[Milsurplus] AC Power on Ships

[Bruce Gentry]

Bruce Gentry wrote:
> Glenn Little WB4UIV wrote:
>> On a military ship power is not referenced as is normal for shore 
>> stations.
>> Each side of the line is 50 % above ground.
>> If the ship is in battle and there is electrical damage that causes 
>> leakage to ground, the ship's equipment can still function.
>> If neutral is grounded, and there is leakage from hot to ground, the 
>> equipment quits operating.
>> In normal operation, the electrician or IC man of the watch checks 
>> ground indicators.
>> If one indicates that one side if a distribution buss shows a 
>> "ground", the electrician or IC man commences ground isolation.
>> When the circuit that is causing the problem is isolated, they will 
>> isolate the offending equipment and have it repaired.
>> Basically the distribution system is this way to increase reliability 
>> even with battle damage.
>>
>> Hope this helps
>> 73
>> Glenn Little
>> ETCS(SS) USN RET.
>>
>>
>>
>> At 06:18 PM 10/24/2010, J. Forster wrote:
>>  
>>> Hi,
>>>
>>> I was just asked about the AC line on WW II era ships. It appears 
>>> there is
>>> no neutral and the 115V 60 Hz just floats with each line 60-80 V AC 
>>> above
>>> structure.
>>>
>>> Is this correct and common or is there a fault?
>>>
>>> And, more importantly why would they do it this way?
>>>
>>> Best,
>>>
>>> -John
>>>
>>> =============
>>>
>>> ______________________________________________________________
>>> Milsurplus mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:Milsurplus at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>     
>>
>> ______________________________________________________________
>> Milsurplus mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Milsurplus at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>>   
> There are two other instances of "floating" ground familiar to me. 
> First, older paper mills here in upstate New York used it for the  
> same reason as ships. There were conspicuous boards with banks of 
> light bulbs on them monitoring phase equality and grounds in the 575 
> volt AC distribution system. A nice warm glow on all of them was 
> great, dark or bright bulbs indicated a problem even if everything was 
> running fine. The second application is diesel  locomotives. Stray 
> currents flowing through the bearings of the traction motors can cause 
> them to seize, resulting in the worst of wrecks. A relay monitors 
> this, and if it activates, the train must be stopped and the cause 
> found.  Certain defects  require  staying stopped, others allow the 
> train to proceed under  restrictions.     I have seen many Navy radio 
> equipments with the main power switch breaking both legs of the 
> incoming power,   making it easier to find the ground.    Bruce 
> Gentry, KA2IVY
>