摘要:
A circuit controller for selectively connecting a power source to a load includes a switching mechanism, which selectively connects the power source to the load and switches a current which flows through the switching mechanism, and a substantially radiant energy dissipating positive temperature coefficient current limiter for limiting the current which flows through the switching mechanism. The switching mechanism includes a current sensor, which senses the current flowing through the switching mechanism and provides a sensed current value, and a switching controller for disconnecting the power source from the load whenever the sensed current value is above a predetermined current value. The switching mechanism may include a contactor having separable contacts which are responsive to the switching controller. The current limiter may have a first resistance which results from a first series current, and a higher second resistance which results from a second series current. The ratio of the second resistance to the first resistance may exceed 16. The current limiter may be a tungsten or, alternatively, a carbon conductor. The tungsten conductor dissipates greater than 70 percent of the energy of the short circuit current by radiation. The current limiter may further include a tubular glass cylinder which encloses the conductor therein. The cylinder may have two copper ends, each of which are electrically connected to a corresponding end of the conductor within the cylinder. The cylinder may further enclose a non-oxidizing gas, such as nitrogen, helium, argon, krypton or a halogen gas mixture. The conductor may be wound on a ceramic cylinder within the cylinder.
摘要:
Apparatus for monitoring power consumed from anywhere along the conductors in an ac power distribution system includes a housing with through passages through which the conductors extend. Toroidal coils mounted within the housing concentrically with the through passages sense the current in the conductors. Elongated electrically conductive screw fasteners threaded into support blocks mounted on a printed circuit board within the housing extend radially into the through passages to penetrate insulation on the conductors and to electrically contact and mechanically clamp the conductors thereby simultaneously providing a voltage tap and locking the housing to the conductor.
摘要:
A circuit controller for selectively connecting a power source to a load includes a non-overcurrent protective electrical switching mechanism and a conductive polymer current limiter connected in series with the load for limiting the current which flows through the switching mechanism whenever the power source is selectively connected to the load. The conductive polymer current limiter may include a plurality of parallel conductive polymer positive temperature coefficient (PTC) resistors. The circuit controller may include an electrical switching mechanism which, under short circuit conditions, remains selectively connected to the load. The short circuit current which is limited by the conductive polymer current limiter continues to flow through the electrical switching mechanism. The switching mechanism may include a contactor having separable contacts, and may further include a circuit interrupter, in order to provide a separate circuit disconnection mechanism. The electrical switching mechanism may have a coil and the circuit controller may include a voltage sensor. The conductive polymer current limiter may have an output which has a voltage substantially less than the voltage of the power source whenever the short circuit current flows from the power source and through the current limiter. The voltage sensor may be connected to the output of the conductive polymer current limiter and may deenergize the coil in order to open the separable contacts of the contactor and disconnect the power source from the load whenever the voltage of the output drops below a predetermined threshold. The contactor may be a motor-starting contactor.
摘要:
A contactor for selectively connecting at least one alternating current (AC) power line to a load and sourcing an AC current having periodic zero crossings includes a fixed contact; a movable contact mechanism; an operating mechanism for engaging and moving the movable contact to an open position in the absence of a closing signal; and a synchronized opening mechanism for disabling the closing signal in synchronization with a zero crossing of the AC current. The operating mechanism is disengaged from the movable contact, in a closed position, by a gap having a predetermined length in order that the contacts are separated at the AC current zero crossing. The contactor may further include a vacuum bottle for enclosing the fixed and movable contact therein. The movable contact may be carried within the vacuum bottle by a bottle stem which protrudes from the bottle and has a surface for engagement by the operating mechanism. The operating mechanism may include a crossbar and an arm having a surface for engaging and moving the bottle stem. The gap may be an overtravel gap between the arm and the bottle stem. The length of the gap may be determined by a length of the bottle stem or, alternatively, by a thickness of the contacts. The synchronized opening mechanism may include an electromagnet which has a coil which is energized in order to generate a closing current and which is deenergized in order to disable the closing current in synchronization with the zero crossing of the AC current. The length of the gap may be determined from a closing velocity of the arm multiplied by a period of the AC current zero crossings. The length of the gap may also be determined from a breakpoint in a plot of an overtravel gap versus contactor contact breaking cycle operations.
摘要:
A device for removing a coating formed in a slot of a stator core. The device includes a carriage movably attached to a first guide rail assembly to enable movement of the carriage in a longitudinal direction. The device also includes a first drive screw wherein rotation of the first drive screw moves the first guide rail assembly in the longitudinal direction. In addition, the device includes a second guide rail assembly that is attached to the carriage wherein the second guide rail assembly enables movement of the carriage in a direction transverse to the longitudinal direction. Further, the device includes a second drive screw wherein rotation of the second drive screw moves the carriage in the transverse direction. The carriage includes a laser beam emitting head that moves within the slot in either or both the longitudinal or transverse directions wherein the laser beam emitting head emits a laser beam to remove the coating.
摘要:
A remote-controlled dynamoelectric machine maintenance vehicle that can fit and travel within the air gap between a stator and rotor of a dynamoelectric machine. The maintenance vehicle has an effectuator that can remotely attach to an adjustable wedge within a coil slot of the stator and tighten the wedge in position and then move on to repeat the process until all the wedges on the stator are secured.
摘要:
A device for removing a coating formed in a slot of a stator core. The device includes a carriage movably attached to a first guide rail assembly to enable movement of the carriage in a longitudinal direction. The device also includes a first drive screw wherein rotation of the first drive screw moves the first guide rail assembly in the longitudinal direction. In addition, the device includes a second guide rail assembly that is attached to the carriage wherein the second guide rail assembly enables movement of the carriage in a direction transverse to the longitudinal direction. Further, the device includes a second drive screw wherein rotation of the second drive screw moves the carriage in the transverse direction. The carriage includes a laser beam emitting head that moves within the slot in either or both the longitudinal or transverse directions wherein the laser beam emitting head emits a laser beam to remove the coating.
摘要:
An inspection head where non-destructive inspection is structured to fit into narrow spaces, and to accurately and repeatably move an inspection probe along a surface to be inspected. Movement of the inspection head along an X, Y, Z, Θ, and Φ-axis is precisely controlled by individual drive mechanisms.
摘要:
A remote controlled inspection vehicle provides interchangeable modules, permitting the vehicle to be easily configured to perform a wide variety of tasks. The vehicle includes at least one frame module having a pair of drive modules on either side. Each drive module includes a continuous track surrounding a permanent magnet, and is dimensioned and configured to pivot around its longitudinal axis. The frame modules are dimensioned and configured to be hingedly secured to other frame modules, end effectors including various sensors for performing inspections, and tail units to assist in placing the vehicle in the desired environment.
摘要:
Camera system for viewing an object located in a region of contamination (e.g., oil, water, particulate matter, or the like). The system is capable of being internally pressurized above ambient pressure, so that the contamination is prevented from entering the camera system to foul the camera. The system includes a housing having an interior and a view port. An electronic sensor is disposed in the housing opposite the port for sensing the object and for generating an electrical output signal that travels along a conductor connected to the sensor. A processor is connected to the conductor for amplifying the output signal. The amplified signal is received by a display monitor which displays an image of the object. The system further includes a quick-disconnect connector which interconnects the housing to a source of pressurized fluid used to pressurize the housing above ambient pressure.