I think I can answer this. The early ships you refer to were Steamers. DC was used in conjunction with batteries for all ship electrical power especially lighting. In the event if they had to shut down the boiler, or a malfunction, they still had electrical battery power to call for help and emergency lighting. Ship radio communication used the DC and a dyno motor to generate high voltage.
Later technology of course uses auxiliary diesel engine generators
Last edited by KF5LJW; 07-17-2012 at 03:29 AM.
So what was used to convert to 120/240V 60Hz which was still used for most of the electronics and other equipment.
For what it's worth, the conventional (oil) powered aircraft carriers like I was on, main power was 400Hz. The nuke carriers main power is 1000-something Hz, (1022Hz?).
400hz power distribution is used on aircraft carriers because they service and start aircraft which use 400hz starters and generators due to the significant reduction in weight and size realized from the reduced amount of core iron required. This dates back to WW2. Also avionic repair shops on board have 400hz power distribution. I am unfamiliar with 1000 hz distribution.
There is emergency battery power and inverters for emergency lighting and critical casualty equipment.
Nuclear powered vessels I am familiar with have a 450 vac/60 hz 3 phase and 120 vac/60 hz 3 phase main power distribution systems. The newer carriers have 4160vac 60hz 3Phase distribution and auxiliary transformers to step it down to lower voltage distribution.
The nuclear reactor and its supporting systems (motors, motor operated valves, solenoids etc) all are 60hz components just as they are on shore based nuclear power plants. I spent 37 years in nuclear power and employed many ex-E6 navy electrical techs. I am not current with todays technology as I retired 10 years ago. If anything my guess is they would tend to go to higher and higher voltages and not higher frequencies. 11kv and 13.8kv for larger motors is getting common place in land based power plants. You havent lived until you have heard a 25,000hp motor start across 13.8kv line.
Space station power plants are going to very high frequency same as modern switching power supplies, but that is a very different environment. Terry K9TW
Real simple they did not convert before WWII. Nothing used 60 Hz. In those days there was no Cell phone, MP3 players, video games, Blow dryers, or toys to play with.
Originally Posted by KM1H
Aircraft, ships, and even some modern data centers use 400Hz because generators and transformers are much smaller and lighter. For passenger vessels and modern ships and aircraft use 60 Hz converters, or 60 Hz generators.
I stand corrected, thank you! Sorry I crossed my voltages and hertzes. It's the very high voltage that stands out.
Nuclear powered vessels I am familiar with have a 450 vac/60 hz 3 phase and 120 vac/60 hz 3 phase main power distribution systems. The newer carriers have 4160vac
60hz 3Phase distribution and auxiliary transformers to step it down to lower voltage distribution.
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I am not saying you are wrong about 1000hz I just am not familiar with it. One problem with going higher in frequency is you have to worry about Inductive Reactance (XL) affects in the miles of cables and not just IR copper losses.
I have heard that airline industry is looking at high voltage DC distribution to meet the ever increasing power demands with large passenger air craft. They are always concerned about weight. If they go to high voltage DC they can use inverters to produce the required AC voltage. The advantage would be they could use only one conductor and use the air frame as the return like we do in our cars. This would eliminate the weight of half of the required copper cable. All very interesting. Terry K9TW
The only thing I can think of is that perhaps AC generators were not yet in sufficient supply... somebody check me on that.. when did Westinghouse lose the power generation battle? There isnt a real advantage to running DC, but the 220 would allow for smaller diameter wire for a given load.
Maybe that's it. It's been a long time, but something about the stability sticks in my mind... I was a navigator, so as long as the compass and Loran worked, I was happy. It didn't mater how they worked, just that they did...
Originally Posted by N2EY
They are not anymore or less stable than there 60 Hz cousins, they are just much lighter and smaller which is real important on planes and ships. The downside of 400 Hz is there are higher voltage losses, but is not much of a problem because planes and ships do not have real long wire runs, or can be sent out high voltage then a small transformer to step it down if a large load is required some distance from the generator.
Originally Posted by N2EY
Are you sure about that? That would cause all kinds of voltage loss problems, not to mention fairly easy to detect and give away the sub position.
Originally Posted by KB4QAA