S1ZB60-4072 Rectifier Bridge in series?

[fastesteddy13]

Hi..

Have built my latest wind generator prototye, have wound my own coils am planning on using a S1ZB60-4072 rectifier
https://www.ebay.co.uk/itm/S1ZB60-4...var=414496641536&_trksid=p2060353.m2749.l2649
on each coil and had planned to link them in series to increase the voltage.. Is this a sensible way to go?

 

[Harald Kapp]

The resukting output voltage will vary according to the pase shift between the single coils.
Put a large capacitor across each rectifier output to remedy this effect.

 

[fastesteddy13]

Hi Harald..
Bought a bunch of 25v 220uf caps to do exactly that..!
Like this?

 

[fastesteddy13]

Ah.. image did not stay on the post..

 

[Harald Kapp]

Yes, like this.
220 µF may be a bit on the small side. A rule of thumb for a smoothing capacitor is 1000 µF / 1 A.

 

[fastesteddy13]

Thanks Harald..
Am aware they are a bit small, this is a prototype and smaller scale version.. Vertical savonius type and everything is scaled down a bit, height is 40cm, diameter 28cm.. If this works, and I can charge phones, ipads etc with it, will then scale up to a much bigger one, 1.2mt in diameter..
I am more of an engineer than electrician, so this is all a bit of an adventure for me..

 

[Harald Kapp]

Kep us up to date with your progress...

 

[fastesteddy13]

Progress.. or lack of it I think.. Built it, it spins very well in a light breeze, has 19 coils (100 turns 0.2mm) with 30 magnets rotating at each end of the spindle.. Voltage coming out is all over the place.. Goes between 6mv and 5.8v when it is spinning at the same speed (used an electric drill). The moment I connect anything to it, even a multimeter, the voltage drops right down to nothing.. Cant even light up an led with it..
Perhaps I should have stuck with engineering..

 

[Harald Kapp]

100 turns 0.2mm

Try 1000 turns or more.
100 turns doesn't make a great inductance, but voltage generated relies on the inductance. According to Faraday, voltage generated is equal to the number of turns times the change in flux:
v = N × dΦ/dt
with N being the number of turns. Therefore more turns -> higher voltage.
You may also want to use iron cores to concentrate the flux within the coils, thus further increasing the output power.

 

[fastesteddy13]

Hi Harald..
Ah, been barking up the wrong tree.. Had concluded that I should not have connected the caps in series, a search around the net had me digging out a calculater to try to work out how many farads I had to work with when 19 caps @220uf were linked in series, not a lot was left.. Thought this might have been why it could hold so little charge..

 

[ratstar]

Perhaps I should have stuck with engineering..

This isnt engineering? what is it then?

 

[fastesteddy13]

Toolmaking is very different to electronics.. I trained in one, avoided the other.. Which is why I am now flailing around like a caveman that has been given an iphone..

 

[ratstar]

haha. Just wait till you get it too efficient and then youll have to hide it from people to avoid being shunned.

 

[fastesteddy13]

We are in full lockdown here (north Scotland), dont think I would notice being shunned right now..!

 

[fastesteddy13]

Before I get out my biggest hammer, can anyone confirm my thinking on these capacitors? I have wired the stator according to a youtube vid I watched, but I am more uncertain about this now.. Coil ->bridge rectifier -> capacitor, then linked the caps in series to a pair of outputs. Am now thinking that the bridge rectifier should isolate each coil nicely, then link the rectifiers outputs in parallel and wire them into a larger capacitor, then output..

 

[Harald Kapp]

Parallel connection is not a good idea. The rectifiers will block power transfer from the coils with lower output voltage and will let pass only power from the coil(s) with the highest voltage. Thus you will lose the energy from the low-voltage coils.

To verify your setup is working at least near your expectations, measure the output voltage of the individual coils with your multimeter in AC range before the rectifier. Disconnect the rectifiers if required to reduce the load on the coils to 0.
As I stated, 100 turns are not enough to provide a usable amount of power. Look at a commercial dynamo or alternator for reference. You will find many more turns of wire plus an iron core.
You may be better of concentrating on the (aero-) mechanical aspects of your wind generator and simply attach the drive shaft to a commercial dynamo.

 

[fastesteddy13]

Thanks Harold.. I will certainly re-check the coils in a/c, did not do that before.. Am determined to make my own coils to do this, objective is to learn, not create a super efficient turbine.. Just means I am going to hit a lot more speed bumps as I go along..!

 

[ratstar]

Hi Harald..
Ah, been barking up the wrong tree.. Had concluded that I should not have connected the caps in series, a search around the net had me digging out a calculater to try to work out how many farads I had to work with when 19 caps @220uf were linked in series, not a lot was left.. Thought this might have been why it could hold so little charge..

Theres nothing wrong with having caps in series in this situation, if you have them in series they will be a high voltage output but the charge is the same as if it were parallel (the power output watts is the same), if you grab both ends.

Probably looks easier if you have them in series.

If you spin your "whirly gig??" enough, you should develop charge in the caps, then you might get a spark when you put both ends together, but! watch out for electric shocks, for caps in series!!!!

 

[fastesteddy13]

Thank you Harald..!!! I wound just one coil, not sure of the number of turns, just wound it as big as I could without remaking the whole thing.. Got up to 1.6v dc from it and it averaged 1.25v..! No iron core, just open (axial?).. This little 'whirly gig' can take 38 coils (19 top/bottom) which gives me loads of charge to play with, might even be able to shock myself properly..!

 

[Harald Kapp]

Nice build. May need some weatherproofing, though .

Got up to 1.6v dc from it and it averaged 1.25v

Here's where you'll run into an issue with your setup: A common bridge rectifier drops around 1.2 V. That is why you are left with no usable output voltage after rectifying. You can reduce the voltage drop by building the rectifier from Schottky diodes (i haven't seen complete bridge rectifiers from Schottky diodes as comparable parts). That will reduce the voltage drop from ~ 1.2 V to ~0.6 V - 0.8 V.
Easier to wind some more wire onto your coils plus add the iron core (sorry, I repeat myself). You can increase the magnetic flus and thus the induced voltage even more by closing the magnetic loop as much as possible. I'll try to sketch what I mean:

This is (supposed to be ) a schematic side view of your construction. All I added is the blue yoke, made from soft steel so its easily magnetized. The yoke is meant to be fixed to the upper arm (lever), reaching through the coil from the top and under the magnet(s) from the bottom. Ideally there's be a groove in the underside of the carrier disk and the yoke would extend into the groove to minimize the gap between magnet and yoke. This yoke will concentrate the magnetic flux considerably. The overall construction of your "turbine" doesn't have to be changed much.