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Why is the wind generator so powerful for its size, weight and cost?
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Almost every part of the Air X turbine has been developed from “the ground up” using 3-D computer models to help analyze every element of the design. As a result, this state-of-the-art turbine features the following:
• The AIR-X is the only small battery charging wind turbine that uses a microprocessor to track the cubic power of the wind and adjust and stall the permanent magnet (PM) alternator accordingly. Other PM alternators are linear in their output and either stall or unload the rotor blades making them very inefficient.
• The AIR uses 12 Neodymium Iron Boron magnets, which are the strongest magnets available in the world.
• This is the first wind turbine to use blades with advanced airfoils made of injection-molded carbon-composite materials that meet the strength-to-weight ratio requirements of this computer assisted design.
• The microprocessor controlled circuit and alternator allows the turbine to self-regulate in high winds and to automatically stop when the batteries are charged.
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How does the wind generator regulate my batteries?
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The internal circuitry of the Air X monitors the voltage at the output of the turbine. When the maximum charging voltage is reached (adjustable by the potentiometer on the side of the turbine) the Autobrake is engaged. This cuts off the turbine output, and the blades are braked to a slow rotation. The Autobrake remains on until the voltage drops to a level slightly below that of a fully charged battery (12.75V for 12V, 25.5V for 24V) At this point the Autobrake releases and the turbine resumes charging.
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Can the output of the wind generator be changed by the potentiometer?
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The AIR-X produces 100% of the power of which it is capable according to the wind speed. The potentiometer only changes the voltage setting at which the Autobrake engages. Changing this setting will not increase the ampere output of the machine but may overcharge your batteries.
w solar panels have a manufacturer's warranty of 20 years. With proper care, however, the panels should last many years beyond the warranty. In the case of batteries, basic routine maintenance and discharge rates of no more than 10 -20% means your batteries should function effectively for 10 years or more.
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How does the wind generator control power and RPM in high winds?
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The microprocessor in the AIR-X constantly monitors turbine RPM, and is programmed to stall the blades in high winds. The blades are put into a low efficient region which drops the turbine to roughly ¼ of its peak RPM. This allows the turbine to survive high wind events with low mechanical stresses. Also, since the blades are running inefficiently in stall mode, they are not delivering substantial power to the electronics, and the alternator and the power electronics remain cool in stall mode. When the microprocessor senses that the wind speed has dropped, it will release the AIR-X from stall mode, and normal charging will resume.
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What is the maximum wind speed the wind generator will survive, and should it be taken down in a storm?
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NEVER approach the AIR or any turbine in strong wind conditions. The AIR is designed to run without attention in storm conditions; however, if you wish to shut down the turbine you can do that remotely as described in Section 3.1.5 on page 12 of the AirX User Guide.
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How long will the bearings or other wearing parts last? |
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According to engineering calculations:
- The bearings should have a 10-year life in 12-mph (6 m/s) average wind speed sites. Bearing life will vary from one application to another; however, you should expect at least a five-year performance in adverse conditions and 10 years in normal conditions.
- The copper brushes should last a lifetime. The yaw shaft has been tested to over 100,000 revolutions with no visible wear on the brushes or slip rings.
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Why is the a cut-out in the tail of the wind generator?
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The cutout helps to balance the AIR on its turning axis to better track the wind and to give it stability in rough seas. This balance keeps the turbine pointed into the wind even when the boat is heeled over. Since the turbine is properly balanced, more power can be extracted from the wind no matter how slight or directionally unstable.
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Can the wind generator be connected in reverse-polarity to the battery without causing any damage? |
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NO! If you connect the turbine in reverse-polarity to the battery you will damage the turbine and void your warranty. Make sure to connect the positive (red) wire to the positive post on the battery, and connect the negative (black) wire to the negative battery post.
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Will it hurt the wind generator to short-circuit the output? |
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No, the AIR-X is designed to be short-circuited as a normal shutdown procedure. The function of the stop switch is to both disconnect the turbine from the batteries as well as short-circuit the output of the turbine. BE SURE NOT TO SHORT YOUR BATTERIES!
