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Onan MDJE 7.5 1978 Possible Burnt Windings


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  #11  
Old 03-10-2018, 02:57:21 PM
Vanman Vanman is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

One potential advantage that generator windings have over those of an induction motor is that a motor started across the line undergoes heavy magnetic stresses, vibrating the windings every time it is started. A generator, on the other hand, only experiences those conditions when it is called upon to start a large motor. Probably not every time it runs, and maybe never, depending on the application.
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Old 04-15-2018, 05:37:51 PM
yachtgilana yachtgilana is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Thank you for all the suggestions. They have been helpful.

It was fun to find which wires were which, this is a double delta 518 wound stator.
There are 12 wires coming out, but the numbers have all come off! So the wife and I worked this out like Sudoku...

1+6=L1
2,4,7,12 all link together in a box
8+10=L2
9+11 joined
3+5 joined

I measured and did all the tests today, and found the rotating rectifiers, main rotor, exciter rotor and stator all perfect, maybe 15% off spec.

The main stator was down to ground on 6,3,8,11...So out it came.

I got a quote from a very professional looking rewinding shop, for rewind and encapsulate and bake for $240.00 so I'm going to send it in. I have rewound alternators before, and it was fun, but this time I have too many balls in the air.

There are some pics on our web page, gilana.org
here http://gilana.org/44_mallorca2/03summ05/summ05a.htm
and here http://gilana.org/89_4years/4years.htm

Pictures are more fun...

Will come back here and post my results...
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Old 04-15-2018, 05:49:01 PM
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Love those TIGHT places that a boat has to work on the equipment. Got to make use of every last square Millimeter! Good thing you are a trim and fit guy! Is there a DETROIT diesel in your yacht?
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Old 04-15-2018, 05:52:35 PM
yachtgilana yachtgilana is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Yessir. That is a 3/53 Detroit, also made in 1978 like the genset. Beautifully made equipment both of them!
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Old 04-26-2018, 09:05:45 AM
snotter snotter is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

The quote you got is outstanding. What is the name of the windshop? I'm interested in learning of the results when the time comes.
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Old 04-26-2018, 11:29:38 AM
yachtgilana yachtgilana is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Hi, I was also surprised. We will see. They were, however, rewinding a 190V DC motor from a compressor from a military submarine, and that is a critical machine. They are ISO 9001 also. Here is a link to the rewinding shop.

http://www.centralderebobinadoltda.c...tros-servicios
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Old 05-08-2018, 10:19:15 PM
yachtgilana yachtgilana is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Hi

I went to the rewind shop today to get my stator back. I am very impressed with the work, rewind and encapsulate in hi temp epoxy $241.60

I have too much work to do right now with the boat hauled out but I will get back here on progress soon.

In the meantime here is a pic of the stator after I put it down for a rest, its a long walk with that on my shoulder.
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Old 05-09-2018, 12:45:00 PM
maillemaker maillemaker is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Wow, I was looking at your web site last night! You guys are serious ship people!

Steve
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Old 05-09-2018, 02:44:54 PM
FLracer FLracer is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

That's a big hunk of copper! The next time I visit my Aunt&Uncle in Majorca (he keeps his yacht in Pollenca at the YC there) I will have to look you up. They used to keep it in Alcudia but moved it to Pollenca a few years ago. I was there last Sept. and had a great time. Nice part of the world. Brian
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Old 05-09-2018, 04:14:42 PM
yachtgilana yachtgilana is offline
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Default Re: Onan MDJE 7.5 1978. Possble Burnt Windings

Hi, We were in Mallorca when we joined Smokstak. We are now in Cartagena Colombia. On the hard at Ferroalquimar.com
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