Eaton Corporation

Drs Power & Control Technologies, Inc.

James C Vander Meer

Richard J Kuntner

Peter K Moldovan

Ashish R Bendre

Slobodan Krstic

Robert M Cuzner

Hemant K Mody

Robert W Spink

Craig Goshaw

A four pole, three-phase, NPC converter that produces virtually no common mode voltage. The low common mode voltage output is achieved by constraining the switch states of the NPC converter. A fourth pole and associated control balance the upper and lower DC link voltages. The converter may be an inverter or a rectifier.

Four pole neutral-point clamped three phase converter with low common mode voltage output

An electric arc extinguishing mechanism is provided for an electric current switching apparatus of the type having a pair of contacts which selectively engage to complete an electric circuit. The mechanism includes a plurality of splitter plates located adjacent to the contacts and formed of electrically conductive material. Each splitter plate has a body of electrically conductive material, and a casing with a pair of planar portions on opposite sides of the body and connected by the curved edge portion. The edge portion is adjacent the contacts with the planar portions extending from the edge portion in an open loop having a gap. Any arc introduced between adjacent splitter plates moves around the open loop before being extinguished thereby not residing in one spot long enough to cause gross melting and associated erosion of the splitter plate.

Electric current switching apparatus with arc spinning extinguisher

A three-phase motor control system (FIG. 1) having a current control regulator (CCR) that includes adjustable current ramp time or adjustable current level during starting and acceleration and incorporates a load voltage-current displacement regulator (VCFB) that automatically becomes effective when the motor approaches synchronous speed, thereby to reduce the power input to the motor to what is needed to run the load, thus saving energy. Additionally, a second quadrant detector (SQD) senses overhauling load conditions and operates a gate (NG) to lock out the load voltage-current displacement feedback signal thereby allowing the reference signal to place the motor across the line until the motor operation returns to the motoring quadrant. The system further includes means (24 in FIG. 2h) affording integral control and means (30 in FIG. 2h) affording proportional control of either the current control or the load voltage-current displacement control signal, with the gain of the proportional control being individually adjustable. The integral control is provided with high gain means (FET in FIG. 2h) that is rendered effective by a switch (TR in FIG. 2h) during current control and alternative low gain means (P4 in FIG. 2h) that is substituted during load voltage-current displacement control, the gain of the latter being individually adjustable.

Load voltage-current displacement regulator motor control system

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.

Growing community of inventors

Brookfield, WI, United States of America

James C Vander Meer