Abstract: The present invention is directed to an inductively driven electromagnetic linear actuator arrangement employing eddy currents induced by a fixed drive coil to drive its armature. Eddy current focusing fields are employed to direct the eddy currents using Lorentz forces to maximize armature speed. The armature includes a shorted driven coil in a DC magnetic field. This can be supplied by a permanent magnet. When current is applied, a force is felt by the coil in a direction perpendicular to the magnetic field. Such an actuator is well suited for electrical switching applications including transfer switching applications, circuit breaker applications, and ground fault interrupter applications.
Abstract: The present invention is directed to an inductively driven electromagnetic linear actuator arrangement employing eddy currents induced in an armature by a drive coil to drive the armature. Eddy current focusing fields (Lorentz force) are employed to direct the induced eddy currents to maximize armature speed. The armature includes a shorted driven coil in a DC magnetic field that focuses eddy currents induced by the drive coil in the driven coil. The DC magnetic field can be supplied by one or more permanent magnets. When current is applied to the drive coil, a force is felt by the driven coil in a direction perpendicular to the magnetic field, causing armature movement. Such an actuator is well suited for electrical switching applications including transfer switching applications, circuit breaker applications, and ground fault interrupter applications.
Abstract: Methods and apparatus for eliminating the effects of electrosurgical interference on continuous, heat-based cardiac output measurements employing several procedures, including the steps of (1) supplying power via an isolation transformer and carrier frequency to a catheter-mounted heating element; (2) measuring the voltage and current on the primary side of the isolation transformer; (3) determining the voltage and current on the secondary side of the transformer on the basis of the measured primary side voltage and current; and (4) calculating the power delivered to and resistance of the catheter-mounted heater on the basis of the secondary voltage and current. A heater power waveform generated with this process will be substantially free of electrical interference due to electrosurgical devices. Then, a system transfer function may be produced via signal processing techniques which involve cross-correlating the heater power waveform with the blood temperature waveform.
Type:
Grant
Filed:
February 7, 1992
Date of Patent:
April 26, 1994
Assignee:
Interflo Medical Inc.
Inventors:
Russell C. McKown, Chris Eckert, Michael D. Quinn