Regards,

Forum user…….RSMike

I remember (barely) from my Navy days as a shipboard electrician that for our shore power connection we had 3 3Ø 4W 400A cables that had lugs at one end and large pin connectors at the other, though there was a threaded sleeve at the pin connector end to keep them fully engaged. Kind of a pain to drag around, but relatively trouble free otherwise.

Radar

Electure, the Islands are not immune to hack work by any means, just like how other places are not . A lot of the resorts do not hire electricians for thier mantainence people, but instead will advertise in the papers for "handy person" or "mantainence worker needed". Local 1186 used to have the hotels pretty well covered, but that has eroded away over the years. And the result is in your pictures.

I thought USS Arizona sank in 1941 at Pearl and was now a War Grave. That first pic can't be the original ship, can it, or am I mistaken?

Alan

He meant USN Missouri, BB63.

Arizona is 100% below the waterline....

We entered the war with one, terminated it with the other.

macmikeman- not my pictures. Pictures are from RS Mike

Someone is paying attention. You win the prize. It is the Missouri. I didn't think anyone would notice. I actually typed it wrong....noticed it and then decided to leave it to see who's awake....

RSlater,
RSmike

P.S. The Arizona Memorial is a must see and difficult to forget.....

Added during edit....
Also forgot to mention. The Arizona is not 100% below the water line. One of the gun turrets and a few other portions of the ship are still above water. Oil still exits the ship....about 2quarts per day. I watched as tiny black beads came up from the hull and broke the surface.... They say it's the ship crying for her dead. Very humbling experience; enough to make you cry.

Sorry to get off topic.

[This message has been edited by RSmike (edited 01-16-2006).]

I too will second those cables as being a beast to handle. Once a bunch of morons just pulled them back in a rats nest, instead of rolling them back on to the reels right next to them. Took 15-20 guys to un-tangle. Once on the reels they are enough to seriously tax a fork lift... Usually these go back to a transformer hopefully not too far away.

BTW what is that crapola above the cabinet? Ropelight I'm guessing?

I wonder how much a trip to Hawaii on the USS Arizona would cost?

And how long will it take?

Mike, I'm a surfing kiwi and having done the "Pearl Harbour /Arizona Memorial Cruise" whilst visiting Oahu in 1987, I was also wondering how you photographed the deck of the Arizona !

Come on kids...read the thread....There's a reason this was on the Arizona...One mistake, which I chose to leave in my post, and you guys are ruthless.

E57....there's a mess of lighting on the ship that is run as you noted. Same stuff that you see around every construction site. Little yellow baskets protecting a zillion watt bulb.

Anyone know if this big stuff is 400Hz. I noticed a bunch of power related buildings near the shore power box. I was wondering if they were doing some fancy stuff to convert it. I'm quite unfamilar with the miltary and how they use and abuse power systems.....

RSlater,
RSmike

RSmike:

My guess on the 60 to 400Hz conversion would be with the use of motor-generator sets or rotary converters (Basically a huge motor shell with the motor and generator windings on the same stator, IIRC).

We had only one rotary converter on our entire base and it was rarely used. I was told that besides the incredibly annoying whine it made (As compared to the "Dash-60" jet turbine generators?!?) it was also incredibly inefficient.

Why convert to 400Hz ? What are the advantages of this ?

Also, sorry Mike, I didn't mean to sound like a gawking tourist. Even though its been 20 years since I laid a wreath at the Arizona in Pearl its still very fresh in my memory.

A lot of military applications use 400Hz to save space and weight - the transformers are a lot lighter.

If I recall, the big honking plugs were called "Joy" connectors. I think it was the manufacurer's name. I was on submarines, we pulled 4 400 amp 3phase cables into the escape trunk where the recepts were. Ours were threaded. You used a huge spanner wrench to turn them. Ugh. Bad memories.

The Navy used the 400hz sets on the computer systems. It was a method to speed up computing speed.

I know 400Hz is used on aircraft because xfmrs and motors need far less iron and copper, and this results in weight savings that in aviation applications are more important than the lower energy efficiency involved with such a high frequency.

I wasn't aware that 400Hz was used on ships. Space savings would seem to be a good reason.

It is not possible to get 400Hz from 60Hz using a rotary converter. They require different shaft speeds. If the second frequency is a multiple or submultiple of the first, you can use a shaft or a direct drive motor-generator (well, after adjusting for the slip). I guess they must use belt- or gear-driven motor-generators, or VFDs, or something like that.

Any aviation workers out there?

[This message has been edited by yaktx (edited 02-01-2006).]

I occasionally need 400Hz power in the lab where I work. Converted from 60Hz by a special rotary converter made by Georator Corp.:
http://www.georator.com/ProductRotaryMotorGenerator.php

The company in that link appears to disagree with that statement.

The first unit shown is indeed a belt drive, but the next *one is common shaft*.

I recall that a while back someone invented a motor/generator with "rewritable poles", in other words, through some sort of control it was able to shift the magnetic location of its poles actively while running. I'll try to dredge up a link...

edited text between *, the last item on the linked page is actually a line isolator.

[This message has been edited by mxslick (edited 02-02-2006).]

