Hi
Any ideas why my dynamo armature throws solder off from wire ends. I had to resolder them few times, when charging is coming too weak. Something to do with combined too much heat and centrifugal force.
Thanks
Kalle
Hmmm - heat and 'G' or possibly solder grade ?
I would suspect excess heat as being the problem - caused by too much current.
Question is why the excess current?
Do you have any other electrical problems - like boiled battery, blowing lights, battery going flat quickly, etc?
Rare to have one electrical problem in isolation ...
Things that can overload a Dynamo -
...... 6-12V conversion?
.......third-party field/armature windings ?
.......An internal short in the armature - caused by insulation failure (caused
.......Regulator
Have a good look at the commutator while you are at it - is it all an even color or are there any low spots (not polished) or burn marks.
Are the insulation slots between the commutator bars clear and not smeared over?
There will be somewhere on this forum or the excellent matchless dynamo thread (don't have the details at the moment) - the method of measuring resistance for each armature winding - I think it is by measuring resistance between adjacent 'bars' on the commutator ?
I have used standard 40:60 solder for this kind of job, without problems, though many (many, many) years ago used to rewind slot-cars and this was a common problem, solved by using a different solder.
Some Lucas armatures have a slotted tab to which the armature wires attach - the idea being that you can lightly crimp the copper wire, in the slot, before soldering - hence giving better load carrying (against 'G').
If can convince yourself there are no other problems - try a different solder grade then wrap cotton thread around the all the wires to the commutator and then smear epoxy over the lot - basically 'potting' the commutator wires.
email (option): ginantonik@tiscali.co.uk
Hi, thanks for response.
Armature is original 6V
resistance is more or less 1ohm all windings
I don't remember any special colour or burn marks on commutator
No problems with blowing lamps or boiling battery. I use dry battery 5Ah btw.
Ammeter does not show too much current.
Only problem I had was dynamo end bush rotating in housing last year. Maybe this caused the heat? Solved it by clueing new bush.
Now commutator is cleaned and wires soldered again, works ok. Still need at least 25-30mph on top gear (lights on) to move needle to the positive side. Is it normal?
Kalle
Hi Kalle
Just a long shot. Heat = Current x Current X Resistance. You need to find a high Resistance, which will be the source of the heat. One brush is earthed. Do you have a good earth connection. If not, the resistance will cause heat that could transmit to the commutator via the brush.
Regards
Peter
email (option): pvlietstra@gmail.com
Hi Kalle,
This problem usually appear when the dynamo has to charge non-stop,
So it has no chance of cooling down.
It can happen when using a car battery, which you don’t,
Or with a regulator which is trying to charge in a higher voltage than needed, (Above 7.2V)
So the generator works non-stop to try and get the battery to a higher voltage than it can,
Resulting with a non-stop charging.
Another case I have seen, is when using a high wattage of bulbs-
Like a car's 40W or 60W at headlight, with the rear 5 or 10W and so on,
Which basically draws more Wattage, and therefore current than the generator can produce,
Making it work overtime.
Anyway, I would check the regulator first.
Noam.
'Brush rotating in housing' ?
The brush position does determine charge rate (used in earlier forms of regulation) - but I'm not certain how yours could have rotated ?
If the pair of brushes rotated as a pair - then they will have stayed in same position as each other (180deg) - so no problem.
If just one moved (not sure how?) I presume you glued it back into same position ?
Yes it does sound as if you have a high (current) load on the dynamo - first thing I'd look at would be the regulator - BUT I would have expected other signs of problem. as well.
One problem of 'dry' SLA batteries is that they don't 'boil' - the first you know of problems is when they have started to bulge and no longer fit the battery box !!!
Followed quickly by lack of storage (flat overnight) and higher than expected continuous charge rates..........
Followed by the top blowing off (on my sit-on lawnmower!!)
Most SLA's used on old bikes are for alarm systems and such, and don't like charge rates of more than a few amps, more highly rated rated high charge/discharge 6volt ones are rare and relatively expensive.
And before everyone says they have no problem - yes they are used successfully by many, usually due to the p***-poor output from our dynamos.
I have used them myself.
Always a good idea reducing battery load by fitting LEDs and QH bulbs where possible.
email (option): ginantonik@tiscali.co.uk
If you have a multi-meter and know how to use it - try measuring the voltage at the battery and rev the bike up/down, with lights on/off.
The normal charge 'profile' would show a voltage change across the battery terminals something like ;
6-6.5 volt - no engine
7-7.5V - when engine first started and running at a fast tick-over -
falling to say - 6.5-7V as the battery reaches full charge (if a mechanical regulator take lid off and watch the solenoids click in/out)
At same rpm - switch on lights and watch the voltage - it should drop, then jump back up to the initial charge voltage as the regulator 'asks' for more current from the dynamo.
Let us know what numbers you get.
If you are 'short' on volts, the current will rise to compensate (watts = amps x volts) hence loading/heating up the dynamo.
The best way is a DC clamp-on ammeter so you can measure current from the Dynamo to the battery - if you know an auto-electrician of someone ?
(a regular AC clamp-un won't work)
as I write this, I wonder if you have a cell 'out' on your battery, so you are not getting anything like 6volts?
this would cause the current to soar as it tried to compensate?
a voltage check would tell you
email (option): ginantonik@tiscali.co.uk
Hello, thanks.
For the first it was bronze bush rotating in end casting not brush. Sorry for bad description. I have good multimeter and know how to use it too. I will test it when I have time for this. So far it will be like it is. I will try to use pilot light only on smaller roads.
Kalle
Kalle - let the forum know what you find.
As for bad descriptions - there are plenty of 'things', 'do dabs', 'wjucums' in engineering + many things which have correct names which no one understands.
As for some official (as in parts manual) part-names, which have little to do with what they are or looks like!
Currently been chasing a part for my lawn-mower - something I would call and have been looking for - a bearing housing - but no, our cousins over the water call it a 'blade-mandrel' ???
What's in a name!
email (option): ginantonik@tiscali.co.uk