> > Having said that, I do love the hum and breeze from
> > a decent MG set. As a first year apprentice I used to
> > sneak off and spend time in the number 2 substation,
> > with the wind blowing my hair from the big motors (each
> > was car sized), watching the little dials move as the
> > set compensated for the 1000A DC feed to the cranes,
> > dreaming that all that power was mine... Geeky or
> > what? ;o)
>
It reminds me of when I used to maintain a Microwave Relay Station. This had
what we called a Continuity Set. The incoming Utility Supply powered an AC
Motor whose shaft extended out to an Alternator. This powered the  Station
Electric's. However, between the AC Motor and the Alternator was a DC Motor
which was powered from a battery bank.

Under normal operation the AC Motor powered the Alternator which powered the
station. In the event of a incoming mains failure the DC Motor took over the
driving of the Alternator until the Diesel Generator started up and
stabilised and this was then connected to the AC Motor and the DC Motor
switched Off. As far as I can remember, the regulation of the DC motor was
by the field winding, this is in the days of Relay Logic after all.

One day we had a failure of the Utility Supply. All relays clicked in and
out as they should have except the one that started the Diesel Generator. We
were alerted when the continual background low pitched whine started to go
lower in pitch. The problem was solved by dashing to the Power Room and
applying a well placed kick to the control unit front panel.

The following month was spent filling out reports on why we needed to
replace every Klystron and TWT in the Station.

Happy Days, It was pre Monty Python and I don't believe William Gates III
had even been born then, Life was so much simpler :-)

Chris

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