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Will a stop swith not short my batteries? |
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When a single pole, double throw switch that is rated for proper current and voltage is connected as shown in the manual, the turbine positive is disconnected from the batteries BEFORE being connected to negative. It is important that your stop switch be of the type that opens the circuit between positions. This is commonly referred to as a “break-before-make” switch. Be sure to install a fuse in any case.
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How do I know the wind generator is charging? |
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For a precise indication of charge current you will need to install an amp meter in your system. The meter or meter shunt should be installed in-line on the positive wire. The meter should be located on the wiring between the stop-switch (if used) and fuse or breaker. Southwest Windpower carries a 0-30A, analog (needle-reading) meter that may be purchased directly if one is difficult to find in your area.
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I can measure a small amount of current back-feeding to my wind generator. Is this normal? |
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The AIR-X internal circuitry consumes a maximum of about 20 mA when it is not charging. This is about the same current draw as a small clock. If you are concerned about this small amount, you can install a stop switch and switch to “OFF” to disconnect the turbine.
If you observe your turbine oscillating in the manner described above, check the fuse or breaker for the turbine as it may be expired.
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I'm not ready to attach my wires from the wind generator to the batteries. Can I leave the wires unattached? |
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Always short the AIR-X negative to positive when it is disconnected from your system, and the blades are installed. BE SURE NOT TO SHORT YOUR BATTERIES! The turbine will prevent itself from over-speeding and over voltage, but as explained above, this is a high-wear condition for the turbine and should not be left that way for any substantial amount of time.
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Multiple tubines make up my system and they seem to function erratically. Why? |
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Check your wire sizes to be sure they are at least as big as those specified in your AIR-X marine manual (bigger is always better, but more expensive.) Be sure all of your wire connections are very solid, have no gaps, have no corrosion, and no crimp terminals are used. If your turbines are at various distances from the batteries, make sure turbines with longer wire runs have bigger wires.
There will be some variation at what voltage turbines will enter into regulation based on the relative wind to which each turbine is exposed. Small differences in line loss can be significant in strong winds.
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Can household AC fuses or breakers be used to fuse the generator? |
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You should only use DC rated devices with your AIR-X, as AC components are typically sized differently. Because DC breakers and fuses in the required sizes may be hard to find in your area, Southwest Windpower carries a 30A and 50A breaker <link to breaker in store>.
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Can an external charge controller be used to regulate the generator?
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It is recommended to use only diversion load type charge regulators<link to regulators in store>. These regulators divert excess power to a heating element or power resistor when the batteries are full. This excess power can be used to assist in hot water or room heating. PV type regulators should never be used. Series type regulators that disconnect the power source when batteries are full will often give undesirable results such as causing the Autobrake to fluctuate on and off when the batteries become full.
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My wind generator is installed with an automotive-style amp meter, but I don't see any current. Why?
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Given that all wiring has been done correctly, and other precautions have been heeded, chances are that the amp meter is wired backwards and the needle is attempting to move in the negative direction. If “zero” is on the left-hand side of the meter, then the needle cannot move and looks as if the unit is not producing. Simply reverse the leads on the meter and see if current will register.
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Where can I locate tubing to make a tower?
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The AIR-X marine uses 1 1/2” schedule 40 steel pipe. (Actual outside diameter (O.D.) of the pipe is 1.875 inches, 48 mm) Steel pipe is available at any hardware, fencing, or plumbing store. Aluminum pipe can be found at most electrical hardware stores. Ask for electrical aluminum conduit.
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The recommended wire size for the generator seems small for 400 Watts output. Why is that?
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Because the output of the AIR-X follows the cubic power in the wind, the output increases rapidly with increasing wind speed until over-speed stall occurs and the output power drops off to about 75 watts. The wiring could be sized for the maximum current output of the turbine, but this output is seen primarily in gusty conditions.
We have recommended wire sizes that are intentionally small to save the customer from spending a lot of money on wiring, while still experiencing no more than a 5% annual energy loss due to resistive line losses. In most cases this will be acceptable for local electric codes – please contact your installer or local electrician to be certain of your area’s specific requirement.
