How not to B33!

[Dan_B33]

Is been workin on the bike.
6v bulb alight connected as you described.
Multimeter reading was right as well. Suddenly it stopped working.
Dynamo spins anti-clockwise. (Points spin clockwise).

Might be the case for rewinding

[Rog1]

Dynamo spins anti-clockwise. (Points spin clockwise).

Might be the case for rewinding

Of course it does; my mistake!

Regarding the bulb and multimeter, do you mean you did the tests I described?

[Dan_B33]

Hello Róg,
Yes when it worked I did that test.
I know it is not working since I have tried to repeat it.
With multimeter test when I swapped the cables and connect plus to F and reading gave" -" before number.

Now I get no reading and no light in the bulb.

Other questions about refub. Dynos: P.DUNN DYNAMOS
Any good experience with that?

[Dan_B33]

Hello,
Current status with Dynamo.
I have stripped it couple of times to double check and triple check.
Measured all armature looks intact.
Flashed it with 12V battery to positive earth.
Now it gives some output....up to 7V on highest (drill) rpm. Not satisfied with that since on lower rpm it is fat bellow 6V.

Looking for some dynamos on eBay.
Question is if I buy clockwise Dynamo can it produce current running counterclocwise? Shall I jus swap field coil terminals?

[Rog1]

Don't forget that when it's installed the dynamo runs at higher rpm than the magneto; looking at parts diagrams and number of gear teeth it runs at 58 teeth/22 teeth or 2.64 times magneto speed. The magneto runs at half engine speed so the dynamo is running at 1.32 times engine speed.

Now divide the fastest speed your drill runs at by 1.32; what do you get? That's the equivalent engine speed. Of course dynamos are all pretty poor at low speeds, too.

[iansoady]

I agree with Rog1 - I spent ages trying to track down a "fault" on a dynamo just because the drill didn't turn it fast enough and I was getting the same low voltage. Once installed it was fine.

[Dan_B33]

Thanks for all replies.
I have run it as a motor for 2 minutes with same 12V battery I used for flashing.
Now at highest rpm produces up to 9.2V
Shall be fine with DVR2P...

[Rog1]

Thanks for all replies.
I have run it as a motor for 2 minutes with same 12V battery I used for flashing.
Now at highest rpm produces up to 9.2V
Shall be fine with DVR2P...

Excellent news.

[Steve.S]

Dan,
I think you might find that with the wires joined together, and a normal electric drill running at 3000 rpm, it should be producing a good deal more than 9.2 volts. We shall see.
I have had good experience with Dynamo Dunn BSc (Hons).
The Rucas rubber battery cases are rather nasty, and collapse when the strap is tightened.

[iansoady]

I don't think the average cordless drill will get anywhere near 3000 rpm- 1200 or so is more likely.

If you do decide you need it to be looked at then Paul Cooper sorted one out for me but I'm not sure if he's still working.

[Steve.S]

Well, I have 2 Black & Decker corded drills, both of which show a maximum no load speed of 3000rpm. So it would seem that a cordless drill is not suitable for testing dynamo output.
In my experience, using these corded drills, the dynamo output is way above 9V, and will easily blow a 40W bulb, although the load will bring the rpm down considerably.
Just my experience. Perhaps Dan is using a cordless drill?

[Dan_B33]

Well, I have 2 Black & Decker corded drills, both of which show a maximum no load speed of 3000rpm. So it would seem that a cordless drill is not suitable for testing dynamo output.
In my experience, using these corded drills, the dynamo output is way above 9V, and will easily blow a 40W bulb, although the load will bring the rpm down considerably.
Just my experience. Perhaps Dan is using a cordless drill?

Hello,
Yes I'm using cordless 20V drill.
Terminal F and D were coonected and this was showing at highest rpm 9.2V.

[Dan_B33]

I have checked drill specification.
Max RPM is 2000 so this top 9.2Vs were created at around that speed.
I have changed bearings and brushes+ cleaned commutator a bit (space between sections with "saw" and surface with steel wool).

For now it shall do.

Now waiting for other bits to be shipped to my brother. Then all comes to me and I could move forward.

Waiting for that I will start building electric ⚡ circuits.

[Dan_B33]

Hello,
Package from UK arrived!
@Neil thanks for parts !
I can start finalize front forks

[Dan_B33]

Front spindle

I have to rework this front spindle.
Shall I go and adjust for the bush? Like orginal?

Shall I make it without bush? That shall still fit front slider.