[R-390] OT - Transmission lines - local

[libbysales]

440 ?... no single AC fuse in this set up is  or has 440 volts potential to 
ground or neutral,  440 volts AC is the phase to phase resultant voltage, 
the single fuse would represent the product of the Sq root of 3 or 254 vac 
or approx ..mac/mc

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From: "Randy and Sherry Guttery" <comcents at bellsouth.net>
Sent: Thursday, February 24, 2011 5:07 PM
To: "Les Locklear" <leslocklear at cableone.net>
Cc: "R-390-List" <R-390 at mailman.qth.net>
Subject: Re: [R-390] OT - Transmission lines - local

> 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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