Rotovector

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DaveS
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Rotovector

Postby DaveS » Wed Feb 06, 2019 1:34 pm

I'm steadily working my way through the extensive defects list for the new (to me) boat, and starting to think about some of the less essential, but nice to have issues.

The wind instrument isn't working. The masthead unit is a rotovector: a three cup anemometer with one cup elongated so that rotation speeds up and slows down each revolution, with the electronics working out from this the apparent wind angle. I've had one of these before and it seemed to work OK. My question is, with the mast down can I find out if it's working by attaching a meter to the wires and spinning it? If working would I expect to see volts (DC or AC)? Or should I use a resistance scale and see if the reading changes? Obviously I could try each of these in turn, but it would be helpful if I knew what to expect. Anyone know?
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pagoda
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Re: Rotovector

Postby pagoda » Fri Feb 08, 2019 9:48 pm

How many wires are involved - going up the mast?
8 or more? (12vDC, ground and 3 pairs)

If so , it is likely to be an " old school" three phase DC potentiometer, with the proportions of wind direction calculated from the three components of the the wind vector. Does wind speed from the Cups itself still work?

Graeme

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cpedw
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Re: Rotovector

Postby cpedw » Sat Feb 09, 2019 10:17 am

I vaguely remember a DIY version described on the web more than 10 years ago. A bit of digging found this http://web.archive.org/web/20111022163351/http://home.alphalink.com.au/~derekw/anemometer_diy/anemain.htm and the drawing of the sensor http://web.archive.org/web/20091009075410/http://home.alphalink.com.au/~derekw/anemometer_diy/snsdrg.gif seems it uses a fixed LED and detector with a slotted disk on the vane shaft to measure rotor speed. So power to the LED and pulses from the detector should be it. All assuming the one you've got works just the same way! I'll let you investigate further.

Derek

edit Further browsing found this http://web.archive.org/web/20091009082237/http://home.alphalink.com.au/~derekw/anemometer_diy/anepcbc.gif I think the small circuit in the top right shows the connection to the vane. Seems it's 2 wires, both to power the LED and return the pulses. Simple if you get the polarity right!

And the whole circuit for the vane http://web.archive.org/web/20100620020601/http://home.alphalink.com.au/~derekw/anemometer_diy/sensorbd.htm

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DaveS
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Re: Rotovector

Postby DaveS » Sat Feb 09, 2019 6:26 pm

Thanks for the replies. I'm fairly certain there's just two wires going up the mast, so that would tie in with the DIY diagrams. I suspect that sorting this is going to have to wait until the mast is back up, but I'll have a look with an ohmmeter first.
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