Alternator Rotor Machining

[concours]

Well yes, but then why is there a 0.010” difference?

It can only be either intentional, or unintentional. Both are impossible if dimensions and tolerances were followed !

But you’re kinda right really, unless someone measures a significant number, all we know is that ‘some’ are failing, and for reasons unknown…

I have nothing further on that.

What if the failures entirely unrelated to dimensions, or clearance?

 

[Fast Eddie]

I have nothing further on that.

What if the failures entirely unrelated to dimensions, or clearance?

Well that’s exactly what’s being discussed here. Are the failures electrical, mechanical, or a combination of both?

We do not know.

On mine I addressed both. And have no failure. So that’s good for me, but not for our root cause problem identification !

 

[commandofastback]

I have ordered a complete new set of RM24 14,5 Amp stator, non exploding rotor and a new mosfet regulator from Hollandnortonworks.
They will also turn down the rotor by 0.020" for me.

Now that i disconnected the melted stator, one of the bullet connectors fell off !!

Also i now rubbed off the melted plastic off the old rotor and i cant see any scratches or grooves from physical contact.
So for me it looks more like dodgy connector + overworked Boyer Power Box than a clearance issue

 

[kommando]

I fitted a Lucas full fat 14.5A 3 phase stator in the mid 80's, never an issue with charging.

 

[Fast Eddie]

I fitted a Lucas full fat 14.5A 3 phase stator in the mid 80's, never an issue with charging.

That’s a ‘real’ Lucas stator, so dimensions and tolerances would presumably be correct.

What do you have it connected to in terms of rectifier and bulbs etc?

 

[commandofastback]

I fitted a Lucas full fat 14.5A 3 phase stator in the mid 80's, never an issue with charging.

As mentioned elsewhere, the new ones are only branded Lucas but made by Wassell

 

[kommando]

What do you have it connected to in terms of rectifier and bulbs etc?

Over the years it's had zener's (triple pack as per T140) with original rectifier, modern rectifiers/regs. Bulbs have been hi power 60W halogen and now LED's. Always run lights on so it had the full range of different setup's and survived them all. It was bought when Meriden went to 3 phase as that was the upgrade path I followed so that I had the best setup. I would not touch Wassell replica's, had one of their rect/regs go back with a constant leak to earth that drained the battery.

 

[YING]

View attachment 124228

Thank you Nigel,
I made a similar bracket and will give it a try.
Appreciate your picture.
Mike

 

[YING]

I fitted a Lucas full fat 14.5A 3 phase stator in the mid 80's, never an issue with charging.

Over the years it's had zener's (triple pack as per T140) with original rectifier, modern rectifiers/regs. Bulbs have been hi power 60W halogen and now LED's. Always run lights on so it had the full range of different setup's and survived them all. It was bought when Meriden went to 3 phase as that was the upgrade path I followed so that I had the best setup. I would not touch Wassell replica's, had one of their rect/regs go back with a constant leak to earth that drained the battery.

kommando,
You wrote that you would not touch a Wassell replica.What are the choices if they are making them for Lucas if that is the case?
Thanks,Mike

 

[Fast Eddie]

Thank you Nigel,
I made a similar bracket and will give it a try.
Appreciate your picture.
Mike

Without teaching you the obvious, just take some time to ensure no wires are tight, trapped, chaffing, etc. There’s not a lot of spare space there. But there is enough, so long as you take some time and care.

 

[Triton Thrasher]

I just measured an original against new Lucas 2 & 3 phase stators, and the new Lucas ones have an inside diameter 0.010" smaller than the original.
I haven't checked a rotor yet.
@Fast Eddie reported seeing evidence of physical contact on his before having the rotor skimmed, so my plan is to ensure a running clearance of at least 0.025" on future builds.
I doubt if a greater clearance would materially impact performance, given the new ones are already over-rated for the job...

If Wassell’s pet manufacturer is making stators with too small internal diameter, how long can that go on for?

If they all fail in service, sellers will get them back from customers.

People will buy Shindengens and still have burnt-out alternators.

 

[concours]

If Wassell’s pet manufacturer is making stators with too small internal diameter, how long can that go on for?

If they all fail in service, sellers will get them back from customers.

People will buy Shindengens and still have burnt-out alternators.

The same thing was going on with the Sparx branded staters, they would go off like flash cubes.

The end user in many cases is not a technical person, and seeing how this is an electrickery part, including voodoo and black magic, accountability rarely is implemented.

