Help with Teledyne Geotech 50.1 wind speed sensor

[Speo]

Hello,



I got this Teledyne Geotech 50.1 wind speed sensor from ebay and I'm trying to figure out how it works. If you know anything about it, or if you can figure out something about it, please let me know.



I was hoping the unit is using a reed switch, or is generating a tiny current, so I can count the number of clicks per minute, or measure the current to find the RPM, but I wasn't that lucky.



This unit has lots of electronic components (looks to me like high quality) embedded in a transparent silicon cylinder (#5 in the image below) and it has 3 connectors at the back:

1)+12V

2)Ground

3)Not marked



I applied 12V DC to the unit, I turned the shaft and measured voltage, microamps and ohms between the 1st and 3rd wire and  between the 2nd and 3rd wire, but there was no reading of any kind(just some voltage going up/down even when not spinning, probably caused by a capacitor charging?).



Maybe the unit is broken, or the output is far more complex and requires more complex equipment to be interpreted.



Below are few images of the unit taken apart:



When assembled, the wheel #3 gets attached to the shaft inside the cover #2 and the wheel #4 sits inside the wheel #3. The wheel #3 spins around the wheel #4 which is static.







Below is the side view of the wheel #4. It looks like there is a small sensor in the middle of wheel #4, which somehow detects the wheels movement.....











The shaft has 2 small ball bearings and after giving it a good spin by hand, it spins for quite a while, the wheel #3 making a nice little flywheel.






My next step would be to remove al the electronics and add a magnet and reed switch and a bicycle speedometer to measure the cups rpm. I hate to not use all those original components.



Thanks,

Speo

[Kevin L]

  The electronics look really old on that unit and capacitors do go bad over time.   You could try replacing the capacitors and the transitors.  Personally I would just connect a step down transforer to one leg of my mill, and put a half wave brige on it.  You will get a signal that way that tells you exactly what the windmill is seeing.

[Flux]

Probably a capacitive sensor, it looks as though those slotted cups are aluminium.

I guess there is an oscillator in the circuitry to produce a carrier frequency to operate from the proximity of those slotted cups. I would expect some form of output from the 3 rd wire to ground. If you have a scope, check with that as it may be a modulated carrier which may not make sense on a meter.

The potting strongly makes me think it is capacitive.

If it is dead then someone has almost certainly done something silly and put it up for sale.

Flux

[tecker]

Looks like some nice hardware the electronics has some  power hungry componants so the bike speedometer look like a good Idea .Wire extention and a divide counter will get  you in the house with some another device to calibrate.

[TomW]

Speo;

You may want to ponder using the guts to a computer mouse. Some minor mods to the slotted cup parts and the optical encoder bits of the mouse could get you counting pulses you could read. The rest is just math.

Maybe.

Kinda.

Cheers.

TomW

[tecker]

Your talking about the diference between

looks like 6" and 26" so may be a divide by four

with a 74HC4059 you should get in there with two ics and a resistor ( not sure what  logic level the hall device inputs the display unit should be 3 to 5 volts ) You'll have some fudge factor with the two ics .

Don't use a reed switch they get flaky fast.

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/bincount.html#c1

[sPuDd]

Speo,

   get hold of an old VCR. Most have a pancake style

capstan motor which is perfect for anemometer work.

They have a large side load bearing, are 3-phase wired

and some have hall effect, optical or inductive prox

RPM outputs. The motor coils alone will give good output

levels for measuring wind speed. And the shaft is about

3-5mm diameter and quite long. Great for mounting cups on.

Below:

I used some schottky diodes to make a 3phase rectifier

as I wanted to see what power was available from the motor.

You can see that apart from the 4 motor connections (M)there

is quite a few others. This motor has a pickup that comes

from the saw tooth unit in the next pic.

Below:

You can see the saw tooth platter that provides a very

accurate line of pulses for every rotation.

Oh, and old VCR's are give away items too

sPuDd..

[Speo]

Kevin, Flux,tecker, TomW, sPuDd, thanks for all your instructive answers and cool ideas.

I will keep you posted with the result of this little project.

Speo