Patent attributes
A material handler comprises a motor, an interface device, and a controller. The controller is configured to receive an input from the interface device and can include a variable frequency drive (VFD). The controller provides a variable frequency drive (VFD) signal to the motor to control movement of one or more components of the material handler. If the interface device is inactive for a predetermined amount of time, the controller adjusts a frequency of the VFD signal from an operating frequency to a standby frequency with the standby frequency being lower than the operating frequency. Adjusting the frequency from the operating frequency to the standby frequency can include adjusting the frequency of the VFD signal to one or more intermediate frequencies. When adjusting the frequency of the VFD signal, the controller can skip at least one frequency or range of frequencies, for example, to avoid undesirable operating characteristics.
