Fail-safe electric actuator using high voltage capacitors
AssigneeSiemens Building Technologies, Inc.
InventorsDonald E. Charles, Matthew D. Cook
Life of this patent
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Abstract
According to the present invention, a fail-safe circuit for controlling an actuator is provided with an input voltage which is rectified and converted to a DC voltage. The DC voltage is boosted to a high level, and high voltage storage capacitors are charged at this high voltage level resulting in smaller, less expensive capacitors. The high voltage from the storage capacitors is then converted back to a smaller DC voltage to drive the motor of the actuator. Reduced size and increased energy storage is based on the relationship between capacitance and voltage in the equation: E=½ CV2.
Claims12
A method of returning a device to a safe position using a motor in the event of a power failure, comprising:
- providing an input voltage signal;
- boosting said input signal to a higher voltage and applying said boosted signal to a plurality of storage capacitors to provide a stored voltage signal;
- converting the stored voltage signal into a smaller voltage signal, and
- applying the smaller voltage signal to said motor when a low voltage signal is detected, said motor returning said device to a predetermined safe position.
An electronic device comprising:
- a voltage input circuit, said voltage input circuit responsive to an voltage input signal;
- a booster circuit for converting said voltage input signal into a larger voltage signal;
- a capacitor storage bank including at least one capacitor for storing said larger voltage signal as a stored voltage signal;
- and
- a flyback circuit for converting said stored voltage signal into a smaller voltage signal to be applied to an actuator in the event of a power failure, said actuator returning a device to a predetermined safe position.
Dependencies are inferred from the claim text.