Abstract: A system for directing the ionized gases which can exit from the vent openings of the arc chambers in high power circuit breakers away from the line terminals of the circuit breaker and isolating these terminals from infiltration by such gases. The system includes a deflection plate, interphase barriers and end plates mounted in proximity to the vent openings and around the line terminals.

Abstract: A non-invasive system for accurately determining the counter EMF or speed voltages in an electric motor during motor operation. The system includes a mechanism for determining the phase angle of the stator current within the dq frame of reference and a mechanism for transforming feedback voltages into a new frame of reference defined by this phase angle. The speed voltage values thereby detected are free from stator resistance effects and represent parameters of improved accuracy which can be used in motor control functions.

Abstract: A processor module is one of several modules mounted in a rack to form a programmable controller. The module has a microprocessor that executes a sequence of machine language instructions to interpret and thereby execute macroinstructions that are part of a control program stored in a read/write volatile main memory. The rate of execution is improved by reducing the instructions in a fetch sequence used in coupling each macroinstruction to its interpreter sequence of machine-language instructions. Hardware assistance is provided to allow expansion of macroinstruction operation codes as they are fetched. The processor module also allows the user to program his own interpreter sequences for specially defined macroinstructions and to load these sequences into a nonvolatile memory that is plugged into the module. An external auxiliary power supply is connected to the processor module to supply the programming voltage required by the nonvolatile memory.

Abstract: A simple method and apparatus is disclosed for the calibration of a numerically controlled milling machine or the like, to determine the compliance for a particular set-up of the machine. The apparatus includes a hydraulic cylinder mounted on the machine bed, with the end of the hydraulic piston bearing against a non-rotating cutting tool that is mounted in the spindle. A pressure gauge or pressure switch indicates fluid pressure in the hydraulic cylinder to determine force of the piston on the cutting tool, and a deflection sensor measures the static deflection of the spindle. In one apparatus, hydraulic fluid from a high pressure source passes through a pressure-reducing valve into the rear of the hydraulic cylinder to push the piston rod end against the cutting tool, without requiring motion of the spindle relative to the bed, the valve being adjusted to maintain a desired fluid pressure behind the piston despite leakage of fluid past the piston.