Patently Speaking highlights the technological achievements of Fort Wayne area residents.
Power stealing for a thermostat using a TRIAC with FET control
•U.S. Patent No. 7,755,220
•Invented by: Scott A. Sorg, Fort Wayne; Timothy N. Comerford, Indianapolis; and Donald R. Means, Indianapolis
•Assigned to: Carrier Corp., Farmington, Conn.
This patent sounds almost criminal. But it has nothing to do with stealing power from someone else. Rather, it’s a thermostat designed to draw small amounts of power from the devices it controls.
Newer thermostats control furnaces, blowers, motors and compressors. Relays and solid state switches enable the thermostat to effectively run a heating-cooling system based on temperature data it receives.
Conventionally, these thermostats are battery powered and supplemented by small amounts of current running through the wire connected to the motor or compressor the thermostat is controlling. Only small amounts of power are drawn so the device is inadvertently turned on. This is “power stealing.” Nevertheless, these thermostats still drain a lot of battery.
This patent describes a new thermostat circuitry that improves power stealing capabilities and lessens battery drain. The circuit includes an amplifier with an input for controlling the state of the amplifier, as well as an output for generating a direct current control signal. The amplifier input is electrically coupled to an isolated gate field-effect transistor to assist controlling the state of the amplifier. Power stealing supplies the power to the field-effect transistor, resulting in less battery drain.
Slow-speed direct-drive generator
•U.S. Patent No. 7,750,522
•Invented by: David M. Erdman, Fort Wayne; Joseph E. Miller, Fort Wayne; Daniel Gizaw, Belleville, Mich.; and Girma Desta, Suwanee, Ga.
•Assigned to: Danotek Motion Technologies, Ann Arbor, Mich.
Brushless-permanent magnet motors are common for small devices that operate at high speed. These motors are typically not used in slow-speed applications because of the size of the magnets inside them that cause cogging torque. This is problematic with slow-speed operations because cogging torque creates jerkiness in the motor.
An application where these motors can be useful is with those large power-generating windmills. A gearbox converts the slow turn of the blades into a faster moving generator.
This patent describes a new motor specifically used at slow speed for windmills without not suffering from cogging torque. This motor includes several magnets lining the inside surface of a rotor mount in such a way as to create alternating polarity to stagger magnetic skew. Cogging torques are still created. In fact, two cogging torques are created. But these torques act in opposite directions from each other. This has the effect of canceling the torques out, eliminating the jerkiness.
The preceding are lay descriptions of patents obtained from the United States Patent and Trademark Office’s public records and are provided for general information purposes only. Nothing contained herein is a legal description of any claimed invention, identification of novelty, or offer of legal advice. Because issued patents are based on applications often filed years earlier, the subject matter of some patents may have been available on the market for some time prior to the issuance of the patent. Additional information on these patents is available at www.uspto.gov.
