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Author Topic: Savage Salvage  (Read 20956 times)

z.monkey

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Savage Salvage
« on: December 13, 2010, 03:08:39 AM »
I got a small generator as salvage, uh not working.

So, Hey lets see what make this thing tick...

Its a 2 phase alternator with 20 stator poles divided into four quadrants...

FatBird

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Re: Savage Salvage
« Reply #1 on: December 13, 2010, 03:24:09 AM »
Thank you for sharing your salvage photo results.

Do you see any Brushes & Slip Rings?  I ask because I would expect brushes to be used to control the V or current in that rotor winding, thus controling the output.

Thanks.

.

z.monkey

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Re: Savage Salvage
« Reply #2 on: December 13, 2010, 03:29:36 AM »
Its a brushless AC design.  I don't quite yet understand it completely.  There are two small magnets on the rotor cores, and the coils on the rotor rap back around, isolated by a 1.5 Kohm resistor.  It must have some hidden rectifier diodes to generate the exciter current.  I'z dunno right now...

z.monkey

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Re: Savage Salvage
« Reply #3 on: December 13, 2010, 02:41:33 PM »
Its a 2 phase alternator with 20 stator poles divided into four quadrants...
I was wrong about this, its 30 poles on the stator, which means its wired like a 3 phase alternator.  There are two windings that come out to the plug, and the third is connected to a 10 uF 350 Volt capacitor.  This may be the regulating device.  The current in the third winding flows until the cap is full, then restricts flux on the other windings because the current is not flowing in the third winding.

I can't believe they made is so cheap.  An equivalent on at Harbor Freight is on sale for $119...

http://www.harborfreight.com/800-rated-watts-900-max-watts-portable-generator-66619.html

And that comes with a stinky 2 HP gas engine...

Just gimme the alternator, keep the stinky gas engine...

FatBird

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Re: Savage Salvage
« Reply #4 on: December 13, 2010, 05:18:11 PM »
It's amazing that they can sell them so cheap & still make a profit.  LOL

Judges

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Re: Savage Salvage
« Reply #5 on: December 13, 2010, 11:41:22 PM »
Keep us posted on this ,,,sounds and looks interesting,,but,I
Like stinky smelly little spark-plug engines I immediately think,,propeller,,
Have you found the Fault yet?
As I Say,,Do Keep us up on what your doing with it,Regards

Joe in Texas

z.monkey

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Re: Savage Salvage
« Reply #6 on: December 14, 2010, 12:54:05 AM »
Judge,

There was a lot of varnish in the combustion chamber, and I suspect the carburetor looks the same way.  This one sat around a lot, and ran a little.  Also the fuel line was old and cracked, leaking.  A good cleaning and a tune up would probably make it sing...

I do have a great appreciation for any motor, and this one is pretty neat for it cheapness.  It has an ignition coil which is activated by the magneto on the flywheel.  It has an Iron Cylinder with a Steel sleeve as a bore.  The head is Aluminum, as well as the rest of the castings.  Also the crank is balanced, with a 1 piece connecting rod to the aluminum piston.  Neat little motor...

But, I feel a need to do something different with this alternator.  There are some problems there too.  The nose shaft on the alternator gets press fit into the crankshaft, so I would have to modify the nose casing, and the crankshaft to have a nose casing, bearing and shaft that I could couple to something else, like a impeller...

I'll let it fester in the back of my brain for a while, and see what pops out later...

shylo

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Re: Savage Salvage
« Reply #7 on: December 14, 2010, 01:27:55 AM »
Great stuff Z ......I have a 3000w geny but it quit working ,it has a breaker switch in it do you think, maybe the switch is f@#d,.....because it stopped putting out juice but the breaker never kicked?........you seem to know alot more about these kind of things than most....thanx for any input,......looking forward to your future postes............shylo

XS-NRG

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Re: Savage Salvage
« Reply #8 on: December 14, 2010, 01:35:41 AM »
thats a classic 2 stroke 70cc driven design with forced air cooling.
It's output is between 600 and 900 Watts usually.
And they normally run at 3000 Rpm  :)

z.monkey

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Re: Savage Salvage
« Reply #9 on: December 14, 2010, 03:31:42 AM »
thanx for any input,..  shylo
3KWs, huh...  Could be a lot of things, and there are not many specifics to deal with...

Brushes, Windings, Bearings, or Corrosion, who knows?  You gotta take it apart to find the fault...

Remember to unplug it first...

z.monkey

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Re: Savage Salvage
« Reply #10 on: December 14, 2010, 03:33:18 AM »
thats a classic 2 stroke 70cc driven design with forced air cooling.
It's output is between 600 and 900 Watts usually.
And they normally run at 3000 Rpm  :)
If the secret is buried in the code, where is the code for this alternator?

XS-NRG

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Re: Savage Salvage
« Reply #11 on: December 14, 2010, 05:38:39 AM »
If the secret is buried in the code, where is the code for this alternator?

There is no code for that it's analog.
These types of generators do not use inverter technology there are some that do and they have a circuit board somewhere.
Also some are for welding in stead of AC.

Anyways you noticed the two small magnets on the rotor these generate a small voltage at startup which is known as the "floor voltage"
This is fed back into the coils and as the device speeds up the rotor's electromagnetic winding turns it into a strong electromagnet.
Speeding up it gets stronger and stronger and it also moves over the output windings on the stator so it starts to put out electricity on the socket.
This is all frequency sensetive so it is RPM related and if you do the math it runs at 3000 RPM putting out 50 or 60 Hertz you should be able to figure out how its wound and then u can understand the wiring  :)

Ususally there is also a 12 volts output to charge up car batteries and if so you will find a graetz bridge rectifier and a cap somewhere.

If they do not run it's usually the spark plug that needs some cleaning.
It's brushless so that cannot be the problem.

z.monkey

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Re: Savage Salvage
« Reply #12 on: December 14, 2010, 11:29:15 AM »
Well,

I was asking specifically about the alternator.  The rotor is two poles, and there are 3 phase windings.  These have a set of mathematical properties, which is code.  Number of windings per phase, and then also the winding scheme, more code.  If you look at the design process of the alternator itself, you need a specific size core to support your target wattage, and everything needs to be scaled accordingly, more code...

So, even though its analog, there is still code...

XS-NRG

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Re: Savage Salvage
« Reply #13 on: December 14, 2010, 03:50:28 PM »
Not digital. I/O

Judges

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Re: Savage Salvage
« Reply #14 on: December 14, 2010, 04:53:09 PM »
Yes,,,not digfital,,,,I/O.....

The varnish seems to ALWAYS work itself under the needle valve and seat,,,,if it has a different type carb with no needle valve nor bowl,,,then it is always those TINY screens,,,,can you imagine a screen so small that it will allow gasoline to pass but not water?,,Yep,,repaired several.

Joe in Texas