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Gregor

Charging stator

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Gregor

@TractorheadHave you ever rewound a charging stator? What size wire would you use?  Thanks  Greg

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Tractorhead

 

Yap, i did my Moto Morini about 8 or maybe 9 years ago when i reworked the Engine.

Sold her about 3 Years ago to a Morini Collector, who use her regular

it still works with no troubles since.

 

Do you have a pic of your Stator?

 

There are several requirements to estimate the results - (or even calculate them.)

But i do it mostly just by estimations about the result, what was close to equations, but saves a lot of Time 😎

 

what is the required Voltage and Amperage you like to have,

how many Coilposts are there in the Stator, they can be used to coil winding?

and how many Magnets in the Flywheel?

 

Will search for the Pict.

 

Aah, here we go, found the Picts...

 

CB731ACD-75A9-4D2C-AEA5-91689EA890DF.jpeg.f19b377d908ab1f48e0b202109ceb9d2.jpeg

 

Ho i must do that in that limeline.. 

 

C4F5B0BF-DC4D-47A5-8059-28971435CB27.jpeg.dc233186b2ce838d27b8d8f18b48eda4.jpeg

 

And the reworked Stator rewound with 1mm wire by different turns each coil.

 

I will check if i find my winding system again

( don‘t tell my Wife i had stolen her dark Red nail polish...) 😎

It was needed for a good cause..

Edited by Tractorhead
Found the Picts

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Gregor

This stator is off a Kohler K-181 , 8HP. I bought just the bare motor. No idea what it came from. There are 18 coil posts. All I need it to do is keep a 12 volt battery charged, on a battery ignition, K-181, with electric start. 

I don't know how many magnets there are, I will have to pull the flywheel to find that out.

Is it important that each post has the EXACT same number of windings on it?

If the stator is good, what would the ohms reading be, from one end of the coil to the other. I estimates it had 30, to 35 feet of wire on it.

 

 

20210414_084201 (2).jpg

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pfrederi

Some 1\K-181 stators did not have wire wrapped on every leg...For a 15 amp stator 0.1 to 0.2 ohms

 

 

 

stator.JPG

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Tractorhead

It depends a little on the liked results.

 

you have at all 18 Posts on that stator, what can result in a simple AC Generator

or also in a 3 Phase Generator like Motocycles have.

 

 

For a Pure AC Genny, i would try 18 or 20Windings from post 1 to post 18 with a Wirediameter of estimated about 1mm.

That should result in a something about 10-12A coil.

If you use each second post, i would increase the coils to 24 Windings, to result in a higher low RPM Charge.

Edit:

I forgot to mention, each 2 post shall be wound in opposite direction to the post before.

 

 

 

For a 3 phase Genny you need each third Post must be winded in a row.

That means you have to wind 3 times 6Posts, but just the next must be 2 posts away from the last winded one.

Each Post shall be fine with a 24 Windings at 1,2mm Wire.

 

This results in 6 open Wires, they be connected on one side all together to result in a triangle connection.

with that Stator you can use a Motocycle rectifier/ regulator.

The overall result is a higher efficency Charge coils.

 

This are not exactly calculated Values, just estimated, but they shall result in a usable charge.

Edited by Tractorhead
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Tractorhead

@Gregor

you be right with your estimations.

 

However, i calculated it to get a better Feeling for your Work.

By using each 2. Post you need a Wire diameter of 1,25sqmm and a 32 turns on each Post to result in 14A at about 19V

that make it easier to recoil, but if you like the max. amperage at idle, use each post.

That is a hard doing, i remember i just rewound the Charging coils 5 times i guess until they be as clean as on the Pict.

Allway‘s stretching the wire a little the coilwire between your fingers ( not nails) than turn by turn.

It was a 2 Day‘s job at least to finalize all the Coils, 

with finishing the complete harness i spent 3 Day‘s at all.

 

to get it that clean aside, use a little plasticfork and push the wire as close as you can together.

you remember at the last coil, here it is more important on a high current coil to supress eddy currents.

 

after complete recoil, check it out before covering it finally by a insert and running test,

your Voltmeter should display about 18-19V AC  on mid RPM’s, than disassemble the whole stator

and use Epoxy glue to fix the Coils at the End.

When all rewinding is finished, check that there is absolutely no short to the ground ( Stator itself).

the given resistance should be about 0,2 -0,3 Ohms between the final connecting leads and high to Stator.

 

Before winding the bare Metal, be sure on this Amperage to clean the Stator as good as possible and 

prepare the whole Metal with an non conductive heat resistant paint first.

