Abstract: A pulse wheel system including a pulse wheel and first and second detectors responsive thereto for providing first and second pulse trains having a predetermined phase shift between them. The detectors are mounted on a mounting plate which positionally relates the first and second detectors to the center of the pulse wheel, eliminating set-up adjustments.

Abstract: A traction elevator system having an elevator car driven by a dual converter bank, solid state motor drive. The solid state motor drive includes bank selection circuits, which select the operative converter bank at any instant, and firing circuits for providing firing pulses for the selected converter bank. The energization and deenergization of the bank selection circuits and firing circuits are controlled such that the bank selection circuits are energized before the firing circuits, and, upon loss of power, the bank selection circuits are deenergized after the firing circuits.

Abstract: A digital tachometer in which first pulses are produced at a rate proportional to the speed of a device. Second pulses are produced at a constant rate which exceeds the maximum rate of the first pulses, and a binary counter provides a binary count of the second pulses produced between two consecutive first pulses. A look-up table memory provides several blocks of addressable storage locations containing digital representations of speed. The MSB of the binary count selects a specific block of the memory, and the address of the selected block is derived from the binary count.

Abstract: A speed switch for an elevator system which obtains its information from distance pulses generated in response to car travel. The reference speed setting of the switch is a function of the desired predetermined speed at which the switch is to operate, the number of distance pulses produced per inch of car travel, and the time required by a counter to count to a predetermined value. This arrangement facilitates the selection of the reference speed setting of the speed switch, such as by using a thumb switch. An emergency terminal stopping arrangement using the speed switch is also disclosed, as is a new and improved elevator system in which the normal slow-down speed pattern and emergency terminal stop functions are both resposive to distance pulses produced in response to car movement, enabling a terminal slow-down speed pattern to be initiated by circuitry independent of the distance pulses, such as via a notched terminal slow-down blade adjacent to each terminal floor.