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What is the difference between copper and aluminum wire?
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Aluminum wire is less conductive; so generally it must be bigger for the same amp load and resistive losses as copper. The AIR-X uses copper or tinned copper for the yaw wires.
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What is the difference between welding cable and standard stranded cable?
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Welding cable is typically very finely stranded to be very flexible, where as standard cable will typically hold its shape. Always be sure that the environmental rating of the insulation of your power cable matches the application.
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Why does the wind generator regulate before my batteries are fully charged?
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This can happen if the AIR-X is connected in parallel with another charging source, and there is some distance between this connection and the batteries. The other charging source can create a voltage drop because of its own current output, which will raise the voltage that the turbine “sees”.
Be sure to check ALL of your wire connections. All connections should be soldered, split bolted, or secured in a terminal block. CRIMP-ON TYPE CONNECTORS MUST NEVER BE USED! These are poor connectors for high currents and will almost always have some resistance at the male/female connection that will increase your voltage drop and line loss.
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How does wire sizing or voltage drop affect the regulation of the wind generator?
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Due to the smart controller of the AIR-X, wire size should not have a large effect on the regulation. The AIR-X uses the power lines to sense battery voltage, but before measuring the battery voltage, the AIR-X will momentarily stop charging. This allows the turbine to make a voltage measurement with no line loss in the system. This is an improvement over the AIR 403 which can only measure the battery voltage plus line loss in the system. The voltage measurement routine takes place periodically as the batteries approach the regulation set point. Output is cut for a fraction of a second, and the whole process will not be apparent from the outside. It will not affect the net energy generation of the turbine.
At a minimum, the Air X manufacturer, Southwest Windpower, recommends using the wire size listed for your system in section 3.1.2 of the owner's guide <link to owner's guide> to avoid power transmission losses.
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What kind of batteries should I use with the wind generator?
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Only batteries intended for power system applications should be used. <link to T105 in store> This means “deep cycle” type batteries, and not the Marine deep cycle type as these are not intended for the same application. Typically “true” deep-cycle batteries will be rated in amp-hours and have some indication of the number of charge-discharge cycles that are available. Beware of the dubious claims of “deep-cycle” claimed by the manufacturers of inexpensive batteries.
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Why shouldn't I use automotive batteries in my DC system?
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Automotive batteries are meant to discharge a large amount of current in a very brief time. The lead plates are thinner and often porous to allow rapid discharge. They will also wear faster and are not intended to be discharged far below their normal voltage. True deep cycle batteries are intended for more moderate loading and deeper discharge, and are made with thicker, longer lasting plates. The casing and construction of batteries intended for renewable energy systems is typically much tougher and of higher quality than automotive batteries.
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Is lightning protection necessary?
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Lightning protection is ALWAYS a good idea when erecting a metal tower. The Delta Lightning Arrestor (model LA 301-DC) <link to arrestor in store> is widely used in outdoor power and antenna applications. While this is still no guarantee that Mother Nature wont find a way, these arrestors are not very expensive and may save some very expensive equipment.
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What effect does radio interference have on the wind generator?
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The internal circuitry of the AIR is shielded and filtered to prevent radio interference, and has been tested to insure electro-magnetic compatibility.
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What effect does the wind generator have on radio transmissions?
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The AIR-X normally does not affect radio transmitters. Care should be taken, however, to route power lines from the AIR-X away from the power and antenna lines of a radio transmitter. An old ham radio operator’s trick is to twist positive and negative wires together to provide an even distribution of EMF noise across both wires, which serves to cancel out the electrical noise created. This technique can be used on the AIR-X power lines, on the radio’s power lines, and on transmission wires. Transmission lines should always be kept as far from power lines as is practically possible. Proper grounding of the AIR-X and other system components must also be observed.
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Will the installation of an RF (radio frequency) filter affect the regulation of the wind generator?
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An RF filter should not affect the regulation of the AIR-X, but any electronic devices placed in line with the turbine must be rated for the proper current and voltage. It is best to place any line filters on the power lines for the load device (transmitter) that requires it, and as close to the device as possible.
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