Patent application number | Description | Published |
20090167256 | System and method for suppressing DC link voltage buildup due to generator armature reaction - A controller employed in conjunction with a synchronous generator monitors the output voltage of the generator. The controller employs the monitored output voltage as feedback that is used to control the excitation provided to an exciter field winding. In addition, the controller applies a control loop to the monitored output voltage that detects and modifies voltage ripple signals within the monitored output voltage to generate a compensated signal that is used to control the excitation to the exciter field winding. In particular, by detecting and modifying voltage ripple signals within the monitored output voltage, the controller is able to counteract armature reaction voltage ripples caused by unbalanced short-circuit faults, thereby preventing the build-up of voltage on the DC link. | 07-02-2009 |
20120182648 | OVERVOLTAGE LIMITER IN AN AIRCRAFT ELECTRICAL POWER GENERATION SYSTEM - A generator includes a permanent magnet generator, an exciter and a main generator mounted for rotation on a shaft. The main generator is configured to produce a voltage output. A generator control unit includes a circuit configured to provide current from the permanent magnet generator to the exciter. A switch is provided in the circuit and is configured to change between open and closed conditions. The switch is configured to flow current in the circuit in the closed condition and interrupt current flow in the open condition. An overvoltage limit controller is programmed to determine an amount of overvoltage of the output voltage exceeding a desired voltage. Either a fixed reference threshold is used or a reference threshold voltage is calculated based upon the duration in over voltage condition, and the switch is modulated between the open and closed conditions according to error between the actual output voltage and the reference threshold voltage to limit the output voltage to the desired reference threshold voltage. | 07-19-2012 |
20130003231 | OVERVOLTAGE PREVENTION IN AN AIRCRAFT ELECTRICAL POWER GENERATION SYSTEM - An example method of detecting a generator overvoltage condition includes predicting a primary control current to provide a predicted control current, monitoring the primary control current, and detecting a generator overvoltage condition based on a comparison of the predicted control current to the primary control current. The method interrupts the primary control current based on the comparing. | 01-03-2013 |
Patent application number | Description | Published |
20120234506 | LIGHT BLOCKING SLATTED BLIND - A slatted blind is configured such that the slats close create a light blocking blind. The slats may be supported by a tilt cord that comprises a low stretch strand or a low stretch cord may be attached to the tilt cord. The slats may be connected to the supporting tilt cord such that when the slat is rotated to a closed position the slat is suspended from the rung. The rung may have an effective diameter of less than approximately 14 mil. Recesses may be formed in the slat for receiving the rung when the slat is in a closed position. A bottom rail may have a thickness approximately equal to the thickness of the slats. A protrusion may be formed on the back of the slats such that the rung pushes on the protrusion to force the slat against an adjacent slat when the blind is closed. | 09-20-2012 |
20140014279 | WINDOW COVERING AND OPERATING SYSTEM - A window covering includes a head rail that supports a panel by lift cords such that one end of the panel may be raised and lowered relative to the head rail. An operating system controls movement of the panel and includes spools coupled to the lift cords such that rotation of the spools retracts and extends the lift cords. A shaft is connected to a spool of the lift spool assembly and to a brake and a spring motor. The spring motor applies a motor force to the shaft and the brake applies a brake force to the shaft such that the forces generated by the spring motor and brake hold the panel in the desired position. | 01-16-2014 |
20140360683 | SEALED SLATTED BLIND - A window covering comprises slats suspended from a tilt cord such that the tilt cord may rotate the slats between an open position and a closed position. An elastic seal is provided on the slats to contact adjacent slats when the slats are in the closed position. A mechanism such as a spring or a magnet applies a closing force to the slats in the closed position separate from the tilt cord where the closing force moves the slats toward one another. An elastic seal is provided on the slats to contact adjacent slats when the slats are in the closed position. | 12-11-2014 |
20150028144 | VARIABLE FORCE BRAKE FOR A WINDOW COVERING OPERATING SYSTEM - An operating system for a window covering includes at least one spring motor, at least one variable force brake, and at least one lift spool assembly operatively coupled to a panel for raising and lowering a panel. An effective shaft is operatively coupled to and synchronizes the spring motor, the variable force brake, and the lift spool. The variable force brake comprises a one-way clutch operatively coupled to the shaft. A brake member is operatively engaged with the one-way clutch to apply a brake force to the one-way clutch when the shaft is rotated. The magnitude of the brake force applied to the one-way clutch is determined by the rotational position of the shaft. | 01-29-2015 |