Abstract: A system for controlling current flow to the actuating coil of a contactor or the like. A solid state switch is provided for gating current flow to the coil, and operated by an oscillator stage. A time delay causes the oscillator to operate at a high duty cycle when power is initially applied, allowing a relatively high current to flow to the contactor coil to operate the contacts. Subsequently the control causes the oscillator to operate at a low duty cycle, wherein the solid state switch passes a significantly lower current flow to the coil to maintain the contacts in position.

Abstract: The invention relates to an axial fan with blades that automatically adjust to the direction of rotation. The fan blades are mounted with freedom to swivel on the fan wheel and are limited in their swiveling motion by stops which are provided on the fan wheel. In order to reduce the manufacturing cost of such an axial fan, spokes, to which the fan blades are fastened by means of film hinges are mounted on the fan wheel. The fan wheel is made from a single piece of plastic.

Abstract: A contactor having main and auxiliary contacts and an arc quenching system including a blowout coil. The blowout coil is connected in series with a first and second set of auxiliary contacts and the resulting series combination connected in shunt around the main contacts. The second set of auxiliary contacts is arranged to open after the first auxiliary closes and before the main contacts close in order to remove the blowout coil from the circuit when the main contacts are carrying load current.

Abstract: An operator is provided for a molded-case circuit breaker of the type in a motor controller where the circuit breaker is removably mounted on a pan brace which is held in place by a pan latch. The operator mounts on the breaker for opening and closing the breaker and for providing three interlocks. One interlock prevents withdrawal or insertion of the breaker with the operator handle in the "on" position. A second interlock prohibits closing or opening the control door except when the handle is off and a third interlock locks the operator handle in "off" position.

Abstract: A so-called blow-off type current limiting circuit breaker includes a stationary contact strap that is divided into three elongated closely spaced coplanar parallel arms that are connected to each other at one end of the strap. The stationary contact is mounted to the interior one of the parallel arms at the end thereof remote from the one end of the strap. A terminal portion of the strap connects exterior ones of the parallel arms to one another at the ends thereof remote from the one end of the strap. A movable contact engageable with and disengageable from the stationary contact is mounted to one end of a movable contact arm that is pivoted at its opposite end in the region of the one end of the strap, extending parallel to the arms of the strap and being aligned with the interior arm. Current in the interior arm flows in a direction opposite to the direction of current flow in the exterior arms and the movable contact arm.

Abstract: A device for determining a load operating parameter signal, such as the flux of a rotary field machine, has an integrating circuit added at the input of the instrument transformer with a transfer function k/(1+s.multidot.k/.omega..sub.N) that amplifies reduced low frequency load voltage inputs to the transformer to avoid calculation inaccuracies due to the transformer transfer error. Circuitry having the inverse transfer function located at the output of the transformer compensates for the amplification distortion.

Abstract: A flow control valve, especially for use in controlling the operation of a steam turbine, includes a valve seat arranged in the interior of a valve housing, and a diffusor arranged downstream of the valve seat, as well as a valve member which is mounted in a valve member guide toward and away from the valve seat to accordingly throttle the flow of steam or a similar medium through the interior of the valve housing and into the diffusing channel of the diffusor. Minimization of alternating forces tending to excite the valve member into oscillating and stabilization of the flow of the medium in the channel disposed downstream of the valve seat are achieved by the provision of internal ribs within such a channel. At least three such ribs are provided, projecting at least substantially in the respective radial directions or parallel thereto from the surface bounding such channel.

Abstract: A three-position electrical driving mechanism having a jump-drive sub-assembly, a pivotable actuator and associated spring arrangement for storing energy, a detent arrangement and associated latches for holding the detents in place, a release arrangement for disengaging the detents from the latches, and a storage drive sub-assembly which is operable in response to a blown fuse or an open circuit trip. This switch requires the operator to perform the same switching operation each time the switch is utilized, and therefore errors that occur when an operator must perform several different operations are avoided.

Abstract: In the method according to the invention, Cr powder is poured into a degased mold, which can be made of graphite. On this Cr powder a piece of low-oxygen copper is placed. Subsequently, the mold is closed with a porous cover, which can also be made of graphite. Then the mold is degased in a high-vacuum furnace at room temperature until a pressure of better than 10.sup.-4 mb is reached. Thereafter, the furnace temperature is increased to as high as possible a temperature below the melting point of copper. This furnace temperature is maintained constant until an internal pressure in the furnace of better than 10.sup.-4 mb is reached. Subsequently, without intermediate cooling, the furnace temperature is further increased slowly to a final value of 100 degrees K. to 200 degrees K. above the melting temperature of the copper. This temperature is then maintained until the porosity contained in the Cr powder is completely filled up by the liquid copper.

