Abstract: Methods and devices for an extreme duty transformer with wet wound primary and secondary winding encapsulated with a resin and having corrugated insulating material as cooling ducts as a transformer capable of withstanding extreme mechanical stresses in an underground mining environment. The method includes providing a resin impregnated rectangular winding form, forming a secondary winding with alternating layers of magnet wire with a resin impregnated insulating collar above and below the magnet wire and corrugated insulating material extending the full or partial circumference and width of the coil. An insulating layer of corrugated material and resin impregnated insulation is wound to separate the primary from the secondary windings.

Abstract: A rigid bar of material is fastened to a circuit board to increase its stiffness. The bar is preferably a high modulus plastic such as liquid crystal polymer. Flexible fingers which surround a central opening are formed integrally with the bar and pop into throughbores in the circuit board. Each finger has at least one arcuate protrusion and, preferably several, which can engage the bottom of the circuit board. A rigid pin which may be made of steel is slid into the central opening and has an interference fit therewith to hold it in place to prevent flexible fingers from moving inwardly so the stiffener is held fast to the circuit board. In one embodiment, the stiffener has an I-beam cross section and arches enhancing the resistance to bending.

Abstract: A rigid bar of material is fastened to a circuit board to increase its stiffness. The bar is preferably a high modulus plastic such as liquid crystal polymer. Flexible fingers which surround a central opening are formed integrally with the bar and pop into throughbores in the circuit board. Each finger has at least one arcuate protrusion and, preferably several, which can engage the bottom of the circuit board. A rigid pin which may be made of steel is slid into the central opening and has an interference fit therewith to hold it in place to prevent flexible fingers from moving inwardly so the stiffener is held fast to the circuit board.

Abstract: A circuit breaker power distribution panel which is constructed in the form of a single unit. The panel includes an electrically insulative base which include first and second electrical connectors that are to respectfully removably connect to mating electrical terminals of a circuit breaker. The circuit breaker is to be removably connected to the panel. Imbedded within the panel and mounted on the electrically insulative base is an input busbar and an output busbar. The first electrical connector is part of the input busbar. The input busbar is electrically connected to the circuit breakers with the power from the circuit breakers being transmitted to the second electrical connectors which are also imbedded within the panel. A load terminal connects with each second electrical connector with there being a separate load terminal for each second electrical connector. There is a separate load for each circuit breaker.

Abstract: A vacuum load break switch uses a vacuum interrupter for the load break device together with a series connected visible disconnect which is interlocked with the vacuum interrupter mechanism. Further, the visible disconnect is grounded in the fully opened switch position. A manual switch operator is provided together with interconnect means interconnecting the manual switch operator to both the visible disconnect switch means and the vacuum interrupter in a manner such that in a switch closing operation of the manual switch operator the visible disconnect switch means closes before the vacuum interrupter means and in an opening operation the vacuum interrupter means opens before the visible disconnect switch means. Additionally, an additional solenoid operated switch operator is coupled to the interconnect means for opening the vacuum interrupter through solenoid action.

Abstract: An electrical plug and receptacle assembly in which the number of different parts is minimized, is characterized by the use of an identical insulator in both the plug housing and the receptacle housing. The insulator has contact compartments adapted to mount either male or female contacts. Both the male and female contacts include an integral cable terminal. Additionally, the female contacts are segmented and include spring means for biasing the female contacts into tight engagement with male contacts. A cable clamp is also provided with the plug assembly which can effectively clamp either round or flat cables.