[R-390] OT - Transmission lines - local

Randy and Sherry Guttery comcents at bellsouth.net
Thu Feb 24 18:07:37 EST 2011


On 2/24/2011 4:27 PM, Les Locklear wrote:
> Interesting story about 4160 volts.
> <...snip...>
> We worked up to 660 volts, nothing higher,
> that's what they were for. Nasty stuff!
>
Sea story (but unfortunately a true one): Aboard my last 
ship (that sounds better than "only" ship - but then again I 
was aboard 53 months)- the highest AC voltage we had to deal 
with was 440 - tons of current - but 440. I've seen 
electricians pass their fingers down a row of fuses - 
looking for the one that had "juice" across it... Usually 
the 120 didn't get much reaction - but if they caught a 440 
bus - usually they'd let out a cuss word... but then just go 
on and replace the fuse.   DC was another matter... There 
was a 500VDC bus that carried sizable current here and there 
- never knew what it was for - though some of the old timers 
claimed that during combat in WWII - welders could plug 
their stingers directly in and do on the spot repairs.  I 
can't imagine welding with that much voltage and current 
(the conductors were in the multiple aught size).  What was 
really dangerous, though was the propulsion bus...  Three 
2875 horsepower 16 cylinder diesels turning generators that 
put out "nominal" 500VDC @ 2000Amps.  Those three generators 
would be placed in *series* to drive the four electric 
motors that actually turned the shaft (actually two shafts - 
the above is a description of one engine room - the other 
was identical - except one drove the port prop and the other 
drove the starboard prop.). In 1972 the entire ship was 
"re-engined" (main propulsion and Ship's Along Sides 
generators were 8 General Motors Model 16-645E5s; Ship's 
service were 2 General Motors Model 12-645E5s) - the 
generators and motors reworked,  and all of the switch gear 
updated, etc.   While testing the main propulsion generators 
and switchboard under full load (talk about some big 
resistors - the load cells on the boat deck could dissipate 
some 6 million watts -- we could push them very nearly to 
that!) - there was some "issue" with one of the switches 
(imagine a switch able to switch a generator in / out of a 
loop with 2000+ amps and approaching 2000Volts *DC*!).  One 
of the yard workers was trying to watch the mechanism while 
the switches were being thrown - and as he was leaning 
around the back edge of the switchboard - he apparently lost 
his balance - and without thinking - just instinctively 
reach out to steady himself...   When the body bag was 
passed up the access ladders - we only needed one hand to 
pass it along...

Be careful out there...  That stuff is called nasty for a 
reason...

-- 
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com



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