is harnessed, and may spur future VAWT design and research. The study on the enhanced performance of the wind turbine is also given by incorporating drag devices.

WIND TURBINE DESIGNTheoretical analysis The belt drive system consists of several parts of the belt drive calculation and the V–Type belt is considered in this study. Thus the main calculation that has been done at this system are angle of wrap for small and large pulley, belt length, pulley speed, the tension ratio and the power transmitted by the belt. The structure of the V-belt is shown in Fig. 1, which illustrates the main parts in V-belt such as the large pulley diameter indicated by the number 3 and the small pulley by the number 2 and the angle of wrap of large pulley indicated by θ3 and small pulley by θ2. C indicates the centered radius between large and small pulleys.

Angle of wrap for large pulley

Angle of wrap for large pulley is defined as (Joseph et al., 2004)

o-1?180?2sinθ3D3-D2 (1) 2CUsing large pulley diameter D3 as 30.48×10-2m, small diameter D2 as5.08 ×10-2m and the radius C as 0.3048m in Eq.(1), the angle of wrap for the large pulley is obtained as θ3 = 229.25°.

Angle of wrap for small pulley

Angle of wrap for small pulley is defined as (Joseph et al., 2004)

o-1θ2?180?2sinD3-D2 (2) 2CUsing the same values as mentioned above in Eq.(2), angle of wrap for the small pulley is obtained as θ2 = 130.75°. Centered radius length

Centered radius length is defined as (Joseph et al., 2004)

(D3-D2)2π (3) L?2C?（D3?D2)?24CUsing large pulley diameter D3 of 30.48 × 10-2m,small pulley diameter D2 as

5.08 × 10-2m and the centered radius C as 0.3048m in Eq.(3), the radius length is obtained as L =1.221 m.

Tension ratio tide side over slack side

Tension ratio of tide side over slack side is defined as (Joseph et al., 2004):

TT12????3???ln??（4） 2.3??where, the coefficient of belt friction μ is 0.25, θ3 is the aforementioned angle of wrap of small pulley in radians (4 rad), T1 is tension at tide side and T2 is tension at slack side. Using the values as mentioned above inEq. (4), tension ratio of tide side over slack side is obtained as T1/T2 = 1.545. Tide side belt tension

Tensionof tide side is defined as (Sorge, 1996) T1 = Wg (5)

By choosing the total weight W of the upper part of turbine as 17 kg and adopting gravitational acceleration g as 9.81 m/s2inEq.(5), tension of tide side is obtained as T1 = 166.77 N.

Slack side belt tension

Using the value of T1 inEq.(4), tension of slack side is obtained as T2 = 107.94 N. Pulley velocity

Velocity of pulley is defined as (Joseph et al., 2004)

V??D3N60 (6)

Power transmitted by the belt

The power transmitted by the belt is defined as (Joseph et al., 2004) PB = (T1 – T2 )V (7)

Using tension at tide side T1as 166.77N, tension at slack side T2 as 107.94N and pulley velocity V as 2.84m/s in Eq.(7), power transmitted by the belt is obtained as PB = 167.08 W.

Prototype design

The components of the 1/3 scaled vertical axis wind turbine are designed by using the CATIA software in the Structural Laboratory in Unisel and assembled together to predict the full scale. The wind turbine is a three bladed with tapered wing sections connected to the rotor of the generator and has been tested at an open hall. The corner sharp has been used as aerofoil for the wind turbine blade by producing a controllable aerodynamic force with its motion through the wind flow as shown in Fig.2. The other main components that have been designed and used to construct the wind turbine are described in the following sections.

Base and Base Table

The base material has been chosen as steel since it stands 6096 mm high and weighs 15 kg, and on its ownthe base does not support the torque and moments produced from the wind turbineso a base extension and a connecting bracket have been designed. To connect the 4 sheets of steel bracket to the steel base a bottom bracket made of 38.10 mm × 762 mm steel has been used.The 38.10 mm × 38.10 mm structure provides quick assembly and disassembly of the turbine base structure.

The bottom bracket requires four simple corner welds and flat head bolts welded in position that encourage quick assembly. Four sheets of 1219.20 mm×2438.40 mm ×19.05 mm have been used to construct a base extension that gives a larger footprint on which weights are placed. The main sheet is oriented with two sheets side-by-side, with two other sheets on top at 90 degrees rotation to the bottom two sheets. This creates a base table of 2438.40 mm × 2438.40 mm dimensions as shown in Fig.3.

Shaft and Bearings

The shaft used in this design is the type of polishaft and its weight is 14 kg, being made from steel. The diameter of the shaft is 30 mm and its length is 2133.6 mm. Its surfaces are very soft and make the shaft rotation very smooth when attached to the bearing. Minimizing the required start-up torque is essential for the wind turbine to self-start and thus, the success of the project. The bearings that are used in the wind turbine design are not salvageable.Bearings are very expensive, and for the particular setup two roller bearings have been used that are primarily centralized with the shaft. This combination provides the least amount of friction, while maximizing bearing life and maintaining safe operating conditions.The diameters of the bearings are 88 mm and weights300 g each.

Support Arm and Drag Device

Steel is used for the three support radial arms to maintain a lightweight assembly with minimal inertialmoment,and centrifugal forces. The connecting arms provide a means to mount the blades to the center shaft.A drag device has been made from a lightweight plastic (casting plastic) and mounted to the main shaft. The length of the drag device is about 762 mm and width is 182.88 mm. Wind Turbine Blade Design

The top and bottom of each blade is a 1066.8 mm ×139.7 mm ×50.8 mm deep rectangular section to allow for easier connections to the radial arms and passive pitching system. In this study the corner sharp has been selected as the shape of the blade for its very high capability to face the resistance of wind flow and faster rotation during the wind flow.The final assembly of the wind turbine has been set at Thermal Laboratory in University IndustrySelangor and is shown in Fig.4. There are 18 parts and 15 screws combined together in the assembly process. The shaft is connected to the main parts and to the alternator during the full assembly of this vertical axis wind turbine.

Experimental Procedure

The prototype of the Unisel wind turbine is installed at the Thermal Laboratory in University Industry Selangor and a number of preliminary tests have been carried out on the device,which has operated successfully.Before starting the operation,the battery terminal and alternator terminal are checked properly and it is connected with the lamp and switch. Then the wind turbine is allowed to rotate.Due to the rotation of the wind turbine blade voltage is produced and the connected lamps are turned on (Fig. 5).