Stator/Rotor alignment

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72Combat

72Combat

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Todays silly question: :roll:

Tri Spark 3 phase stator arrived today. Made a nice break from the flipping oil tank repair......russem russem...

I pulled off the old one and replaced it with the new one. However the stator sticks out over the rotor about 1/4" and the rotor is set back....I would have thought it should when viewed from the top ..parallel...(.I'd say birds eye view but with Kiwi's thats the view from underneath)

do I just file/hack the standoffs down to suit?

I spent 8-10 hours on it today...enjoying the strangeness on fractions on spanners and sockets......wires that change colour from one end to the other...... impossible to reach bolt heads..... :wink:
 
Either turn down the spacers behind the stator of purchase new one at the hardware store. I bought 3/8" wide spacers from our local store for $1.00 each. Bring a micrometer to make sure that the 3 that you get are as close to equal as possible. That being said, your system may be fine the way it sits but an 1/8" overhang is much more common.
 
Reports show only crude alignment needed to function adequately but worth peace of mind and a few more watts to center up the flux fields on stator coils. Spacing in/out is pretty obvious to do but if not centered requires a stout well aimed hammering to distort the studs better. If really into hi rpm use that flexes crank ends you can fudge some more rpm head room by knocking the stator downward and backwards a bit off static centering, as stator get slung into stator in 7to 5 o'clock area. No much issue till over 8 grand though.
 
The instruction sheet said .5 mm clearance around the rotor, I measured more on the 12 o"clock to 6 side and less on the 6 to 12 side. Is bashing the studs with a hammer a good idea???? Does the crank flex that much?
 
As far as radial centering of the stator studs, instead of an ill placed hammer shot, I put some nuts on the studs, cranked a 12" adjustable wrench on the nuts and bent it in direction wanted. Slightly more finesse than a hammer. Yes the studs will move.

Dave
69S
 
The traditional way is to bash it to center as moves all the studs same amount at once, the other way is open up the stator holes some but then leaves prone to shifting. Prying is also traditional way if too scared to handle a big hammer or only one stud at issue.

Crank don't flex enough to matter until over 7000 or so - and ya snap throttle closed so piston suction adds to the inertia holding crank middle up while aiming its ends down and back. Could ink the rotor and go for it and see if good enough as is or not.
 
ok to run it without the chain cover for test purposes....?
Click to expand...

Not only fine its wise to see what's happening running to know for sure.
Chain only needs oil for long runs at high load and speed. Belts should be observed opened too.
 
I've been running air gaps as low as .003" for perhaps ten years now with no ill effects. The battery almost never needs recharging even though I seldom exceed 3000 rpm around town--and I use Widder gloves in the winter. Smaller gaps mean higher output. Unless you run near the engine blood-line or have worn main bearings I've found that close enough is good enough.


Tim Kraakevik
kraakevik@voyager.net
Two Commandos
 
Yep closer magnets are to the induction copper the better but its luck of the draw what gap is possible. To say you set at .003" is not usable advice as ya can't change the stator ID nor the rotor OD, just center them evenly or not. Two ways to get more juice, more flux &/or more copper. I've a spare old rotor I'd like to try to implant super magnets in to see if worth while for more juice at low rpm. Super magnets has allowed the home windmill crowd to make their own alternators worth while. Will be tricky to adapt to factory rotor, may have to create a new one, maybe out of Al cut to hold magnets mechanically rather that screwed, welded or glued.
 
Rotor to stator air gap on Lucas alternators can generally be adjusted by backing off the mounting nuts, and moving the stator on the studs till the gap is uniform. Not really that good an idea to use a hammer on the studs, as its pretty much impossible to ensure the stator remains parallel to the rotor, once the studs have been bent by hammering.
 
Alas not all alternators can be centered by fiddling the mount spacers. Don't bang on each stud but on the mounted stator through its robust flux plates on all studs at once. A clutch or crank end nut, or chain break or belt unravel can jam up on stator and skew it. Pick method or weapon of choice to fit the situation.
 
Buttoned up the primary casing...new seal etc....having a cup of tea....thought I'd have a look at the NOC service notes again in more detail..... got to the bit about expoding rotors....nearly spilt my tea...Dilmah by the way....nice cuppa.

I took some pics but they were more general and I could make out the W they were on about.....
I could make out what looked like a date ...../72?

should I panic....or does it just join the list of things to worry about......scheesh and I thought my bevel drive Ducati was a worry.... :roll:
 
Problem was solved by welded version of rotors. Can check to see if any play or fracture detectable on outer casting on the inner steel bush and inspect seams of magnets exposed. Pretty much bad ones already filtered out over 4 decades for upgrade.
 
Just to add to your pensive sense of life with a truly factory Commando, one of the most spectacular flywheel explosion happened to a fella just letting it idle for warm up when a piece took out cases and broke car and home window across the street. How lucky do ya feel? Plenty just owning a Commando!
 
Why am I all of a sudden worrying about my '69 original rotor?

Dave
69S
 
You worry because you are wise hearing about what has happened to others no fault of their own. Can look at your case or any of us in two ways, one its tested proven to last over decades, or, its about used up and will blow on next ride.


This consists of the Lucas rotor (part # 54202298, which superceeds all the previous rotor numbers) and the Lucas stator (part # 47205). The rotor is the welded construction type rotor.
Click to expand...
http://www.oldbritts.com/11_068100.html
Stator/Rotor alignment
 
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