Abstract: A one-piece, slam-type latch for snap-in installation in an orifice of a door is provided for maintaining the door in a closed position relative to a door frame having an extending keeper means. The latch includes a first portion having a generally rectangular configuration, and a second portion extending normally outward from the first portion for insertion through the orifice. One end of the second portion is in integral attachment with one side of the first portion. The other end of the second portion is provided with at least one indentation for interlocking engagement with the keeper means. A leaf spring is integrally attached to the second portion and extends angularly from the second portion toward the first portion. The latch is further provided with a third portion in integral engagement with the first and second portions. The third portion extends planarly outward from the first portion.

Abstract: A so-called blow-off type current limiting circuit breaker is constructed with a contact pressure spring that also holds the contact arm in open contact position when the contacts are blown open by electrodynamic forces. A multi-section cam means transmits contact opening and closing forces produced by a spring powered overcenter toggle type operating mechanism to the movable contact arm. A follower on the latter is biased into engagement with the cam means by the contact pressure spring. The cam means is so constructed that during contact blow-off the movable contact arm requires relatively little motion to move overcenter in the opening direction. One section of the cam means is constructed so that when the contact arm moves overcenter in the opening direction during contact blowoff, speed of the contact arm is controlled to an extent that contact rebound does not become a problem.

Abstract: A so-called blow-off type current limiting circuit breaker is provided with an elongated movable contact arm that is pivotally mounted at one end thereof on a pin that projects from opposite sides of a support. The contact arm is constructed of parallel sections that are biased toward one another, by spring means disposed remote from the support, with the support being resiliently clamped between the sections to provide a good electrical connection between the support and contact arm. The pivot pin extends through aligned enlarged pivot apertures in the parallel sections to facilitate weld breaking. A wall of each pivot aperture is disposed to cooperate with the pivot pin to achieve a camming action that moves the contact arm slightly lengthwise after initial butting engagement of the circuit breaker main contacts to wipe the engaged contacts with respect to one another.

Abstract: A warning feature for a high voltage controller or the like. A lamp is mounted on the controller cabinet, and connected to an interlock circuit so as to be illuminated whenever line voltage is being supplied to a contactor assembly, regardless of the open or closed status of the contactor itself.

Abstract: A high voltage isolator switch of the double end break type including a central, rotatable insulator carrying a switch blade and a pair of opposed insulators bearing contact assemblies for engaging the ends of the blade. The contact assemblies include pivoted saddles mounted on cantilevered studs and detents to hold the assemblies in an open position.

Abstract: A control for an AC circuit protection system which is capable of monitoring either single phase or polyphase current flow. The composite current envelope is periodically sampled and the sample values converted into digital form. Succeeding current signals are tested to determine whether they deviate from previous samples by a given amount. Non-deviant samples increment a first counter, while deviant samples increment a second counter. The ratio of the counts is used to recognize current imbalance and control system parameters are adjusted to compensate for the imbalance.

Abstract: A watthour meter socket assembly of the type which engages the blades of a watthour meter. The blades are frictionally held by pairs of spring-loaded conductive jaws, which form the female contacts of the socket assembly. Helper springs are provided to increase the biasing of the jaws. In order to provide a conductive bypass when the meter is removed for servicing or replacement a reciprocable, conductive blade is mounted on a slide mechanism so that it can be wedged between the jaws. The wedging action simultaneously spreads the jaws apart, allowing removal of the meter.

Abstract: A gear motor assembly is disposed in a support structure in such a manner that it may rotate in a plane perpendicular to the output shaft thereof. Stops are provided for preventing the shaft from turning past a predetermined point. The motor assembly is located in the support structure by a resilient leaf spring which deflects when the stops are engaged.

Abstract: A permanent magnet rotor configuration which produces four magnetic poles utilizing two sets of symmetrically-disposed permanent magnets. The slots carrying the magnets exhibit a truncated V-shaped configuration, extending from points on the periphery of the rotor to meet the ends of a straight, central portion which lies parallel to a tangent to the rotor shaft. A short magnetic bridge interrupts the center of each slot, the slots being disposed generally symmetrically upon opposite sides of the rotor shaft.

Abstract: A permanent magnet rotor configuration which produces two magnetic poles. Two pairs of axial slots are provided in which permanent magnets are arranged about the rotor shaft. A third, diametrically opposed pair of slots is provided which extend radially outwardly and in which permanent magnets are disposed. Off-axis magnetic bridges are formed on either side of the third slots, separating them from the first and second sets of slots.