Muller Dynamo

[nul-points]

I have tested them separate, before having this messy diodes on top of the bridge recifier.

The test was done for a single coil pair, not all togheter.

ok, thanks for the info Romero

not all type of schottky diodes have a low forward voltage drop - and also, the voltage drop may be higher if the current flow is near to the max current rating - so is it possible that the particular diodes which you tried were not suitable for the current from the coil?

the 1N4001 only has a current rating of 1A, and a max voltage drop of approx 1V - do you happen to know off-hand what the rating of your bridge recitifiers are?

the SB1240 example i posted earlier has a forward voltage of 0.45V and a current handling of 12A, so a schottky like this should still give a low voltage drop at the current levels in your dynamo

thanks
np


http://docsfreelunch.blogspot.com

[neptune]

 A few thoughts on winding coils . Today I got 3 degaussing coils from the scrapyard . All three were wound with normal wire , not multistrand , so that idea is out . In Romereo`s  design , the core only protrudes a short distance beyond the bobbin . This is a shame because it is probably not quite long enough to grip the protrusion in a drill chuck  , which would make the winding quicker and easier . If you are using cut down ferrite rods , you could make it longer , but this might spoil the magnetic properties .I f you "roll your own" multistrand ,do not twist it too tight . indeed it will wind better if you do not twist it at all .If you can mount the coil in a hand cranked drill fixed in the vice just let the coil pick up the wire from the floor like a winch . If , instead of using a bobbin you glue the coil cheeks direct to the ferrite , make sure they are firm .Winding wire creates a lot of pressure , As in wire tension x number of turns .

[mikestocks2006]

I have lots of them, a big box full of S30D45CS ; SBL1640CT; STPS3045CW; STPR1620CT,SB3045ST; S20C10CC,....
I have tested those and performance was lower than existing ones 1n4001. Maybe they do work good but at higher frequency BUT not in my current setup.
Maybe someone can explain and help me decide what to use in the next setup.

@romerouk
This maybe of relevance ,
"The most evident limitations of Schottky diodes are the relatively low reverse voltage rating for silicon-metal Schottky diodes, 50 V and below, and a relatively high reverse leakage current. Diode designs have been improving over time. Voltage ratings now can reach 200 V. Reverse leakage current, because it increases with temperature, leads to a thermal instability issue. This often limits the useful reverse voltage to well below the actual rating."

While the forward voltage drop is typically lower about 50% less, for example S30D45CS vs 1N4001 , the reverse leakage current is much higher, 5miliAmps at 25C all the way up to 80 miliAmps at 100C vs 5 to 50 microAmps.
This can be a noticeable issue especially if the rectifiers are heating up.
I hope this helps
Mike

[hartiberlin]

Well, maybe it is better to put all outputs coils then in series
for higher voltage outputs and only have a normal
silicon diode bridge rectifier then at the end.
Then you could also use a DC to DC converter with high efficiency to transform
the violtage down again.
This way you will only loose power in the ONE bridge rectifier and not
in all rectifiers... This could also save a lot of wasted power in the circuit
and it is cheaper as you don´t need so many rectifiers....
If you make the coils much bigger also a higher current should be possible at
the higher series voltage.

Regards, Stefan.

[alan]

Should be superior to ferrite, for example you can make much more narrow gaps w/o saturating cores => more output. If it works at all
From where did you get the stuff?

I found this supplier:
http://www.alibaba.com/product-gs/443365023/power_amorphous_cores.html