Abstract: A motor drive receives a position feedback signal from an encoder operatively connected to the motor. The motor drive executes a speed regulator module on a first periodic interval to achieve desired operation of the motor, and the motor drive executes an additional module at a second periodic interval, occurring more frequently than the first periodic interval, to increase the resolution of the position feedback. The position feedback signal is provided as or converted to counts. The motor drive maintains a first counter with a running total of each count received as well as a second counter which generates a higher resolution value than the first counter. During each second periodic interval the motor drive increments the high-resolution counter by the number of actual counts detected within the corresponding first periodic interval. This high-resolution counter is used by the speed regulator to obtain desired operation of the motor.

Abstract: A system and method for detecting a brake dragging during normal operation of a motor monitors torque at zero speed and at constant speed. For an inertial system acted upon by gravity, a value of torque required to maintain zero speed is approximately the same as a value of torque required to maintain operation at a constant speed. In an exemplary, elevator system, a motor drive determines the torque required to maintain zero speed operation of an elevator cab after a holding brake opens and before it begins controlling the motor to rotate. The motor drive again determines the torque required to maintain a constant speed and compares this value to the value of torque required to maintain zero speed. If the difference between the two values of torque is greater than a predefined threshold, then the motor drive determines that the brake is dragging and sets an error message.

Abstract: A motor drive receives a position feedback signal from an encoder operatively connected to the motor. The motor drive executes a speed regulator module on a first periodic interval to achieve desired operation of the motor, and the motor drive executes an additional module at a second periodic interval, occurring more frequently than the first periodic interval, to increase the resolution of the position feedback. The position feedback signal is provided as or converted to counts. The motor drive maintains a first counter with a running total of each count received as well as a second counter which generates a higher resolution value than the first counter. During each second periodic interval the motor drive increments the high-resolution counter by the number of actual counts detected within the corresponding first periodic interval. This high-resolution counter is used by the speed regulator to obtain desired operation of the motor.

Abstract: A method and system for reducing rollback in a counterbalancing system as a holding brake is released is disclosed. A limited amount of movement of a drive shaft is present in the holding brake. A motor drive provides current to the motor with the holding brake set such that a torque is applied at the drive shaft. The current is controlled to generate torque in both directions. The limited amount of movement in the brake may be used to determine a direction and magnitude of torque required to support a mechanical load being applied to the motor. The motor drive then provides a current to generate the necessary torque required to support the load prior to releasing the holding brake.

Abstract: A method and system for reducing rollback in a counterbalancing system as a holding brake is released is disclosed. A limited amount of movement of a drive shaft is present in the holding brake. A motor drive provides current to the motor with the holding brake set such that a torque is applied at the drive shaft. The current is controlled to generate torque in both directions. The limited amount of movement in the brake may be used to determine a direction and magnitude of torque required to support a mechanical load being applied to the motor. The motor drive then provides a current to generate the necessary torque required to support the load prior to releasing the holding brake.

Abstract: A system for determining the angular position of a synchronous motor includes an encoder with a friction wheel engaging a rotating surface of the motor. The friction wheel is spun by the rotation of the motor, and the encoder generates a signal corresponding to the angular position of the friction wheel. An independent, sensor is provided to generate a pulse once per revolution of the motor. The independent sensor detects the presence of a target on the rotating surface of the motor and generates the pulse when the target is proximate to the sensor. A controller receives the signal corresponding to the angular position of the friction wheel as well as the pulse generated by the independent sensor to determine the angular position of the motor. The controller compensates the angular position of the motor each time the pulse is generated, correcting accumulated position error.

Abstract: A system for determining the angular position of a synchronous motor includes an encoder with a friction wheel engaging a rotating surface of the motor. The friction wheel is spun by the rotation of the motor, and the encoder generates a signal corresponding to the angular position of the friction wheel. An independent, sensor is provided to generate a pulse once per revolution of the motor. The independent sensor detects the presence of a target on the rotating surface of the motor and generates the pulse when the target is proximate to the sensor. A controller receives the signal corresponding to the angular position of the friction wheel as well as the pulse generated by the independent sensor to determine the angular position of the motor. The controller compensates the angular position of the motor each time the pulse is generated, correcting accumulated position error.

Abstract: Golf putter apparatus includes a golf putter, a laser light generator and mirror mounting structure inserted in the shaft maintaining proper positioning of a mirror used to reflect laser light from the laser light generator and operable to hold the mirror in stable fixed position and orientation.

Abstract: A portable jig for cutting a plurality of building materials quickly, uniformly and accurately, which may be quickly assembled and reassembled for easy transport and maintenance. The jig includes a platform, a deck, a deck fence, an optional platform fence, and two rails. The rails are removably and securably connectable to the fixed platform and passable through the deck, such that both rails are separated from each other. The deck fence is reversibly joinable to the deck. When the platform fence is included, the platform fence is reversibly joinable to the platform. While building materials are laid upon the jig for cutting, a cutting device, such as a circular saw blade, may be passed near and along either of the deck or platform fences to effect this cutting of one or both ends of the building materials. The jig further includes an optional support member for supporting the jig when it is being used.

Abstract: The present disclosure relates to a refrigeration system including a compressor for compressing a refrigerant, a condenser in fluid communication with the compressor for condensing compressed refrigerant received from the compressor, and a reservoir in fluid communication with the condenser for holding condensed refrigerant received from the condenser. The system also includes a heat exchanger in fluid communication with the reservoir, an expansion device in fluid communication with the heat exchanger for decompressing cooled refrigerant received from the heat exchanger, and at least one evaporator in fluid communication with the expansion device for evaporating decompressed refrigerant received from the expansion device.