Dynamo

[PeteH]

Old trick for getting bushes out of blind holes As tight a fit steel dowel and fill the hole with grease insert dowel bash with hammer normally the bush will be driven  out by the grease you can try putting it in a vice which is slightly less brutal.

Pete

[Wagger]

1 hour ago, Chris A said:

 

Don't blame me I was just quoting johny. I don't know the difference between a tap or a valve. Robinet ou vanne

Lol too.  I once confused tapping with planishing on a school exam paper. Taps and dies. (Thread cutting) Fawcets and valves. (plumbing). Valves and tubes. (early radio electronics). Indeed, we have a confusing language.

Maybe we need a thread cutting device for thread drift.

[PeteH]

Yea but life would be much less interesting 🤔 

[Chris A]

4 hours ago, Wagger said:

It sounds like the armature segments are shorting

Is there any way I can test them?

[Wagger]

There is a way of testing but you need a device that can measure very low resistance. You then measure the resistance between opposite segments of the commutator, working round one pair at a time and noting for comparison. Having spares to compare with is also handy. I could strip mine down if I become really bored.

The field windings have a higher resistance, and do produce a magnetic field that you can detect with a steel rule or screwdriver.

You may be able to find the figures from winding specialists, or the manuals if any of them detail these.

[Chris A]

Wagger : Thanks for the explanation, but I think I'll give it a miss and have another drink instead.

[Wagger]

Good on Ya. One can end up going round in circles. It is not fot the faint hearted.

 

[Chris A]

Maybe I should just right it off and regard it as a possible source of spares . . . BUT I don't like not being able to get something sorted.

I'm going to think it through for a day or two before deciding whether to order a bush or not, the drop dead date will be when the item I do want becomes available with the same supplier and I place my order for it and some other stuff.

I thought of changing the title to dynamo but can't seem to get the option . . .

[Pete Lewis]

should be able to edit the title but need to go back to page one  1st post and  click the  edit  (3 dots) 

then re write the title 

Pete

[Wagger]

There are some good videos online showing how to check an armature commutator. Do it after separating the segments.

Basically, it is:-

Measure the resistance between all opposite segments. Note them for comparison.

Measure the resistance of adjacent segments. Note them for comparison.

Measure the resistance between each segment and the iron part of the armature. There should be no continuity at all there, that would indicate insulation breakdown.

Any large fluctuation in readings indicates shorted or open circuit turns. Shorted turns drastically reduce performance as a generator.

You can get  these rewound at great expense, but not worth rebuilding it if the armature is faulty.

Hope that helps.

Lloyd.

[Chris A]

Wagger, thanks for that - as it is raining today so all planned outside activities cancelled I might have a look at some videos as you mention.

[Chris A]

1 hour ago, Pete Lewis said:

should be able to edit the title but need to go back to page one  1st post and  click the  edit  (3 dots) 

then re write the title 

Pete

Yes! Even I can still learn, now i need to let my brain cool down  . .

[Pete Lewis]

but you've  done it    

we all find out by looking over someones shoulder   

there is no easy way , like computors, very few of us old uns have any training in 'how did you do that'

Pete

[Chris A]

57 minutes ago, Pete Lewis said:

there is no easy way , like computors,

I just hit the buttons then see what happens next. I particularly favour any big red ones as they always seem to do something.

Like many years ago when I worked, here in France, in a sawmill and we moved to a new site and new machines. It was clearly explained to us that at the end of the day we shut individual machines off with their small black button. The big red one was the 'panic' button which shut down ALL machines, including the main one that should NEVER be switched off while cutting. Well, at the end of the first day I pressed . . .You guessed it! The guy on the main machine was livid as it risked ruining the blade. . . .

[Pete Lewis]

as with french there seems less vocabulary to explain things i guess there was alot of gesturing going on 

i found in the factory at St Priest ( Lyon)   much arm waving and shouting was fairly normal comunications

i came to the conclusion neither guy had any clues about what they were arguing  about

but we all had a good party when i had to return to UK they shut the dept for the afternoon  

Pete

[Chris A]

There is a whole second language to learn, the different gestures to accompany a phrase can totally change the meaning.

I'll try and explain.

Ask a workman when he is going to start the job.

He says next week. No hand movement then, yes next week.

Puts his hand out with back of hand upwards and rocks it from side to side while he replies means, next 10 days to 2 weeks.

