Communications: electrical – Systems – Selsyn type
Reexamination Certificate
1997-05-28
2001-01-30
Crosland, Donnie L. (Department: 2736)
Communications: electrical
Systems
Selsyn type
C340S870300, C340S870330, C340S595000, C340S671000, C340S672000, C340S686300, C341S192000, C219S483000, C244S13400A, C310S114000, C416S095000
Reexamination Certificate
active
06181235
ABSTRACT:
TECHNICAL FIELD
This invention relates to rotary apparatus incorporating electrically powered devices and a method and means for controlling the supply of power to said devices. In particular, the invention relates to propellers incorporating a de-icing system.
Aircraft propeller de-icing systems comprise heating devices mounted on the leading edges of propeller blades and switching means to control the application of power to these heating devices so that they are energised periodically to melt the boundary layer of ice and allow the remaining ice to break free under the effect of centrifugal and aerodynamic forces. Continuous operation of the heating devices is not desirable because this causes continuous melting of ice, which runs back onto the blade and re-freezes on aerodynamically critical working surfaces.
It is known to incorporate a permanent magnet electrical generator in the propeller hub so that rotation of the propeller generates the power supplied to the heating devices on the blades.
In GB2264812, we proposed a propeller de-icing system including a permanent magnet electrical generator in the hub to supply power to a switching circuit rotating with the hub and which includes a distributor switch and the heating devices and the distributor switch is controlled by a timer on the hub, which is controlled in turn by a control signal supplied to it via a rotary connection from the aircraft on which the propeller is mounted.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide an improved propeller de-icing system; in particular, a system which avoids electrical contacts between the propeller and the airframe on which it is mounted, and which allows operation of the heating devices to be monitored and controlled accordingly.
According to the present invention, power is switched to one or more electrically powered devices on a rotor by providing switching means on the rotor responsive to a control signal to supply power to said devices, and said control signal is supplied to the switching means via a contactless communication link between the rotor and structure on which the rotor is rotatably mounted.
Preferably, the rotor incorporates an electrical generator with inductive windings in which power is generated by rotary motion of the rotor, and the communication link comprises an inductive link incorporated in the generator. For example, with a permanent magnet electrical generator, windings may be provided on the rotor to generate an induced voltage when rotating relative to fixed magnets, and these same windings, or separate windings, may then be used as said inductive communication link by further inducing a modulated voltage or current using a control signal in a winding on the magnets.
The control signal is preferably an encoded binary signal and the switching means includes decoding means to decode the control signal. In this way, control signals can be addressed to individual switching means, each controlling operation of a separate device. For example, in the case of a propeller de-icing system, the heating devices on different blades can be separately controlled.
Additionally, the same communication link or a similar link may be used to transmit performance information from the rotor to a controller, and the controller may be adapted to respond to said performance information by transmitting appropriate control signals to the switching means. For example, in the case of a propeller de-icing system, the current and voltage in individual heating devices may be monitored and appropriate information transmitted to a de-icing controller.
In an alternative embodiment of the invention, the contactless communication link between the rotor and the structure on which it is mounted comprises a radio frequency link or an optical communication link.
REFERENCES:
patent: 4292502 (1981-09-01), Adams
patent: 5144299 (1992-09-01), Smith
patent: 5558495 (1996-09-01), Parker et al.
patent: 5793137 (1998-08-01), Smith
patent: 0530612 (1993-03-01), None
patent: 2281273 (1976-03-01), None
patent: 2671650 (1992-07-01), None
patent: 2264812 (1993-09-01), None
Baker & Botts L.L.P.
Crosland Donnie L.
Ultra Electronics Limited
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