Variable-frequency drive

About: Variable-frequency drive is a research topic. Over the lifetime, 837 publications have been published within this topic receiving 5691 citations. The topic is also known as: VFD.

Real time optimization of power in electrical submersible pump variable speed applications

Abstract: A method and apparatus for real-time monitoring of a variable frequency drive (VFD) controlling an electric submersible pump (ESP) and for fine-tuning operation of a VFD-ESP system such that oil production, power, and motor run life are optimized.

System and method for vibration analysis and phase analysis of vibration waveforms using dynamic statistical averaging of tachometer data to accurately calculate rotational speed

Abstract: Vibration analysis is performed on a machine having a variable frequency drive by using a tachometer to monitor rotational speed of the drive shaft and a logic device to calculate speed parameters associated with the drive shaft using the tachometer data. The speed parameters include a maximum speed, a minimum speed, and an average speed of the drive shaft. By correlating the vibration spectra of the motor drive with the speed parameters, machine faults can be identified based upon the energy distribution in the spectra. Further, vibration waveforms from two or more locations on the machine can be sequentially acquired through synchronous triggering by using a pulse edge of a stable tachometer signal. The waveforms can be compared to determine a phase difference to help in identifying any machine faults that may be present.

Drive control assembly for controlling a motor

Abstract: A drive control assembly for a motor including a variable frequency drive module for providing variable speed control for the motor, a bypass module for providing bypass control for the motor, and a switch for switching control for the motor between the variable frequency drive module and the bypass module. The bypass module can provide control for the motor even when the variable frequency drive module is removed from the drive control assembly.

Clean power common buss variable frequency drive system

Abstract: A N pulse variable frequency drive for driving two or more motors that is the combination of two or more variable frequency drives with each drive driving an associated one of the two or motors One application is a decanter centrifuge which has a main motor to drive the bowl and a back motor to drive the conveyor One of the two variable frequency drives drives the main motor and the other drive drives the back motor The variable frequency drives are connected to a common buss and to a N pulse phase shifting transformer

Surge Test-Based Identification of Stator Insulation Component With Partial Discharge Activity for Low Voltage AC Motors

Abstract: Partial discharge (PD) has been identified as one of the root causes of stator insulation failure even for low voltage (LV) ac motors. For reliable operation of variable frequency drive motors, a standard acceptance test procedure (IEC STD 60034-18-41) to ensure PD-free operation of LV motors was developed. Although the test can verify whether PD exists in the stator for a surge with predetermined voltage level and risetime, the information on where PD activity is present in the stator insulation is not provided. In this article, a test method based on a new variable risetime surge generator is proposed for identifying the component of stator insulation where PD occurs in LV random wound stators. The proposed test allows the user to locate whether PD is in the turn, phase, or ground insulation. This information is critical for lowering the PD inception voltage for improving the motor reliability through insulation system design/manufacturing or motor/drive system reconfiguration. The test is implemented with a 4.5 kV variable risetime surge generator prototype, and seven LV ac motors are tested to show where PD is likely to occur in commercial LV motors.