Abstract: A method of generating a landing speed pattern which starts with the dynamics of the actual elevator system and the desired actual landing velocity profile curve, and generates a landing speed pattern which will produce the desired actual landing velocity characteristic. In a preferred embodiment, the actual desired landing velocity is a function of time squared, defining a parabolic profile. The apparatus includes arrangements for implementing a predetermined speed pattern equation in response to the distance-to-go count (DTG) of predetermined standard increments to the target floor.

Abstract: An elevator system in which distance pulses are generated in response to travel of an elevator car, and used to update a car position counter. The difference between the car position count and a count representative of the location of the target floor is determined when the elevator car reaches a predetermined distance from the target floor, and this distance-to-go (DTG) count is used to provide a speed pattern for decelerating and landing the car at floor level. A zone of fixed length is provided on each side of each floor, and, when this zone is detected, the DTG count is compared with a count representative of this fixed length. If they differ within a predetermined tolerance, it is known that a proper landing will or can be made, and the DTG count is changed to the correct value at the instant the zone is detected. Door preopening may be enabled at this time. If the difference exceeds the predetermined tolerance, no corrective action is taken, and door preopening is not enabled.

Abstract: An elevator system having an elevator car, a DC drive motor for driving the elevator car, an adjustable voltage DC source for the drive motor, overvoltage and overacceleration detectors responsive to the armature voltage of the drive motor, test apparatus for testing the operability of the detectors during each run of the elevator car, and a protective circuit. The protective circuit initiates an emergency stop of the elevator car in response to overvoltage, or overacceleration, and it prevents the elevator car from starting a new run when the test apparatus detected a malfunction during the prior run.

Abstract: An elevator system including an elevator car and a drive machine having a DC drive motor, a dual converter, and a phase controller for providing gate drive signals for the dual converter. A reference signal relates to the desired motor armature current is developed in response to the operation of the elevator system. The reference signal indicates when the current source should be switched from one converter bank to the other converter bank. The switching is accomplished by a method which includes retarding the firing angle of the gate drive signals applied to the operative converter, until current is extinguished, applying the gate drive signals to the other converter bank, and advancing the firing angle towards rectification to initiate current flow in the on-coming converter. The rate at which the firing angle is advanced towards rectification is a function of the control signal.