Magnetek, Inc.

Kurtis L Verheyen

Aaron S Kureck

Casey Cummins

Jacob C Lester

Gregory A Byzewski

A motor controller detects the speed at which a driven member is travelling when it enters a slow-down region of a material handling system. Using this speed and a deceleration rate, the motor controller determines a required slow-down distance to reach a desired slow speed. A traverse distance is determined as a difference between the length of the slow-down region the slow-down distance. The traverse distance extends for a first portion of the slow-down region and the slow-down distance extends for the second portion of the slow-down region. While the driven member is located within the traverse distance, the driven member may continue operating at the speed at which it entered the slow down region. When the driven member reaches the slow-down distance, the motor controller begins decelerating the driven member.

Dynamic maximum frequency in a slow-down region for a material handling system

A method and system to prevent unexpected operation of a motor when the voltage level on a DC bus drops is disclosed. The voltage level on the DC bus is monitored during a run command. When a run is commanded, the processor executes a control routine to determine a desired amplitude and frequency for the output voltage required to control the motor connected to the motor drive. If the desired frequency of the output voltage exceeds a maximum frequency for the measured voltage on the DC bus, as established by parameters stored in the motor drive, the motor drive limits the output frequency to the maximum frequency for the corresponding measured voltage. The motor drive continually monitors the measured voltage present on the DC bus and further reduces the maximum output frequency allowed during the run if the present value of the measured voltage drops below a previously measured value.

Method and apparatus for low DC bus voltage ride through

A system and method for determining the load in a material handling system is disclosed. The load weight detection system measures torque at four operating conditions both at constant speed and during acceleration. The level of torque generated by the motor under each of these operating conditions is stored in the motor drive. The motor drive also receives a signal corresponding to the speed of the hoist motor. Based on the measured torque, as well as the expected torque at no load and at rated load for the measured speed, the motor drive then determines the load present on the hoist. In some systems, two or more hoists are required to operate in tandem to lift a load. Each motor drive determines the weight of the load supported by its respective hoist motor and determines a total weight of the load based on the weights determined by each motor drive.

System and method for determining a load in a material handling system

A control system for a bucket hoist includes a two-axis master switch configured to generate a first and a second command signal responsive to motion along each axis. Each command signal is provided to one of a pair of motor controllers configured to control one of a pair of motors. The two motors are controlled to raise/lower and open/close the load handling member. When the two-axis master switch is moved to the close position, the closing motor controller is commanded to control its respective motor to begin closing the load handling member. The holding motor controller is configured to generate a current to its respective motor to generate torque at a predefined level. The predefined level of torque is selected such that the load handling member lowers into the material in which it is digging as it is being closed.

Method and apparatus for controlling a bucket hoist

A system and method for determining the load present in a material handling system is disclosed. A commissioning routine executing on a motor drive controls operation of a hoisting motor with a known load present. The commissioning routine stores values of current provided to the motor or torque generated by the motor at various operating speeds in memory on the motor drive. During subsequent runs of the motor drive, the value of the current/torque is monitored as a function of the speed of the motor and compared to the stored values. The resulting value of the load may be monitored and action taken if the value of the load exceeds the rated capacity of the material handling system. Optionally, the measured load may be displayed to an operator.

Method and apparatus for measuring a load in a material handling system

A system and method for determining the holding torque of a brake in a material handling system is disclosed. The material handling system may include a bridge, a trolley, and a hoist, each driven along a different axis by a motor. A brake is operatively coupled to the motor to prevent unwanted motion of the motor. A motor controller is coupled to each motor which controls operation of the motor and its corresponding brake. The motor controller generates a torque command to the motor while keeping the brake set. The initial torque command is less than the holding torque of the brake. The torque command is incremented until motion is detected on the motor. The torque value when motion is detected is stored in the motor controller and displayed to an operator.

Method and apparatus for calibrating and testing brake holding torque

A variable speed power converter controls the speed of a load in a material handling system as a function of the torque required to move the load. While the power converter is running, the torque being produced in the motor is determined. The power converter then determines the maximum rotational speed of the motor as a function of the torque currently being produced and of the torque-speed curve of the motor. The power converter then commands the motor to rotate at this maximum rotational speed. The power converter periodically monitors the torque being produced and adjusts the maximum rotational speed of the motor throughout the run.

Growing community of inventors

Shorewood, WI, United States of America

Kurtis L Verheyen