Does that with both hands and you won't see him for a month.

Should he resort to shoulder shrugging - well that's many months off. .

Guess how I learned the language.

There is also the subtile difference in definition of words. Here in Normandy we are bit relaxed. After a while here I asked my boss what he understood by 'toute suite', a delay of 15 to 20 minutes for him.

Even more locally we have the 'quarte d'heure Percheron' nothing to do with horses just the local area. Take the case of something due to start at 8pm, the 1/4 d'heure should mean 8.15 but no 8.30.

Some years ago a local wanted to do a concert of sound effects, as per on radio, in the church. He wanted it to start at 8pm so the publicity went out saying 7.30.

I can cope with all that except for my 4pm cup of tea which has to be at 4pm!

[Chris A]

Just got time before making my cup of tea (see above).

Tested the armature as per a nice easy to understand video and my simple multi meter. No faults found anywhere.

I'm going to put it down to the fact that the bush wearing out, after 8800 miles, allowed the rotor to move and touch the side plates, the wear marks and contamination on the rotor seem to back this up. Was the bush poor quality? Fan belt too tight putting strain on it? Don't know, won't worry about it (too much) either.

The rotor spins nicely, no movement in the bearing etc.

I will (eventually) lash out the 14€40 for a replacement bush when I place my order and rebuild the dynamo.

The 'revised' availability for the main item I want has now slipped to the beginning of July, it started off as being the end of May. My order list has doubled during this time!

Wow, perfect timing, off the make my tea!

[Pete Lewis]

my french was never very good   that explains why    maybe i should have just kept hands in pockets then 

Pete

[Wagger]

Too tight a belt will bias the wear on the rear bush. I have kown guys reversing the end plate just to get wear on the other side, but that risks the dynamo coming loose as the rear is not supported properly.

In my motorcycles that originally had bronze layshaft bushes, Triumph and BSA replaced them with needle roller bearings in a cap.

If you measure the shaft , you may be able to obtain a bearing that will fit it. Then you need to bore the hole out carefully so that it will be a light inteference fit for the cap. A good grease should stay put in it, or drill a hole and use the felt washer set up as before.

It's a bit of an over-kill, but it seems that you like messing about, like I do.

I did my apprenticeship at a switchgear company, so was taught all about motors and generators. Just ask if you need more info.

[johny]

Ive just had to replace the front roller bearing on my C42 which is original and done 80k miles. The back bush is fine and I wonder if its more usual for the roller bearing to wear out due to no facility to grease it, the belt side load and also greater exposure to the elements...

[Chris A]

1 hour ago, Wagger said:

Too tight a belt will bias the wear on the rear bush

That's what I was beginning to think could be the cause of the wear. Interestingly enough just about the only spares that are easily available are the carbon brushes and the bush, which must say something.

There is no way I'm going to be replacing the bush with a bearing. If it works with a new bush great if not it's for spares.

I am going to ensure the fan belt is just tight enough to grip and no more. I had thought the tension was as per book but maybe not.

[Chris A]

5 hours ago, Pete Lewis said:

my french was never very good   that explains why    maybe i should have just kept hands in pockets then 

Pete

After having been over here for a few years l went back for a visit and met up with some old friends over a meal. One of them actually commented that I had become French because of all the arm waving I now did.

[johny]

yes the load on the belt is pretty low as the electrical system and water pump dont demand a lot of power but of course if driving in heavy rain there could be more chance of slipping...

[Chris A]

5 minutes ago, johny said:

course if driving in heavy rain there could be more chance of slipping...

No problem here then 😃

[PeteH]

The "science" of V/Wedge belting is that the belt drives on the sides of the vee. What often happens is the Owner/Mechanic, is not conversant with this principle, and when the belt wears just keeps tightening the belt, which eventually is now trying to drive on the bottom of the vee, and slipping, so said operator tightens and tightens belt, by this time the force on the bearings is causing the sort of wear Chris is observing. The next owner more conversant replaces belt, tensions to spec; and only discovers the past transgressions when the device fails. Even in the wet the belt should drive if it is correctly tensioned and driving on the sides of the vee.

As an aprentice, I, along with several others, was taken by our training officer to the nearby Fenner Factory, and given the "tour" and a long disertation by their training officer!. something must have stuck, despite the distraction of several hundred female operatives who comprised the bulk of the workforce!.

Pete