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Why 60HZ in marine environment?

Why 60HZ in marine environment?

Why 60HZ in marine environment?

(OP)
The Britsh Empire (50HZ) once ruled the seas. So does anyone know why the ship and ship/shore power supplies are now always 60HZ. I understand it is a Nato standard for war ships... Does anyone know when it became a world wide standard.

 

RE: Why 60HZ in marine environment?

Perhaps because the US used to be the biggest shipper to Europe?

Or because the US Navy/merchant marine kept the British Empire afloat a while back?

Those would be my guess once you toss in those historical aspects.

Oh and toss on that all generators and motors are 20% smaller in 60Hz versions so why continue the mistake made on shore out into space constrained ships too?  

Keith Cress
kcress - http://www.flaminsystems.com

RE: Why 60HZ in marine environment?

My guess is that vessels were electrified earlier in the US than in the UK. And, as the saying goes, the winner takes it all.

I worked onboard a coal fired steamer back in the mid-1900. We had DC onboard...

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Why 60HZ in marine environment?

Gunnar

You're so last century. :)

RE: Why 60HZ in marine environment?

All of the above reasons...and one particular reason of note as well.  Submarines have nifty sonars that listen to machinery induced noises, typically these show up as a 3rd order harmonic.  If you radiate at 150 HZ (i.e. 50 HZ machine) you sound like a Soviet (errr Russian) warship--not so good if you are a NATO warship and you are targeted by your fellow NATO warships.

This all really came to be a codified "standard" when the U.S. launched Nautilus.  The Nautilus was operating at 60 HZ, she was first, and that pretty much formalized what had been evolving as a standard up to that point.

In a perfect world you would use aircraft frequencies (i.e. 400 HZ) throughout the ship--much smaller equipment.  Submarines do use 400 HZ but only for special applications--it is just too expensive to buy industrial motors at off-nominal frequencies...

RE: Why 60HZ in marine environment?

I understand that the naval use of 60Hz is a NATO standard.  As the US is the larger partner...

So all naval bases give 60Hz shore power, hence the use of frequency changers in the UK ports to give 60Hx power from 50Hz mains

RE: Why 60HZ in marine environment?

Prior to WWI there was very little electric service on the ships - aux power was mostly steam or human.  WWI through the Depression didn't see much construction (1923 Navy Treaty was scrapping big warships, for example; later not even merchant ships were being built in the early 30's since trade went downhill.)

WWII war construction was concentrated in the US, and the US could only supply 60 Hz generators, and 60 Hz motors followed since they were also available.   Very, very few comparably ships were made in England since most of the raw material would have to get shipped in on shhips already built.  US Navy ships standardized on 60Hz, the Nautilis and other 50's and 60's ships followed that standard.

US merchant shipping construction died after WWII, and everybody either re0used WWII left-overs, or built them overseas to US drawings and spec's.   The new overseas yards (Japan and Germany and Denmark for example) were rebuilt with US-provided stuff, so they tended to use material and spec's that could be connected to the frequency used on the shore power connections in the yard.

 

RE: Why 60HZ in marine environment?

US was dominant in numbers of ships and $ spent to outfit NATO piers. Cities liked the fleet to come calling, and once in port, the US Navy doesn't like to stay on ships power, so crew is liberated to run-amok in port. It was "If you build it, (or allow us to build it), we will come"

 The commercial US fleet is miniscule by comparison to other countries flagged vessels, but most commercial ships didn't care much about shore power. They took care of business and moved on. There are still many 50 Hz ships out there and this is all being re-thought for a different reason. In an effort to clean up the air around port cities, more and more ports are mandating shore power capabilities. I am in a quandry right now as to what voltage to go with for next ship design. Frequency will be 60Hz, but there is quite a mix of voltages out there and I am not sure when or what a standard will settle out being. Navy has 460/480 predominantly, but many commercial ports are 6.6kV. I may end up with both capabilities.   

RE: Why 60HZ in marine environment?

(OP)
We have just completed a port upgrade with 66.kV distribution and 460V shore side connections. 2 x 11kV 50HZ/6.6kV 11kV 2MVA motor-generators for supply  

RE: Why 60HZ in marine environment?

There are ships out there that run on 50Hz, QE2 for example.

Generally equipment is smaller and lighter at 60Hz so a big plus in on a platform.

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