On 13 Mar 2006 11:02:58 -0800 firstname.lastname@example.org wrote:
> Someone mentioned Bell using jet engines for central office power
> backup. I'm kind of surprised at this. The electric companies use
> them for summer supplements. They are very expensive to run, but can
> get up to speed very quickly. I believe the phone companies use more
> conventional diesel engines to power generators. If there is a power
> failure, central office battery has enough capacity to keep things
> going for a while, more than enough time to power up a diesel engine.
> The jet engine has the advantage of being smaller.)
Every "emergency engine" I ever saw in a telephone building was a
conventional diesel engine. My father-in-law was shop foreman for a
company that sold and service large earth moving equipment in Enid,
Oklahoma, and from time to time they were called upon to routine the
auto-start emergency engine in the Enid c.o. It was a conventional GM
diesel engine like those used on earth moving equipment and
Offices with 24-hour coverage had larger diesel engines that were
started manually. Both auto-start engines and those started manually
were tested once a week by pulling the commercial power and making
sure that the officde transferred properly to the emergency engine
and, in the case of auto-start engines, that it started properly.
As Lisa says, the batteries would carry the load for some time. The
batteries always carried the load, with commercial power or emergency
power being used to float the batteries and charge them continuosly.
Usually the emergency engines, at least in offices with manual start,
were tested at 7 a.m. on Wednesdays and run for an hour carrying the
load. If you happened to hit dial tone or ringing tone at that time,
you could hear a slight blip in the tone as the load shifted from the
usual ringing machine running on commercial power to the backup which
ran from the c.o. batteries.
C.O. batteries were very large compared to the usual auto battery you
think of, and existed in large numbers.
As to Servel refrigerators, the patents (and perhaps the name) were
purchased by ArkLa Gas (originally Arkansas-Louisiana Gas Company).
It his now combined with another large gas utility and has a double