Journal of Power and Energy Engineering, 2013, 1, 6-13
http://dx.doi.org/10.4236/jpee.2013.17002 Published Online December 2013 (http://www.scirp.org/journal/jpee)
Copyright © 2013 SciRes. JPEE
An Experiment on Power Properties in a Small-Scaled
Wind Turbine Generator
Jee-Ho Kim, Hyun-Dai Yang , Kyu-Ji n Lee, Sung-Do Song, Sung-Hoon Park, Joong-Ho Shin
Department of Mechanical Design & Manufacturing, Changwon National University, Changwon 641-773, Korea.
Email: jiho2362@naver.com, neadai20@nate.com
Received September 2013
ABSTRACT
This study configures a simple wind tunnel using a blower for generating wind energy, which is equivalent to natural
wind, and a test system that measures properties of power. Also, the mechanical and electrical power in a small-scaled
wind turbine are empirically measured to analyze the relationship between the mechanical and electrical power.
Keywords: Small-Scal e d Wind Turbine; Vertical Axis Windmill; Gearbox; Mechanical Power; Electrical Power
1. Introduction
Environmental issues including ozone depletion have be-
come to the front because of exhausting natural resources
and carbon dioxide emissions according to sustainable
use of fossil fuels during industrialization processes. Al-
though there are some efforts that are starting to control
such carbon dioxide emissions based on UNFCCC, it is
not possible to fundamentally solve the energy depen-
dency of fos s i l fuels. Thus , s tudies on ne w a nd r enewable
energy have been largely conducted throughout t he world.
Wind power that is one of the new and renewable
energy has been considered as a subject in many re-
searches because it repr esents cle an energ y and low power
generation costs. Although the wind power has been de-
veloped based on large-scaled power generation systems
around the world, researches on small-scaled wind power
generation systems have been largely performed in recent
years. However, such small-scaled power generation sys-
tems show difficulties in starting a system and generatin g
power under the conditions of varying wind directions
and velocities at a low altitude because it applies a mi-
niature version of the large-scaled system.
In this study a simple wind tunnel is installed to de-
velop a small-scaled wind turbine generator as a vertical
axis drag type that shows efficient power generation un-
der the conditions of varying wind directions and veloci-
ties through introducing a simple wind tunnel. Then, the
mechanical and electrical power generated by a windmill
in a given wind speed are empirically measured to ana-
lyze the relationship between the mechanical and elec-
trical power.
2. Definition of Power
First, Wind flow can generate mechanical energy by ro-
tating a windmill with blades and the mechanical energy
can produce electrical energy through a generator. The
wind power generated by wind is presented as Equation
(1) where Pw is power (W), p is air density (kg/m3), A is
a projected area (m3), and V is wind speed (m/s).
Pw = pAV3/2 (1)
The mechanical power is defined by a mechanical pa-
rameter, Torque (T), and angular speed (w) as Equation
(2). Figure 1(a) shows an experimental configuration for
measuring its mechanical property.
Pm = T∙w (2)
The electrical power is defined by electrical parame-
ters, Voltage (V) and Current (I), as Equation (3). Figure
1(b) shows an experimental configuration for measuring
its electrical property [5 ].
Pe = V∙I (3)
3. Wind Tunnel Conditions
The output of the blower in the configured wind tunnel
presented in Figures 2 and 3 can be controlled with six
different steps and the wind speed can also be varied by
changing the steps. Table 1 shows th e averag e wind speed
in which the measurement is performed with a distance
of 3.5 m from the blower to the wind turbine generator.
4. Small-Scaled Wind Generator
The small-scaled wind turbine generator as a vertical axis