A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. Also called a rotary electrical joint, collector or electric swivel, a slip ring can be applied in any electromechanical system that requires unrestrained, intermittent or continuous rotation while transmitting power and / or data. Moreover, it can improve mechanical performance, simplify system operation and eliminate damage-prone wires dangling from movable joints.
First, core function: realizing continuous transmission for electric power and the signal
In the process of wind power generator set's operation, cabin needs to 360-degree continuous rotation (yaw maneuver) according to wind directions. Meanwhile, its blade rotates around its axis controlled by its pitch system for the purpose of maximum capturing wind power. However, if the cable, as its electric supply for the motor, control system and its sensors, is directly connected, it will be twisted off during its rotating operation, leading to system inefficiency.
Slip Ring smartly solves that puzzle with its rotating components (rotor) and stationary components (stator).
- Rotor: rotating along with the cabin or the hub which connects with the motor, pitch motor and the sensor.
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Stator: fixing on its tower cylinder for connecting external power grid and its main control system.
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The above-mentioned two parts can realize in-time transmission of its current and signal through sliding connection between precise conductive ring and flexible brush.
Therefore, slip ring has three key missions:
- Electric power transmission: stable output generated by the motor (400V dynamic electricity) from rotating cabin to fixed cable.
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Control signal transmission: including pitch order and yaw control signal for the purpose of ensuring optimized windward angle of the blade all the time
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Data communication: in-time feedback supervision data, including wind speed, wind directions, its vibration and the temperature, smart control support and fault early warning
Second, core function: ensuring high system efficiency with stable operation
Slip Ring serves as not only a physical connection component but also an important effect on overall performances of wind power system. Refer to the followings:
- Ensuring system consecutiveness and stability
Slip Ring functions as continuous operation of "no power failure and no signal interruption". Whatever the cabin rotates, its electric power and signals will smoothly transmit for the purpose of ensuring continuous power generation and in-time control, laying a solid foundation for continuous running within 365-day operation.
2. Imporving generating efficiency
Precise pitch and yaw control depend on high-quality signal transmission of Slip Ring. Once signal delay or lost, blade angle may cause its deviation, reducing capture efficiency of its wind power. High-performance slip ring can effectively reduce signal attenuation and interference, improving operation conditions for its fan at the best level.
3. Strengthen system reliability and safety
Modern slip ring adopts superior conductive material (copper alloy and precious metal coating), self-lubrication brush and multiple leak-proof structures (above IP65 prevention level) for the purpose of wind-and-sand prevention, high-and-low temperature resistances (-30℃ to +70℃), humid-resistance and corrosion proof, adopting long-period running with extreme environments such as Inner Mongolia and East-North areas and reducing failure risks caused by operation environments.
4. Reducing maintenance costs and prolonging lifetime
Traditional cable wrapping plan needs to frequent maintenance even replacement. However, its design lifetime of high-quality slip ring can reach 20 years or billions of times rotating, namely maintenance-free or lower maintenance, for the purpose of remarkable reduction of breakdown time and maintenance costs. What's more, modular design supports quick replacement for the purpose of improving overall economy of wind plant.
5. Supporting smart and digital upgrading
With the development of "smart" wind power, slip ring severs as not only transmit basic power and switch signal but also support the mission of high-speed data communication. Support Internet, CAN Bus and optical-fiber-composite-transmission "smart slip ring" popularization for the purpose of integrating temperature sensor and vibration supervision module, of realizing state perception and predictive maintenance and of laying a solid foundation for digital wind power construction.
