Abstract: A cable-and-pulley mounted overhead door includes a mechanism for sensing when the cable is tending to slacken and to automatically take-up the slack so as to thereby prevent the cable from disengaging from its pulley. When the overhead door includes an automated drive system, provision is further made for sensing when the take up of slack has progressed to a determined degree and to responsively turn off the automated drive system.

Abstract: A contactor for connecting a medium voltage load, such as a medium voltage three-phase motor, to a medium voltage electrical source, such as a medium voltage three-phase electrical source, and for providing protection functionality for the load includes one or more electrical conductors each having separable contacts such that the load is selectively electrically connected to the source, and one or more current transducers each operatively coupled to a respective one of the electrical conductors for measuring a current thereon. A processor is in electronic communication with the one or more current transducers, and a memory is in electronic communication with the processor. The memory stores one or more routines executable by the processor that are adapted to perform one or more protection functions for the load based on the current measured by each of the one or more current transducers and to selectively open and close the separable contacts of each of said electrical conductors.

Abstract: Hot spots in power conductors are monitored by apparatus comprising a temperature probe embedded in an electrically insulative thermally conductive material in surface-to-surface contact with the power conductor, typically at a joint being monitored. The temperature probe is spaced from the power conductor by the electrically insulative thermally conductive material a distance sufficient to provide electrical isolation, while the material has sufficient thermal conductivity that the temperature probe is able to substantiate trends in temperature changes at the joint. The invention can be incorporated into existing electrically insulative supports for the power conductors.