Shorting coil gives back more power

[conradelektro]

@Joe:

I post a circuit which uses optical gap sensors to switch ON and OFF at an adjustable angle very precisely. It was not intended for coil shorting but can be adapted easily. One needs as many "fingers" as magnets, but only one pair of optical sensors (defining the angle). The optical sensors are triggered by the leading edge of the "fingers".

The "fingers" switching the two optical sensors could be on the circumference of the wheel with the magnets (not necessarily on a separate wheel).

The optical sensors worked much better than any hall sensor or reed switch solution I tried. Although, the optical sensors need about 5 mA to drive the LEDs (shining in the gaps).

Greetings, Conrad

[Tudi]

Guys. Pls, 1 simple question : What is input P and what is output P ?
As I understand that P=U*I, here you guys get nice U(volts) as output but probably with the cost of I.
Can anyone post a conversion factor for this whole ghizmo ? It's really nice to see a lot of enthusiasts, but if you drive to achieve a 100% conversion ratio you would need to eliminate everything. It makes logical that the more things you add they will convert more power ( P ) = you will get a lower conversion ratio. So before we start adding more and more components to simply get nicer visuals on an osciloscope let's try to focus on the basics ? As i see this is a simple resonant circuit that stores input energy in the coil and capacitor and from time to time it dumps to a batery. This is all nice and logical, not sure why people think there is any gain in this. It's just a I to U convertor circuit.
ps: i know i'm a day 1 sceptic

[joefr]

Hi Conrad

You have nice setup

Thanks for circuit schematic and picture of your setup.

Joe

[joefr]

Hi Gyula

Can you please help me choose which optical switch to use:
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&N=4294571106+4294909763&Ns=Maximum%20Rise%20Time&Nso=0#resultArrow
I was thinking the first model in the row ( Slotted IR optical switch,OPB460T11 )
Here is the datashet: http://docs-europe.electrocomponents.com/webdocs/025c/0900766b8025c2fe.pdf

And can you please change this schematic to use optical switch instead of the hall sensor:

Joe

[gyulasun]

Hi Joe,

Ok,  tomorrow I will upload the modified schematic with the opto added.

The type OPB460-T11 seems already a good choice (it has an output rise and fall time of 50ns, maybe an overkill in this application for the present some hundred RPM, if you choose this type it will never ever be a limiting factor in speed, that is sure).
If you read the data sheet of the TCST2103,
http://docs-europe.electrocomponents.com/webdocs/0e30/0900766b80e30a58.pdf
its turn on and turn off times are specified as 10us and 8us, respectively. This is about a thousand times slower than the above one but I believe it still good for here. Conrad surely found it good for his practical setups.
So if you choose the OPB type I will make the schematic with it tomorrow.

Gyula