Fascinating... it has an induction motor, but will produce 400Hz from either 50 or 60Hz? How is this possible? If you had a universal or permanent-magnet motor, you could vary the motor speed, but induction?

Written-pole motors... yeah, I've heard of those. Never seen one, though. I read on the web where they are being used in irrigation, since you can get them in just about any Hp and they run on single phase.

[This message has been edited by yaktx (edited 02-02-2006).]

Years ago, I worked in a building on a RAAF base that had 415/240VAC 50 Hz, 115VAC 50Hz, 208/115 60Hz & 208/115VAC 400Hz (the 60 & 400 Hz came through supplied through rotary convertors). These were all disconnected in the early 1990s & only the 415/240VAC 50 Hz & 115VAC 50 Hz remains now (fed from a pair of rather large transformers under the floor-about 100 Kva each)

When I was in the USAF as a ground support equipment technician, I worked on a lot of motor generators that are single shaft 60Hz motors to 400 Hz generators. Many of these motor generators were older than I was at the time. Some of these were called the MD-1 or -2 or -4. They ranged in size from 15 KW to 75 KW. When I was stationed At RAAF Lakenheath in the U.K. we changed over to 50Hz to 400HZ equipment from the older 50 to 60 Hz then 60 to 400HZ units. One piece instead of two is easier to maintain and works better.
400HZ power is standard on aircraft almost every where in the free world. some of the reasons are above.

400Hz is also used for radar and com. gear. (Aviation and Military) From what I understand, it offers a much smoother wave form when rectified for those uses with a higher available current. (as the alternation spends a lot less time at lower potentials)

FYI 50 and 60 will give you a kick in the pants, 400 will burn you in the proccess.

As for generator shaft speeds, they run roughly about the same general speed as 50/60 gennie sets, they just have more magnetic fields on the stator so the armature crosses more fields per RPM. Or at least the sets I have worked with... I assume a convertor (I haven't used any) would operate just like a rotory phase convertor, instead of just adding a phase, add a bunch more fields to cross.

Sorry for dragging up a year-old topic, but we (I work for a subcontractor of American Airlines at PDX) use a solid-state electronic converter, manufactured by FMC technologies. It converts standard 480V 60Hz to 3-phase 110/208V at 400Hz via a 6-wire connector. Most of the systems on the aircraft run on the 400Hz AC, but there are a few things (like lighting) that run on 28VDC. I'm not entirely sure what the sixth conductor on the plug is for, but I supsect it's probably a second ground.

Here is the converter: http://www.fmctechnologies.com/AirportEquipmentServices/GroundSupportEquipment/GroundPower.aspx

Here is the connector: http://www.usairmotivegse.com/imagenes/producto/3989R676XXE7198.jpg

There are other manufacturers for this equipment as well.

I was just told that many European industrial locations (mostly metal work) use 200 Hz and 300 Hz for hand tools like angle grinders! That's for two reasons, at that frequency they can use lightweight 3ph asynchronous motors that are basically indestructible, and the synchronous speed is much higher.
I saw that used in a smallish company that makes turbines for small hydro plants. All tools use green 3+Earth CEE connectors, the most common system is 265V 200 Hz.

We are a steel engineering company and we have 300Hz 3 phase distribution for grinders. The reason we use them is that they dont slow down when you apply pressure. Sturdy - maybe they are often away for repair. Effective - extremely. I recall that they are 200V and are Bosch but I cant find any info on the internet about them. We are upgrading the system in a few weeks to MCB and RCD setup for personnel protection.

I will get some pictures on Monday of the system.

400hz comes from 2 onboard MG Sets and it is used for Synchros and Servos. The 400hz gives greater accuracy transmitting that kind of angular signal. If you want to know more check out the NEETS Navy Electricity and Electronics Training Series. I was a navy ET and we used the 400hz for radar and communication antennas. The folks who really knew it inside and out were the IC Men (Interior Communications) and there are quite a few in our trade.

I was a gun fire control tech. in the Navy. Our weapons radar equipment was fed from two 400 hz mg sets. It was 40 years ago so I'm not sure about the snchro-servo system we used, but I believe they were 120/60. I still beieve that us FT's had the best job on the ship.

Hey, those cables are the shore power cables I was asking about in the NEC forum a few days ago; they're still very much in use! We use those cables for temporary power connections in shore facilities, too.

Due to increasing reliant on COTS gear, 400Hz equipment on ships is getting rarer and rarer. There is still quite a bit of 400Hz gear, though, but most of it now is simple economics: rather than develop 1 component for aircraft and another for ships, it's easier to provide 400Hz power on the ship and keep commonality.

Navy is migrating from MG sets to solid state frequency converters onboard ships, but I'm not aware of any plans to rip out the old MG sets quite yet- there are cost savings in reduced maintenance for new installs, but not enough to warrant outright replacement. Savings in space, weight and moment are also important, and a place where the solid-state units shine. There is one bonus to the old MG sets- they act as rotary UPS, too, and can ride out short power hits.


[This message has been edited by SteveFehr (edited 03-03-2007).]

From johno12345:

Continued....

Hey, that 3-phase socket looks extremely like the weird old one I posted some time ago!

It does, I did think about it at the time. We have a variety of the same type with different pin configurations.