Yet more E3N dynamo questions

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Group Leader
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Yet more E3N dynamo questions

Post by Group Leader »

My '53 16MS dynamo had no output and on investigation I found two pairs of commutator segments were open circuit.

In the spirit of "Nothing ventured, nothing gained" I thought I would try re-flowing the solder connections between the wires and the segments (assuming they were soldered originally) and I successfully managed to restore the correct continuity. However one of the wires was actually broken at the joint and although I managed to bridge the gap (to prove the point) I considered it not to be an adequate solution. So another trip to see that nice chap called Steve, who is based nearby, and who has a very large cupboard full of AMC Spares (his location is just too convienent for my credit card to be safe!) and I have a replacement armature and bearings amongst other things. The old bearings on the old armature and the new bearings on the new armature are both an extremely tight fit.

So, to my question; How to fit the new bearings to the new armature?

My plan is to use a suitable size socket to bear on the inner journal of the bearing and then press it into place on the shaft using my bench drill (as I haven't got a proper press!), aligning things vertcally as best as I can by eye as I go. Does that sound OK? Anything to be wary of when doing it (apart from being grossly out of alignment)?

TIA.

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
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Rob Harknett
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Re: Yet more E3N dynamo questions

Post by Rob Harknett »

I have only ever simply pressed bearings in by hand. Maybe I have been lucky.
http://archives.jampot.dk/technical/Ele ... ynamos.pdf
Not sure if that gives any tips.
mick h
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Re: Yet more E3N dynamo questions

Post by mick h »

Place the new bearings in the freezer for 20 minutes, then try to fit. you may be pleasantly surprised. regards mick.
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Re: Yet more E3N dynamo questions

Post by aobp11 »

The question is about the fit of inner race on the shaft, so surprised yes, but pleasantly?
Albert
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Re: Yet more E3N dynamo questions

Post by Mick D »

Hi

A pillar drill is a good option if you don't have a press, put the armature into a sealable freezer bag and into the freezer for an hour or so before you start the operation.
Have the bearing at room temperature or slightly higher, but not too high to affect the lubrication or seals if fitted - lubricate the inner surface of the inner race, (as it's a tight fit - if it's an easy fit you would use 'bearing adhesive').
Install the bearing as you propose and as quickly as possible to maintain the temperature differential.

It will be fine :)

Regards Mick
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Re: Yet more E3N dynamo questions

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Thanks for the advice chaps, I'll give it a go and report back.

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
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Re: Yet more E3N dynamo questions

Post by Group Leader »

Well the deep frozen armature didn't seem to make too much difference (but I fully appreciate the principle behind the sugestion in this case so many thanks for the input).

So, a combination of "constant" and "impact" loads eventually got the driver side bearing in position (lucky I remembered to put the end casting on first!) but it took a lot and, I have to say, I wasn't over keen on the degree of "persuasion" that was required. I'd classify the fit as somewhere between BT and FT, if you know what I mean ;) As a consequence, the commutator end suffered slightly and required a bit of dressing to remove the resulting imperfections.

Anyway, it's all back together now and the shaft spins freely and after flashing it it seems to motor OK :)

Next job is to get it back on the bike, lined up, chains on and I can see whether it generates any juice.

Fingers crossed!

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
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Re: Yet more E3N dynamo questions

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Group Leader wrote: Next job is to get it back on the bike, lined up, chains on and I can see whether it generates any juice.
....... which it doesn't even after flashing the field coil again (Resistance is about 3 ohms which I believe is about right) :(

I've not had the field coil and pole piece out and I know that the pole piece has got to be in perfect contact with the housing. Might it be that some corrosion has built up between the two mating faces over the years preventing the residual magnetic field being adquate to start generating power? Purely as a test; could I temporarily power the field winding with the battery and check to see if it then starts to generate power with a properly energised field? If it didn't what might be the problem be, a shorted turn in the field maybe?

