Abstract: Detection of a locked rotor condition of an electric motor during startup herein uses a virtual speed switch. The methods and systems herein determine whether the motor is in a starting state, and the monitor the motor current to determine if it is greater than a predetermined threshold, and that the motor current decrease exceeds a predetermined threshold after a predetermined amount of time. If the decrease in motor current is not less than a predetermined threshold, then a speed switch bit is set, indicating that the rotor is turning. The methods and systems herein further determine whether a physical speed switch is faulty, and determine a locked rotor condition using the virtual speed switch signal, a physical speed switch signal, and whether the physical speed switch is faulty.

Abstract: Detection of a locked rotor condition of an electric motor during startup herein uses a virtual speed switch. The methods and systems herein determine whether the motor is in a starting state, and the monitor the motor current to determine if it is greater than a predetermined threshold, and that the motor current decrease exceeds a predetermined threshold after a predetermined amount of time. If the decrease in motor current is not less than a predetermined threshold, then a speed switch bit is set, indicating that the rotor is turning. The methods and systems herein further determine whether a physical speed switch is faulty, and determine a locked rotor condition using the virtual speed switch signal, a physical speed switch signal, and whether the physical speed switch is faulty.

Abstract: An improved reactance characteristic for an overall ground distance quadrilateral characteristic embodies a particular phase selector, possibly among a plurality of phase selectors and variables, that eliminates undesirable generation of a tripping signal other than only for a selected phase to ground fault. This phase selector is I1FZ1, where Z1 is the positive sequence replica impedance and I1F is the fault component of the positive sequence current component, referenced to the proper phase. Preferably, the pre-fault load current is removed from this quantity. Additionally, an improved restricted phase directional function is implemented, further improving the overall performance of the quadrilateral characteristic relay.

Abstract: A protective relay for detecting faults within a predetermined protected zone of a three phase alternating current electrical power distribution system, of the type which utilizes at least one restraint signal in conjunction with at least one operate signal to generate a net operate signal, generates an operate quantity which is related to a zero sequence component of current flowing in the power distribution system and a second operate quantity which is related to a negative sequence component of the current flowing in the power distribution system. The operate quantities are summed to form an operate signal. An adaptive restraint, which is proportional to a negative sequence component and a zero sequence component of a phase voltage of the power distribution system, is generated and utilized to provide increased sensitivity to higher resistance ground faults.

Abstract: A device for repairing windshield cracks. A cylinder includes a sealing mouth adapted to contain a quantity of filler material. The mouth with filler material therein is positioned over the crack opening. The cylinder includes a small cavity adjacent the mouth and a larger upper cavity. A plunger fitted to the cylinder carries a lower seal for the small cavity and an upper seal for the larger cavity. Moving the plunger from an initial fully depressed to a fully retracted position opens the small cavity to the upper cavity whereby the vacuum of the upper cavity enhances the evacuation of air from the crack. Subsequent depression of the plunger is assisted by a one-way exhaust valve. Such depression of the plunger produces injection of the filler material into the crack replacing the evacuated air.

Abstract: This invention is directed to an apparatus and method for repairing pock marks and bullseyes in glass such as a windshield and such as plate glass. The apparatus comprises essentially an adapter, a syringe and a polymerizable resin. The adapter is attached to the glass over the pock mark or bullseye. The syringe with the polymerizable resin is positioned in the adapter and the polymerizable resin forced into the pock mark or bullseye.

Abstract: A phase comparison type ground distance relay for a predetermined phase of three-phase AC transmission line includes a phase coincidence detector responsive to phase coincidence between an operating signal and a plurality of polarizing signals. Zero suppression networks are utilized for deriving second and third polarizing signals in order to improve discrimination between internal and external faults; thereby increasing the reliability of the relay operation and the security of the protection system. The second polarizing signal comprises that portion of a signal which exceeds a predetermined threshold value and which is related to the product of a signal proportional to the net current flowing in all three phases of the power system and the positive sequence replica impedence of the transmission line.

Abstract: An air diffuser includes first and second walls disposed in spaced side-by-side relationship and cooperating to define a passage for the flow of air in one direction between said walls. A pair of flanges extend towards each other from the downstream edges of the walls and defining an elongated outlet slot narrower than the width of said passage. A deflector vane is narrower than the passage and is disposed in the passage in a plane spaced upstream from the slot and generally parallel to said flanges. The deflector vane includes an inverted U-shaped central channel and flanges extending away from each other from the down stream ends of the U-shaped chanel and arranged generally parallel to the flanges defining the slot. The opposite ends of the vane are engaged in a U-shaped support with a spring engaging one wall of the U-shaped support and biasing the vane flanges into sliding engagement with the other wall.

Abstract: A phase relay utilizes improved polarizing and operating signals in order to provide discrimination between internal faults within a protected zone of an AC power transmission line and external faults than can appear as internal faults due to transients induced by capacitive voltage transformers or series capacitors. A zero sequence restraint signal is used to block operation of the phase relay on close-in single line to ground faults. A filter is used in a by-pass circuit to attenuate high frequency transients which might delay, and possibly prevent a trip output on an internal fault. A high set by-pass circuit, including zero suppression to preclude an output on an external fault, is employed to provide faster operating times on severe internal faults. Forward offset and/or zero suppression of the polarizing signal is used to reduce the characteristic timer setting and therefore increase the speed of the phase relay operation.