Eaton Corporation

Richard J Kuntner

James C Vander Meer

James C Van Der Meer

A power interruption protection system for AC electric motors. An electroresponsive relay (OL) in the energizing circuit of an electroresponsive main power contactor (MC) for an AC motor is responsive to deliberately deenergize the contactor if a power supply interruption persists for more than a few cycles of the supply frequency. A motor current level detector (CLD) monitors the motor current and if it falls below a predetermined level activates a pulse counter (CTR) to register pulses from a clock pulse generator (CPG) which produces pulses each half cycle of the supply frequency. If the pulse counter registers a certain number or more of such pulses an amplifier-driver (AD) energizes the relay to effect disconnection of the motor from the AC supply. The system is disclosed both as a stand-alone system, and as combined in a system affording current overload protection modes as well for AC motors.

Power interruption protection system for electric motors

A solid state protection system for AC electric motors driving high inertia loads requiring long acceleration times. An electroresponsive relay (OL) is separately responsive to permissible acceleration time, circuitry (DT, DC), acceleration overload current circuitry (ACA), and to normal running overload current circuitry (ACR). Up-to-speed detector and latch circuits (USD, USL) deactivate the acceleration time circuitry and overload current circuitry, and activate the running overload current circuitry upon attainment of normal running speed by the motor. The response levels of the overload and time response circuits are individually settable.

Protection system for electric motors

A solid state motor control or power control universal assembly means and method whereby common parts are used to provide two basic semiconductor power pole versions, namely, a two-terminal power pole having two semiconductors in reverse-parallel connection between the terminals and a three-terminal power pole having two semiconductors in series connections between two terminals and a third terminal therebetween. These two power pole versions are the requiste subassemblies that may then be connected in various combinations to provide the numerous different types of motor control and power control systems commonly used. Each power pole consists of two semiconductors (either thyristors, diodes, or one of each) or the like, a combination of short and/or long bus bars (two short and one long bus bar for the 3-terminal power pole; two long bus bars for the 2-terminal power pole), one long and two short heat sinks, two clamps for clamping the power semiconductors between the bus bars and heat sinks, a support for mounting each power pole on a panel, control circuit mounted on the support, and lugs for connecting such systems to a power supply and motor or other load device. A plurality of these power poles may be mounted on a panel and connected as individual 2 and 3-terminal devices. Or a plurality of these power poles mounted on a panel also include bus connectors for connecting them into various power control configurations.

Growing community of inventors

Milwaukee, WI, United States of America

Richard J Kuntner