VAC no problem. Oh well -- constant vs. 12 hours.

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