Cumulus Support

My anemometer is stuck for nearly a week now. Below zero temperatures and unusually high humidity (together with day-long fog periods) produce this:



This is an older picture of the anemometer; because of the fog it’s barely visible at the moment. It sits on top of a power pole about 10m above ground, so it’s not easy to “give it a push”. I’m sure it will start spinning again as soon as the sun comes through sometime later this week ...

Anyway, has anybody any experience or suggestions with lubricating this thing to prevent the freeze up? I know WD40 is not so good at lower temperatures. How about silicone spray? Or should I just leave it alone?

Hi Karl,

Note that Fine Offset have now changed the design of the anemometer so that there is a larger gap between the rotating and stationary parts. For example, see the Maplin Spare Part, but sadly they don't export from UK and I've never seen anybody else sell it at such a low price.

But if wonder if any design (or the vane) can resist that degree of frost. Perhaps a "hydrophobic" spray such as WD-40 or "Rain-X" (primarily intended for car windows) could help, but it will presumably need to be applied at least before every winter.

Cheers, Alan.

I was thinking that it might be an idea (good or bad, dunno ) to get some heating elements retro fitted somehow.

Hi,

Well, the FO wind sensors are easy to dismantle, so you could simply insert a "watty" resistor or perhaps a small car/auto bulb. I don't know the optimum power, but perhaps 2 watts (for each sensor) might be enough.

However, it would be necessry to run a "power" cable, which rather defeats the "wireless" feature of the station. Also, by running a ("grounded") cable up to the wind sensors you would be potentially creating a "lightning conductor", so some caution is required.

But before somebody suggests a solar panel, I've just estimated that you'd probably need around 1 square meter! It happens that the Latitude of Bridge Lake (51 degrees) is almost identical to mine in London, so it was easy to check (in Cumulus) that the peak mid-winter illumination (with a clear sky) is 250 watts/m2 (if the panel is tilted at 50 degrees), say 150 watts for an average of 4 hours a day. With a 15% panel efficiency that would be less than 4 watts continuous, averaged over 24 hours.

Of course you'd (also) need a backup/standby battery, but even a car battery would be only good for less than a week (say 600 watt-hours) without charging.

Cheers, Alan.

It would be useful to free it sooner than later. My unit started sticking at low wind speeds so it wouldn't turn but was ok once the wind got up. It eventually seized totally and before I could get to it we had some severe gales which ripped the cup section totally off the sensor and landed in the field next door. The resident cows took a liking to it and chewed two of the cups off.

I have just taken delivery of a replacement unit plus a spare just in case of future problems.

Just need the wind to die down enough to get out and drop the pole, swap the units and get it back up again.

It's working again. A little sunshine, a little wind ... Still heavily covered in icicles, so I don’t know how reliable it is at the moment.
I guess I will check out some method of "heating" like Alan suggested as soon as I can get to it next spring.


(Click to enlarge)

My N96FY anemometer stopped after two months, not ice but a wind gust. I don't know if it snapped or bent something.

Maplin mail order will arrive by the weekend and I'll just replace it and then see if anything can be salvaged for spares.

Mine stuck in mildly freezing conditions almost immediately after it was installed. I used WD40 on it at that time, which resolved the problem, and I have had no problem since. Third winter now and recent temperature was -16C with no negative effect.

KarlS wrote:I guess I will check out some method of "heating" like Alan suggested as soon as I can get to it next spring.

Well, you've got no shortage of 'free' power there!

mcrossley wrote:Well, you've got no shortage of 'free' power there!

Ahhh Mark, you're right about 'no shortage' (at least most of the time), but I wonder about the 'free' part. I'll have to talk to the local power company about that.

I found "PB™ Penetrating Catalyst" to be a superior lubricant for the purpose. Available everywhere.
"...displaces moisture, does not evaporate. It remains on the surface as a lubricant and rust inhibitor."
http://www.blastercorp.com

If you leave a gap when reassembling instead of snapping it all the way back on, you can avoid the frozen surface tension problem.