You can use i.eg. Brake caliper paint what is up to 300*C heat resistant, because you don‘t have any plastic insulations there.

The double the wire diameter, the more raises the eddy currents and parasitic components.

That results in higher Temps on the Coil on higher Loads.

Also check, to get a heat resistant insulated copperwire like for motor Coils.

They be better prepared to resist the thermal stress.

 

 

Like @pfrederi Paul mentioned, you don‘t need each Post, except you need urgently the maximum charge at Idle.

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Gregor

Hmmmmmm   Maybe I can build a machine....:confusion-confused:

 

The wire I ordered.  .0469 diameter

Edited by Gregor
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Tractorhead
3 hours ago, Gregor said:

Hmmmmmm   Maybe I can build a machine....:confusion-confused:

 

The wire I ordered.  .0469 diameter

 

Sqmm or AWG?

 

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gwest_ca

.0469 inch diameter = .001728 square inches = 1.114559 square mm

.0469 inch diameter = 1.19126 mm diameter = 1.114559 square mm

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Gregor
6 minutes ago, gwest_ca said:

.0469 inch diameter = .001728 square inches = 1.114559 square mm

.0469 inch diameter = 1.19126 mm diameter = 1.114559 square mm

:confusion-confused: Are you saying I need different wire?

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Tractorhead
4 hours ago, Gregor said:

:confusion-confused: Are you saying I need different wire?

 

Should be fine, results in little less Current so maybe reducing by app. 1-1,5A less in maximum estimated.

While be little smaller you may can increase few windings more at each post to get higher idle voltage.

 

 

Recharging on a VRLA Battery, what i prefer for our purposes is depending on time.

A pure Lead Acid battery is in my World out of the race, and on VRLA a Quickcharge was restricted by the battery itself.

For short Term uses a AGM Battery had definitely some benefits while it has faster charge abilities.

But AGM also needs mostly a higher charging Voltage what most standart regulators prevent, 

they be fixed in Lead Acid Voltage, 13,8-14,4 what works also for VRLA batteries fine.

AGM should normally be charged at 14,6V to reach 100%, on 14,4V they be just loaded to 85%.

depending on Brand and quality of the battery they can be last or they give quick up.

 

That should result:

if you like to use this tractor only for a short term uses ( like just quick pulling a Trailer from here to there)

a combination of an higher Charging voltage and more current is absolutely more senseful,

but short term runs are more worse for the Engine life.

 

On regular uses like mowing or having a Joyride, i prefer the combo VRLA Battery with an usable Amperage

and a little higher idle Voltage. So you can use even idle phase i.eg when free up some areas before mow and 

Put thing back on their place after mow to recharge and accept a little less charging Current.

That is especially in Winterservice while snow plowing or blowing with lights a big Advance.

Here the Time is your friend at recharging. To have a little reserve in idle is never a fail.

So let do the Charge regulator it‘s job and regulate the Voltage in high RPMs down to something about 14V

 

 

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Tractorhead

I did today a recalculate at all, depending on few unknown in the Equation.

i still don‘t know how much Magnets are in the Flywheel.

So i just start in my unknown equation with an estimation with 4 Magnets to have a foundation,

also for the Magnetic Flux i use a basic magnet with a good usability.

you should get between 80 - about 100 Watts out of 10 Coil posts.

 

To do this you should need 10 following Posts, winded in CCW direction, each in same direction.

That means you begin at the first Post by winding in counterclockwise with 26 Windings than to next post,

each of the post have to have 26 Windings at all with a Wirediameter of 1,2mm.

by use 34 Windings, the overall Voltage should reach 17,8V on 2500RPM and 12,4V at 1200RPM about,

what means you have sensefully usable Charging power at 1400RPM.

 

The real result shall be somwhere 6,5 til 8,5A depending on the Quality of your Magnets.

Happy Winding.

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Gregor
3 minutes ago, Tractorhead said:

To do this you should need 10 following Posts, winded in CCW direction, each in same direction.

You are saying ALL posts should be wound in CCW direction. On the old coil, they alternated. CCW - CW - CCW - CW. All 18 posts.

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Tractorhead
23 minutes ago, Gregor said:

You are saying ALL posts should be wound in CCW direction. On the old coil, they alternated. CCW - CW - CCW - CW. All 18 posts.

Depending on the magnets in the Flywheel.

The winding induction results by north / south poles on the Magnets in the Flywheel.

So i can just oracle.

 

But if they where before cw, ccw, cw, ccw.... i would do it the same Schema again.

The magnets in the flywheel that is a unknown in my equation, as i allready mentioned in my last Post.

👍

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