Teodor MILOŞ

THE INSERT OF METAL IN THE ROTOR BLADE OF

THE LOW POWER WIND TURBINE

Attachment of the wind turbine rotor blade is made by a metal structure, that provides a rigid mounting and precise positioning as accurate as possible to the calculated direction angle of incidence of the air flow relative to the blade profile sections. The mechanical strength at static load for the blade is within acceptable limits even without metal insert. In real operating conditions, the wind gusts have the effect of a dynamic load upon the blade and the base material, fiberglass reinforced polyester (FRP) is subjected to fatigue stressed. This leads to micro cracks in the resin and gradually reaches the blade breakage. Therefore the recessed fitting area of the blade, which is an aerodynamically inactive area, must have a metal structure with maximum adhesion to FRP of the blade structure. The shape of this structure, the way of insertion into the interior of the blade, the depth of penetration, are issues which will be discussed in this paper.

Keywords: insert of metal, blade, rotor, wind turbine, FRP

Cuvinte cheie: inserție metalică, paletă, rotor, turbină eoliană, PAFS

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DYNAMICS OF THE CENTRIFUGAL MECHANISM FOR
PROTECTION AT OVERSPEED OF THE LOW
POWER WIND ROTOR TURBINE
Rotor over speed protection for small wind turbine power requires a
mechanical system cheap and reliable as possible. This is because any electric
or electronic device depends on the electrical power source that disaster
becomes unavailable. Of these centrifugal mechanism is priced at acceptable
cost, but contains some subtleties of interpretation of the method of operation.
In this paper, we explain step by step the original solution of this mechanism
put in place for a 5 kW wind turbine.
After triggering centrifugal mechanism speed is reduced to 20 … 30
rev / min and the effect of centrifugal mechanism is greatly reduced. So that the
force of compressed spring plus aerodynamic torque blade in relation to spindle
axis, returns the mechanism to its original work position. For that to occur
slowly, return must be controlled by a hydraulic damper or a blockingunblocking
flag position for the rotor blades.
Adjusting ballast weight of centrifugal mechanism and the reliable
automatically operation of the whole system should be checked repetitively on
a trial endurance stand.
Keywords: wind turbine, force, torque, protection centrifugal
mechanism at over speed
Cuvinte cheie: turbină eoliană, forțe, momente, mecanism centrifugal,
protecţie la supraturare

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KINEMATICS OF THE CENTRIFUGAL MECHANISM FOR
PROTECTION AT OVERSPEED OF THE LOW POWER WIND
ROTOR TURBINE
Rotor over speed protection for small wind turbine power requires a cheap
and reliable mechanical system as possible. This is because any electric or
electronic device depends on the electrical power source that becomes
unavailable in disaster conditions. Of these, centrifugal mechanism is priced at
acceptable cost, but contains some subtleties of interpretation of the operation
mod. In terms of kinematics, centrifugal mechanism is reduced to a crank and
connecting-rod assembly with sliding piece. This paper presents schematically
this mechanism and the elements that govern the movement of the sliding
piece: race, speed and acceleration.
The mechanism function is alternative to a crank angle range of α =
0°…45°. Sliding piece is operated offset from the sliding axis. The complexity
consists in the fact that each blade is attached to the single sliding piece
through a rod and a crank. Thus the three rotor blades rotate simultaneously by
the cumulated action of the centrifugal force that occurs due to the rotating
counterweights.
Keywords: wind turbine, slide race, speed, acceleration, crank and
connecting-rod assembly
Cuvinte cheie: turbină eoliană, cursa culisei, viteza, accelerația, mecanism
bielă-manivelă

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PROTECTION CENTRIFUGAL MECHANISM OF
THE WIND TURBINE ROTOR AT OVERSPEED
The protection centrifugal mechanism at overspeed described in this paper is designed and made for a wind aggregate of 5 kW. This mechanism is a complex system, designed as an automatic mechanical system to react without electronic control. Only the returning to the initial state is controlled by the electronic system of automatic control of the wind turbine. The triggering of the centrifugal mechanism must be followed by the locking in its extreme position of the rotation of the blades. After locking, the speed is reduced to 20 … 30 rpm then, if weather conditions allow, it gives the command to unlock the centrifugal mechanism so the mechanism returns back to the normal working position.
Keywords: wind turbine, protection centrifugal mechanism at over speed, locking-unlocking device
Cuvinte cheie: turbină eoliană, mecanism de protecţie la supraturare, dispozitiv de blocare-deblocare

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STAND FOR TESTING THE OVERSPEED PROTECTION CENTRIFUGAL MECHANISM OF A 5 KW
WIND TURBINE ROTOR
The testing stand is designed to check the rotor protection complex system of a wind aggregate of 5 kW at over speed. The planned complex system is designed as an automatic mechanical system to react without electronic control. Only the returning to the initial state is controlled by the electronic system of automatic control of the wind turbine. The stand checks triggering centrifugal mechanism when is achieved the maximum rotation speed initially prescribed. The triggering of the centrifugal mechanism must be followed by the locking in its extreme position of the rotation of the blades. After locking, the centrifugal speed is reduced to 20 … 30 rpm then, if weather conditions allow, it gives the command to unlock the centrifugal mechanism. An electric motor drives a cam which raises the locking pin so that the centrifugal mechanism returns back to the normal working position. The adjusting of the centrifugal counterweight of the centrifugal mechanism and the impeccable operation of the whole automatic system should be checked on the testing stand. The purposes of the tests are to adjust, check and improve the endurance of the mechanism.
Keywords: wind turbine, testing stand, protection mechanism at overspeed, locking-unlocking device
Cuvinte cheie: turbină eoliană, stand de probă, mecanism de protecţie la supraturare, dispozitiv de blocare-deblocare

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