19-12-2012, 02:56 PM
Electricity generated by hand wheel
Electricity generated.doc (Size: 318 KB / Downloads: 77)
Stator-
The stator contains six coils of copper wire, cast in fibreglass resin. This stator casting is mounted onto the spine; it does not move. Wires from the coils take electricity to the rectifier, which changes the AC to DC for charging the battery. The rectifier is mounted on an aluminium 'heatsink' to keep it cool. The magnet rotors are mounted on bearings, which turn on the shaft. The rear rotor is behind the stator, and enclosed within it. The front one is on the outside, fixed to the rear one by long studs which pass through a hole in the stator. The wind turbine rotor blades will be mounted on the same studs. They will turn the magnet rotors, and move the magnets past the coils. Magnetic flux passes from one rotor to the other through the stator. This moving magnetic flux is what produces the electric power.
Stator construction
This section tells how to make a stator, using the jigs and moulds. It is a good idea to wind a coil before making the stator moulds, so that the mould can be checked for correct fit.
Winding the coils
• Mount the reel of winding wire on an axle behind you, in line with the coil former. The wire should form an 'S' bend as it winds onto the coil .
Bend the tail of the wire 90 degrees, at a point 100mm from the end. Do not handle the bend any other part of the wire; leave it straight. Bent wire does not make a compact coil.
• Place this bend in the notch, so that the tail hangs out.
• Twist the tail loosely around one of the butterfly bolts.
• Grip the wire between the reel and the winder in a piece of rag to keep it tight.
• Wind the handle of the crankshaft.
Preparations for stator casting
The stator casting will contain:-
• six coils
• polyester resin and talcum powder (and perhaps pigment)
• fibreglass mat (CSM)
• four studs of 8mm x 100mm threaded rod
Also, be sure to have the moulds prepared properly. Sand them, seal them, polish them. If PVA release agent can be got, then use it. Cut out pieces of fibreglass CSM, using the templates. There will be 2 circular disks for laying flat in the outer mould. You also need enough curved strip pieces to cover the inside wall of the outer mould in a double thickness of CSM. Overlap 25mm between pieces. When you are sure that you have everything to hand, start the resin casting process. It is a good idea to read through the procedure first, and check that you understand it all before you start. There are notes on polyester resins in section 8.
The stator casting procedure Diagram 30 shows the procedure for weighing out the resin and the talcum powder. The talcum powder is only used for bulk mixes (not thin layers with CSM), to prevent overheating, and to thicken the mix.
Rotor construction
The magnet rotor is also a casting. There is also a procedure later for assembling the parts. First collect together the magnet plates, magnet blocks, stainless wire rope, etc. as described next. Magnet plates Each magnet rotor is built on a steel disk, 6mm thick. See diagram 32. Do not use aluminium or stainless steel for this disk! The disks have to be made of magnetic material. The disk has holes to mount it to the hub - in this manual the hub has four holes, each 10mm diameter, on a circle at 4 inches (102mm) PCD. If a different hub is chosen, then all the jigs and moulds must match this hub. At the centre of the disk is a 65mm diameter hole. There should also be four holes drilled and tapped (threaded) for M10 rod between the magnet positions, at 220mm PCD. Screw four pieces of M10 rod, 20mm long, into these holes. These will bond to the resin and help to secure the casting onto the disk. 305mm
Rotor casting procedure
Before starting, check that everything is ready:
• the moulds are prepared with polish or release agent,
• the magnets and the magnet disks are clean and bright (no grease),
• 16 strips of CSM are ready to fit between the magnets
• the stainless steel wire is cut to length and taped
• the magnet positioning jig is ready
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals. It is made of a solid piece of semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.
Diode Construction
A diode is formed by joining two equivalently doped P-Type and N-Type semiconductor. When they are joined an interesting phenomenon takes place. The P-Type semiconductor has excess holes and is of positive charge. The N-Type semiconductor has excess electrons.Due to this difference, some of the electrons get attracted to the corresponding nearest holes and become neutral. This process takes place until an equilibrium is reached in the surrounding region of the contact surface. This leaves a layer with neutral charge of thickness nearly less than 0.1mm known as the DEPLETION LAYER. This layer is responsible for the development of resistance inside the junction Diode.