Adriaan Kragten has tested one of his small alternator designs and published results showing it is compatible with a 1.02m diameter rotor for a low power wind turbine.
A new chapter 6, “Generator measurements”, has been added to public report KD 678. A teacher of a technical school has built the 8-pole generator of the VIRYA-1.02 and I have measured this generator on my test rig for a 12 V battery load. The torque level of the generator appeared to be lower than expected but the matching in between rotor and generator is still acceptable. The maximum electrical power for the rated wind speed of 8 m/s is about 24 W.
Hi, I have my own Piggott wind turbine for 2 years, a 180cm 350W. I had some trouble about the way a regulator adapts energy to a battery charger or a injector. So I made my own regulator, which is a real MPPT for wind turbine and costs less than 50€. May be you will be interested, so here is the link :
There are many regulators on the market. However they are mostly adapted for solar panels only, and if the curve of delivered power is similar, the way to regulate is different – to resume solar panels use buck converter, wind turbines use boost converter. Many are not MPPT, the PWM regulators are very less efficient than MPPT, and also specific wind turbine MPPT regulators are very expensive.
So, It can be a very good project to self-build our own regulator, after having been built our own Piggott wind Turbine
Adriaan writes: “I have added a new chapter 6 to report KD 645 in which a 10-pole PM-generator is described using the housing and shaft of an asynchronous motor frame size 80. This generator has a stator with no iron in the coils. The tittle of this new chapter is: “Alternative winding with 15 coils”. The original winding is a 1-layer winding with six coils which are laid in twelve outside grooves milled in the Delrin stator bush. The alternative winding has fifteen coils which are laid in thirty, 8 mm holes which are drilled in the Delrin stator bush but this requires a totally different way to lay the winding. De Delrin bush is much stiffer for holes than for grooves so it can be pressed in the aluminium motor housing. I think that more copper can be laid in 30 holes than in 12 grooves and so the winding is more effective. I picture of the original winding is given in figure 1 of KD 645. A picture of the alternative winding is given in figure 3 of KD 645.
Adriaan would be delighted to hear from anyone who wishes to build prototypes. He has a lifetime of experience in the field of small wind turbine design but lacks facilities to do this practical testing at present.
Being off the grid I don’t need to worry so much about “payback” since I do not pay for mains electricity in the first place and the payback to me is immensely more than cutting my running costs. But I was reading the blog of Bill in Monmouthshire who has been running a PowerSpout for six years and has a lot of useful insights to share.
Bill points out that “there is a benefit unique to very small hydros operating 24/7. Putting out power at the relatively low level of 500 watts (+/- 300), the turbine’s output closely matches the base load demand of a property. Base load is made up of that multitude of appliances which are ‘on’ all the time – from battery re-chargers to fridges, freezers, central heating pumps, computers and so on. Totted up their power requirement can typically be 400 watts. That translates over a day to an energy consumption of 10 kWh.”
Whereas solar PV generates great lumps of energy in the middle of the day when people are out at work (so the house demand is low), hydro carries the load 24/7, and meets your needs directly. Solar energy will mostly be exported to the grid (exceeding the demand) but hydro power is mostly available to use (without buying a battery).
His hydro turbine really does have impact on Bill’s electricity bill.
Actually the same logic applies to off-grid sites in fact. You probably want a battery to maximise your usage of the resource and allow you to run a normal home off a hydro that only produces half a kilowatt of power. But the battery can be much smaller than I need, with my wind and solar systems. I wish I could have a hydro but there is no suitable site near my house.
I have started a Scoraig Wind Electric Facebook page that will only be about renewable energy stuff. (My personal Facebook has some pics of wind turbines etc but also plenty of grandchildren and dogs etc so this will be a better page for people who are more interested in generating their own power from hydro, solar and wind energy.)
Adriaan continues to add to the impressive list of reports that are free to download from his web site. These provide a valuable resource to students or designers working on small wind projects.
sent to me by: Dave & Mary Lahar, Northeast Kingdom, VT, USA
4.6 m (15’) axial with power furling
26 m (85’) guyed tower
The furling actuator is mounted in the base
of the tower. It is 12VDC, travels .46 m
(18”) and is rated at 68 kg (150 lbs). It
has a built-in potentiometer feedback allows for position control.
The actuator pulls on a 4 mm dyneema line
to furl the tail through a pivoting snatch block, like those used on many PTO
tractor winches. Dyneema is very strong,
light-weight and has virtually no stretch.
A small sash weight keeps the line taught, and the tail is free to furl
independently.
When the winds are predicted to be
unusually high, or rough (or both), or when we have ample solar production we
can easily shut things down manually. This is by far the softest method –
furl the tail, and close in the (resistive) load bank – now we’re ready for
most anything that comes our way.
The furling actuator is also controlled by
the charge controller whenever the input voltage gets above a user-selected
pre-set. It is a simple dry-contact
relay action.
We originally had a small hand winch to
operate the tail, and that worked fine.
This arrangement allows things to be controlled from the house. When the wind gets unruly, as it regularly
does, or the PV is ample for the loads, it is nice to be able to save the wear
and tear on the turbine. The actuator
has been in place now for about two years and has worked very, very well for
us.
Thanks again for all your inspiration and
we hope this may be of use to some of your readers.
A friend has suggested that I flag up the consultation that is taking place in the UK about this new method of support for grid-connected renewables including wind and solar.
“I think this is an important consultation for small grid-connected wind, because the potential for time-of-day and even spot market export tariffs could make owning a turbine much more attractive for crofters, farmers, small businesses, and communities.”
From: Mike Allen
Subject: Re: A Wind Turbine Recipe Book
Date: 12 April 2013 10:53:18 BST
To: jytte
I recieved the book yesterday and when it arrived I thought ‘this isn’t worth £12’.
But how wrong I was once I’d opened the envelope and settled down to read the contents with a cup of coffee. 3 hours later the coffee was stone cold and I was still reading the book.
Loads of info to be getting on with.
I’ll email Hugh when my terbine is up and running with some pics.
