Abstract: This invention discloses an electronic control system for an Industrial Motor Operator that uses standard steady state logic to improve reliability in rough service wet and dirty environments. It includes means of providing electronic snow limit to close limit sensing removing the need for two switches and radically improving its accuracy. A low voltage switch reverses the high voltage motor wires and at the same time reverses the open limit, close limit, and snow limit sensors mechanical positions. It discloses a system using lamps to indicate that the power wiring is connecting to three-phase motors in the correct sequence or that single-phase motors have their windings correctly phased.

Abstract: A one wire interface for optical emitter-detectors is disclosed that is fail-safe, simple, and includes diagnostics, noise and static protection. Two indicator lamps are used for diagnostics indicating four conditions; a) Ready, b) Not Connected, c) Blocked Beam, d) No power. This allows single or two conductor systems to have the same troubleshooting information as the 4-wire systems.

Abstract: A simple non-moving passive electric probe detects the height of a solution along its surface. Liquid resistance and thin water films are disregarded and setting of the liquid level is accomplished electronically without moving the probe. An output signal proportional to the height of a solution along the probe length is provided. Means are disclosed electrically pierce though oil films, soap foams or grease layers that can coat a probe, preventing contact with the solution. The system will sense distilled water, city water, sewage, wine, milk, soda, juice, alcohol, latex paint or any other water based solutions.

Abstract: A method and apparatus for controlling refrigerant gas pressure in a low pressure refrigeration system including a warm surface within a container. Liquid refrigerant is removed from the refrigeration system evaporator and sprayed on the warm surface, thereby vaporizing. The resulting pressure differential between the container and the evaporator causes the vaporized refrigerant to be returned to the evaporator through an open return line. The warm, surface is downwardly concave so that non-volatile liquid which had been mixed with the refrigerant can be collected from the bottom of the surface and transported to a location remote from the evaporator, thereby separating contaminants from refrigerant.

Abstract: A variable speed control system for a single phase AC induction motor wherein a controllable switch is in series with the main winding of the motor, while the auxiliary winding of the motor, which is in series with a capacitor, is continuously energized. The switch is opened whenever the current through the main winding passes through zero. While the switch is open, the back e.m.f. in the main winding is sensed to provide a measure of the speed of the motor. This is compared with a desired speed signal and the comparison is utilized to control closure of the switch. The speed of the motor then remains constant at the desired speed, even with a varying load.

Abstract: A method and apparatus for electronically pressure sealing and leak testing an idle centrifugal chiller system wherein a small positive differential is maintained between the internal refrigerant vessel pressure of the chiller system and the ambient atmosphere. This differential pressure is maintained by selectively applying heat to the refrigerant.

Abstract: A method and apparatus for controlling refrigerant gas pressure in a low pressure refrigeration system including a warm surface within a container. Liquid refrigerant is removed from the refrigeration system evaporator and sprayed on the warm surface, thereby vaporizing. The resulting pressure differential between the container and the evaporator causes the vaporized refrigerant to be returned to the evaporator through an open return line. The warm, surface is downwardly concave so that non-volatile liquid which had been mixed with the refrigerant can be collected from the bottom of the surface and transported to a location remote from the evaporator, thereby separating contaminants from refrigerant.