The Ossie motor

[Jimboot]

what an intersting thread here  full of variable


theres is now 2 congigurations of the coils polarity

1-

the serial one that is for a 4 coils device   - + - + - + - +    which is the original Ossie's device and in this case , if you shortcut the coils you get a very strong BEMF and strong braking of the rotor, I say it is impossible to free wheel the rotor by hand.  And so far i understand,  in this config you have to tune the reed to insert the pulse motorising energy INSIDE the generaitve AC curve.

  And in this case we have to know if the AVERAGE generative energy can overcome the  TOTAL input energy ??



with this config,  on my really crude testing , i  am not able to get more than an average 15 % of generative back energy  have you better results ??


2-

is from Jimbot 's  contra serial config with - + + - - + + -  where the coils are facing eachother. In this config the rotor can be almost free wheeling with shorted coils.  And the extra energy comes only from the kickback spikes  In this config the BEMF  is almost zero  and on the scope a small trace is there but nothing to do with the generative trace.  But the kickback trace are very impressive.

And in this case we have to test if the very strong but very short Spikes (up to more than 200 volts) CAN BE TRANSFORMED in energy to overcome the input energy.

Yep !!!

good night

Laurent

Geez I really do have to learn how to use my scope properly! Very interesting Laurent, thanks.

[woopy]

@ Gyula

here some result of my latest config

i am now trying  new coils with o.3 mm copper   and 9.8 mh and 14 ohm,  and the config is JB config   - + + - - + + -
and so far i understand your questions   i made this test

- I disconnected the plus and minus of the bridge from the circuit

and i put the scope probe  on the plus and minus

basic data 

one 22 micro F 400 volt  across  + and - of the bridge rectifier

Main battery 4.5 volts nominal alcaline  at now 4.36 volts


1- without cap    that is direct on scope  the spikes can reach 230 volts

2- connect the cap  and it charges very rapidly to up to 60  volts and than slowly  up to 100


3 -i made the different testing  as you suggested      i put resistors acros the cap

and the results

  0    ohms (direct)            resistor     = the cap charges to 100 volts

  10 k ohms   resistor       = the cap charges to 3,5 volts (almost immediatel)y


  20 k ohms  resistor        = the cap charges to 5.95 volts

  47 k ohms  resistor        = the cap charges to about 10 volts

please let me know what the math says.. ??  is it interesting ??

good night

Laurent

[gyulasun]

@Laurent

Re on fast diodes,  the best is to look for ultra fast rectifier diodes that has a reverse recovery time of less than 25-35 nanosecond. There are diodes that has 4 nanosec t_rr like 1N914 or 1N4148 but their forward current and reverse voltage limits are too low here (100mA and 80-100V). And the higher current higher voltage diodes with less than 10ns t_rr are hard to find and expensive.
Here are some links leading to some diode types that you can see where to buy from in you country:
http://www.futurlec.com/DiodesPower.shtml  and see the MUR series in the middle and the High Speed series at the bottom like type RHRP860 with less than 30ns with 8A forward current and 800V reverse voltage.

ST Microelectronics also makes very fast diodes, try to find seller for their types that you may find here: http://us.st.com/stonline/products/families/diodes/ultrafast/ultrafast_rectifiers.htm

Fairchild Semiconductor is also an excellent diode maker, see here
http://www.fairchildsemi.com/sitesearch/fsc.jsp?command=eq&attr1=AAAFamily&attr2=Rectifier   and again the problem usually is where can you find distributor for them.  Maybe the big component sellers like Digikey, Mouser, RS Components, Farnell etc have most of these diodes.
The link above to Futurlec is also a possibility.

No need to hurry and order some exotic type though, only in case it would be justified. If you could have several 1N4148 or 1N914 types to select from, you may consider connecting them in parallel to increase forward current and in series to increase reverse voltage, or even in both combinations because they are cheap and have a 4 nanosec t_rr !  Just choose a few such types with a digital multimeter in the diode test range and check them for forward voltage to be within 15-20% to roughly double or triple the current limit of one by connecting two or three in parallel. And three in series already have about 250-300V reverse voltage rating, of course their forward voltage drop also triples but for testing higher than 100V pulses, a 2.1V or so voltage loss is negligible.

rgds, Gyula

EDIT Will comment your latest letter tomorrow, thanks.

[Jimboot]

@CP I couldn't do a great test of without multimeter as I am trying my new circuit with schottky rectifier & have not yet tuned it to run as a charger. However without the multimeter attached for 3.5 hours the voltage dropped .002V . Fairly inconclusive. When I get it going up 002v every 15 mins like I did the other night, I'll disconnect the meter & do another test.  I chose these schottkies  with http://jaycar.com.au/productView.asp?ID=ZR1020&CATID=33&form=CAT&SUBCATID=388 . The circuit seems to run a bit faster. More tests tonight & hopefully get back onto my Orbie (Ossie/Orbo hybrid ) This is the scope shot with the new circuit.

[Jimboot]

@cp currently running a test. Multimeter off & running at 297RPM start of run voltage at 1.403 will report back in 10 mins.