 

[Fast Eddie]

If Wassell’s pet manufacturer is making stators with too small internal diameter, how long can that go on for?

If they all fail in service, sellers will get them back from customers.

People will buy Shindengens and still have burnt-out alternators.

Thats IF they are ALL TOO small.

A lot of variables are in play I suspect.

When does ‘smaller’ become ‘too’ small? Maybe they’re on the edge of ‘too’ small so don’t affect everyone?

Maybe they’re very variable, if some are correct, or even too big, no-one would know unless they measured it and compared it to an original!

I personally believe there are a few things in play and it’s when they ‘stack up’ that failure occurs.

Furthermore, one problem with this industry is the ‘batch’ nature of manufacturing. It’s quite conceivable that they may have made changes, but inventories around the world are still full of ‘old’ spec parts and the consumer has no idea or control over what they’re getting.

 

[kommando]

What are the choices if they are making them for Lucas if that is the case?
Thanks,Mike

A company called LAP formed by ex Lucas employees bought the original Alternator stator and rotor tooling. They first sold them under the Lucas brand as they were ex Lucas and Lucas had lost interest in Motorcycles. When Wassell rented the Lucas trademark LAP had to stop using Lucas and instead put a Union Jack on the box and Made in England. They continued to be sold by TMS.

TMS Nottingham

But that option now looks to be gone, they were undercut in price by Wassells so probably no longer make them but they were sized correctly and I bought some as spares.

LAP still do vehicle lighting based on old Lucas designs

LAP Electrical

Based in the UK, LAP Electrical is a well-established name in the, production and distribution of high-quality, Beacons, Lightbars, Strobes, Work Lights and other Automotive products.

www.beaconsandlightbars.co.uk

Wassells have been wrongly sized from the start and probably reluctant to fix the tooling.

 

[concours]

Thats IF they are ALL TOO small.

A lot of variables are in play I suspect.

When does ‘smaller’ become ‘too’ small? Maybe they’re on the edge of ‘too’ small so don’t affect everyone?

Maybe they’re very variable, if some are correct, or even too big, no-one would know unless they measured it and compared it to an original!

I personally believe there are a few things in play and it’s when they ‘stack up’ that failure occurs.

Furthermore, one problem with this industry is the ‘batch’ nature of manufacturing. It’s quite conceivable that they may have made changes, but inventories around the world are still full of ‘old’ spec parts and the consumer has no idea or control over what they’re getting.

Those thin sheet metal plates that are stacked up to become a stater once wrapped with wire are stamped from coiled sheet with purpose made die in punch set. As that die set wears, some re-grinding and sharpening may have occurred. All of which would not vary the dimension of those plates much at all. We're talking in a few tenths, half of thou perhaps.

 

[Andy Higham]

5 minutes ago postie delivered a brand new Lucas branded rotor from Fast Eddies motorcycles.
I gather the nominal diameter is 74mm, I have measured this rotor at 73.98mm.

Without knowing the correct dimensions and tolerances of parts, none of us can say "it is wrong"

 

[tompkins]

If they were too small wouldn’t they smoke up as soon as you start the bike? Mine ran fine for a few days and a hundred miles- that’s a lot of revolutions for too small- I just figured it had crap wiring internally that shorted out somehow. Incidentally, mine was during the break in period on a fresh restoration, so I was in the primary a few times adjusting the clutch and chain tension and never smelled burning or saw the stator getting melty. I’m no electrician tho, and this story is merely more anecdotal evidence to add to the heap…

 

[Andy Higham]

Another thing to add to to the mix.
As a bolt up construction, Norton cranks are more flexible than Triumph or BSA cranks (hence the so called superblend main bearings). This could lead to the end of the crank whipping at high rpm. Maybe Nortons require a little more rotor clearance

 

[SteveBorland]

View attachment 124228

Here's where I put may new Lucas box

View attachment 124228

I mounted my Lucas box just in front of the LH shock, on a small bracket, and led the cables through the gusset hole on the RH side

 

[johnm]

5 minutes ago postie delivered a brand new Lucas branded rotor from Fast Eddies motorcycles.
I gather the nominal diameter is 74mm, I have measured this rotor at 73.98mm.

Without knowing the correct dimensions and tolerances of parts, none of us can say "it is wrong"

But is it perfectly central to the shaft.

As I said above mine clocked uo on a lath showed it needed a 5 thou skim to centralise.