[Gllug] [OT]fire at redbus?

[Chris Bell]

On Wed 16 Jun, Christopher Hunter wrote:
> 

> 
> I recall a similar event at the BBC (BH) at a Christmas some years ago, just 
> prior to the Royal Speech - public supply failure, and blocked diesel 
> generator exhausts, so no power!  Broadcasting continued by means of a 
> battery-powered OB unit.....
> 

   Yes diesel generators do soot up if they are run off-load, a huge standby
generator was running off-load at Wembley for the live-aid concert and had
sooted up by the time the mains fuse failed.
   You can not run a standby diesel permanently connected to the mains
unless you can guarantee that it will remain in sync with the national grid
at all times, even if the local mains fails for a while. Nearly sync is
definitely not good enough.
   Another possible problem is that diesel generators are difficult to
control in real use with a non-resistive load, so should be regularly tested
powering the real load. There can be some very nasty surprises if the diesel
starts hunting, with the frequency and voltage fluctuating wildly.
   Modern switch mode power supplies can be more tolerant than the old
transformer + series regulator, neither type will stand lots of over
voltage, but ordinary mains transformers designed to run at 50Hz look like a
dead short at 45Hz, and then you find out how many hundreds of fuses have
failed.

-- 
Chris Bell

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