New pulse encoder increases security in wind turbines
The Swedish encoder manufacture Leine & Linde is launching a new series of pulse encoders developed for applications that require highly functional security. The new pulse encoders will make it easier for equipment manufacturers to meet the new rules which come into force on 29 December 2009.
“Our new 800 series offers solutions for security critical applications, for example through a sinusoidal output signal combined with a keyway shaft,” explains Joel Zachrisson, Product Manager at Leine & Linde. “The design means that these pulse encoders are suitable for applications where extensive damage to equipment can occur if the signal from the pulse encoder fails. One such example can be found in the wind power industry. If the generator speed feedback fails in a wind turbine, this could cause the turbine to fly off. Our new pulse encoder contributes to greater security in this type of application.”
Keyway – no risk of the shaft slipping
The new pulse encoder differentiates itself from standard pulse encoders in the area of the electrical and mechanical interface. The encoder's hollow shaft can now be equipped with a keyway to prevent the shaft slipping against the application's shaft. “This solution ensures that the encoder's shaft turns continuously, even if oil and debris find their way in or if the encoder is not mounted 100% correctly,” continues Joel Zachrisson.
Reliable electronics with analogue interface
Analogue electronics with a so-called 1 Vpp interface have been used to further increase operational security. 1 Vpp means that the electrical signals from the encoder are sinusoidal with an amplitude level of 1 volt. “1 Vpp is safer than square signals, since the analogue signal has a unique value in each position. Extremely small changes in position of the encoder shaft are directly perceived by the system which interprets the signals from the pulse encoder. In contrast to a pulse encoder with a traditional square pulse there is no state in the analogue 1 Vpp signal that could be interpreted as permissible, even if the basic electronics are defective. Pulse encoders with analogue 1 Vpp electronics are important for the customers who want to have secure control of their equipment,” concludes Joel Zachrisson.