The Ossie motor

[Jimboot]

Thanks @woopy, @futuristic @mags. Ok I have some wires to close to the rotor for sure. I will get some caps today. Motor back at 1.20 this morn. 83 hours.

[gyulasun]

...

Here enclosed the current test with a 100 ohm resistor at the entry . The motor spins much slower as expected  and the trace is much better on the scope.

and now the question  what does exactly shows this trace ??  pulse output from battery or pulsed input to the battery       is it showing the voltage or only the image of the current ??

Hi Laurent,

To answer your question, I assume you clipped the crocodile ground clip of the scope probe to the 100 Ohm resistor's leg that continues in the wire going towards the coils via the reed switch and the tip of the probe was tied to the resistor leg that went directly to battery positive pole, ok?  If this is so, then what you see in the scope shot picture is the voltage drop across the 100 Ohm that is caused by the current going into the coils when the reed switches are ON, so it is the pulsed output current from the battery. The pulse shape you see is a voltage amplitude but the real current shape is the same because on a pure Ohmic resistance that has but a little reactance the current shape is preserved in the voltage drop shape.

(The peak current is roughly: 1.5V/100 Ohm=0.015A multiplied by the duty cycle.  I averaged the peak V_b=1.92V from the scope shot as 1.5V because the triangle goes from roughly 1V to 1.92V and the rest amplitude from zero to up the 1V under the triangle must be added to the 0.5V averaged from 1 to 1.92).
Your duty cycle is about 23msec/118msec=0.19 (pulse duration/period of a full pulse)  This gives an avarege current of 0.015*0.19=0.0028A i.e 2.8mA

From your 1 Ohm current measurement scope shot, previous page, the peak voltage drop V_b=50.4mV,  using roughly this value gives 50.4mV/1 Ohm=50.4mA and when multiplying this with the duty cycle, 11msec/60msec=0.18  it gives 50.4*0.18=9mA average current consumption.   These calculations are approximate because the pulse shapes are not clearly rectangular.

Supercap: if you have the exact type and manufacturer of your supecaps, then surely there must be a data sheet that includes the equivalent series resistance, ESR for them, look for it on the maker's site.

rgds, Gyula

[Light]

Thks Captain, yes it's drawing error, I followed schematic from Naudin site.
Will try with more magnets and load on rotor.
Thks.

[Jimboot]

@futuristic this was posted on the Yahoo EVGRAY list
"cooling fan motors usually have permanet magnets in them, and you can feel the notchy rotation to them as the cores in there line up with the magnets so there is some loss using a cooling fan motor as a chasssis unless that is differnt type of cooling fman motor with no permanent magnet in there.

Everythting sounded good, but at last part of pager Naudin says that its not OU

they need to try FWBR AC legs across the switching, and DC into 2nd battery stack.

Run on 3V and charge 1.5V paralell battery stack, or run on 6V and charge 3V parelell batteyr stack or 12V and 6V paralell or 24V anbd 12V paralell batteyr stack etc etc etc

DC from FWBR goes direclty into 2nd battery stack

ONE LEG OF AC LEG OF FWBR gets switched slightly delayed to the motor coil pulse - about 5 degrees retarded approx.

When this sweet spot is found, motor will race up in speed, draw will drop way down, and 2nd battery stack gets charged with as much power as what is running motor in first place if not more...good idea is to charge 4 batteries in paralell while runing on one or two...

charging the same battery that runs the motor, and not seperatre battery stack is always a touchy not "proof positibe" way to do it - voltage rise is not battery charge...but still, I bet using nicad or lithium ion batteries although is OU jsut as Ossie has it going now since they can charge up so fast and last so long on a charge and like those spikes to charge with more than lead acids.

I wonder if his draw to motor goes up when the charging occurs or stays the same with or without the charging.

ciaoK"

What do you think?

[Jimboot]

Just got home motor had been as low as 1.19 at lunch time it is now back up to 1.21 & bouncing back to 1.20. 90 hours running time