Wind turbine RPM's

[David HK]

After visiting this web site for several years and scouring the Internet and electronic books for circuits, I am about to start putting together the design for a poor man's DC powered RPM display for a wind turbine.

To help me with resistor and capacitor calculations it would be handy if readers could contribute facts or inspired guesses as to the RPM of their wind turbines until - or at - the furling point. If anyone has real RPM figures for runaway mills please let me know.

My circuit ideas are based on LED or LCD displays with commonly available IC's etc, but I am not touching programmable IC's for the moment. Nor am I forking out cash for hold in the hand RPM sensors which are available on the market.

I am aware of sniffing the AC component from wind turbines and working out the Hz readings from multimeters,but the aim is to have something that can be used for 'learning and setting-up purposes' even if it involves umbilical links down the 'pole'.

As far as sensors are concerned, I am using as many as I can for experimental purposes i.e. reed, slotted opto, proximity sensors etc.

I look forward to useful replies.

David HK

 

[Flux]

Anything you want unless you define a starting point. Rpm is mostly decided by blade diameter.

At the extremes for the size of things built here you could see speeds from 200 to 2000 rpm.

Just to take a specific case of a machine about 6ft diameter, a slow one could cut in at 150rpm, more typical could be 200 - 220 rpm, even up to 270 rpm is not unreasonable.

Full power at say 20 mph could vary from 300 - 600 rpm depending on the type of loading. No load runaway speed for a fast 6ft machine in a high wind could be in excess of 2000 rpm. More usually perhaps 1500 + rpm.

You can probably scale that with speeds inversely proportional to prop diameter and be reasonable. Even this doesn't cover extreme cases of tsr.

Flux

[David HK]

Flux,

Thanks for the contribution.

I am working and aiming on Hugh Piggots 8' (2.4 meter swept area dia) machine.

Your comments are very useful

Thank you.

David HK

[Flux]

OK can help better now.

Cut in 160 - 200 rpm depending on air gap and thickness of stator ( care in manufacture)

Speed at furling in the region of 400 rpm depends on voltage of system, battery volts and line resistance and also on air gap.

Runaway speed in high wind likely to be up to 1200 rpm and you will not want to be near it.

Flux

[David HK]

Flux,

Thanks for the prompt continuance of replies.

I had earlier thought that my parameters for RPM would be in the range of 100 (mimimum starting) to somewhere around 2,000 or 2,500 RPM which is more-or-less in the region suggested by your previous post.

Everything so far has been spot-on in terms of usefulness.

I am using some of E A Parr's electronics circuits as building blocks.

David HK

[freerange]

I would check out this  www alton-moore.net/wind_calculations_english.html

It gives you rpms at different speeds based on your inputs.

Ben