Anyway, to add insulte to injury, at least I now know I also need a new primary chain and, because all that slack had to be taken up somewhere, I will also need a new final drive chain (as the one that was on it seems like it might have been shortened to suit) :headbang:

Any suggestions would be most welcome!

TIA

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
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Re: Yet more E3N dynamo questions

Post by Groily »

One way to ensure that the polarity is correct, the rotation is correct, and to improve residual magnetism too, would be to motor it, if it will.

If you just do the usual link from F to D on the dynamo, then apply your chosen battery live to that wire and battery earth to the body, it should turn. One way or t'other. If it turns in the wrong sense, swap field coil wires round between F terminal and earth or swap the brushes round - but not both. (EDIT for avoidance of doubt - it should motor in the same direction as it would be driven on the machine.)

If it doesn't turn immediately, give the armature a flick to see if it will start it up, give the brushes a gentle squeeze, apply a squirt of contact cleaner to the commutator, etc.
Once it has motored, the body ought to retain a small dose of remanent magnetism, sufficient to get it to kick in as a generator when spun - quite fast. Battery powered drills often won't do it - you'll probably need well over 1000 rpm to get it going.
(Motoring doesn't prove all is perfect - but with a new armature it should be a good test as there won't be any dud windings on the armature to have to worry about.)

Once it has fired up, it should/may kick in subsequently at somewhat lower rpm and if you apply a load - maybe a 21W 12v car brake light bulb - between the link wire and the body when it is running, it should light it. (12v is easier as the filaments are easier to fire up without a battery in circuit than 6v ones and won't blow with revs so easily.)

Unlikely that the pole shoe to dynamo body connection is causing a problem, and 3 ohms field resistance is about right.

This link may be helpful: http://classicrider.dk/dokuments/Lucas/ ... E3N[2].pdf
Last edited by Groily on Thu Jun 15, 2017 6:43 am, edited 1 time in total.
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Re: Yet more E3N dynamo questions

Post by Group Leader »

Groily wrote:One way to ensure that the polarity is correct, the rotation is correct, and to improve residual magnetism too, would be to motor it, if it will.
Yes it motored OK on the bench after assembly but before putting it back on the bike although I have to admit I forgot to check the direction of rotation!
Groily wrote: Once it has motored, the body ought to retain a small dose of remanent magnetism, sufficient to get it to kick in as a generator when spun - quite fast. Battery powered drills often won't do it - you'll probably need well over 1000 rpm to get it going
- I used an AJS 350 engine to spin it ..... :)

Groily wrote:Once it has fired up, it should/may kick in subsequently at somewhat lower rpm and if you apply a load - maybe a 21W 12v car brake light bulb - between the link wire and the body when it is running, it should light it. (12v is easier as the filaments are easier to fire up without a battery in circuit than 6v ones and won't blow with revs so easily.)
That's what I was using for my test rig.
Groily wrote:This link may be helpful: http://classicrider.dk/dokuments/Lucas/ ... E3N[2].pdf
That's one thing about these machines; there's a fantastic array of information, period and contemporary, available on the old t'internet.

Many thanks for your thoughts, I'm pleased to say they confirm pretty much what I've done so far so I'm still puzzled!

Next things to try will be:

1) To power the field coil from the battery, load on the dynamo output, isolated from the field, and run the engine and see whether that will kick it into life (because it requires minimum effort)

2) Take it off the bike and confirm it still motors and confirm the direction of rotation is correct

3) By a new field coil (everything else excluding the brush holder assembly and the body is new)

4) Chuck it away and take up stamp collecting ...... not really :D Owning such a machine after all this time is a dream come true, I'm just keen and eager to have a go on it so stubborn problems like this are frustrating (and worn-out chains etc are a tad irritating on bike I understood just needed "routine annual maintenance") Mind you, if you have to replace the dynamo and chains every year I suppose it is routine annual maintenence!
Anyway, many thanks for the help so far.

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
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