A Cogging DC Motor
A three-hundred horsepower DC motor in the paper industry was cogging. Data collected,
analysis and solutions to the problem are presented.
A VFD and Speed Fluctuations
A VFD in the food processing industry was giving erratic speed changes. Data collected,
analysis and solutions to the problem are presented.
Motor and Control Burn Out Together
Two cases histories: A control failure caused the motor to burn out in one case, and a motor
failure caused the control to burn out in another case.
An Overloaded Dough Mixer
A variety of application considerations are presented in selecting a solution to the problem.
EMI/RFI and a Magnetic Resonance Imaging Machine: A problem
created by three Variable Frequency Drives
EMI/RFI generation can indeed cause serious problems.
Overloaded VFD Due to Harmonic Current Generation
Motor nameplate amps could be within the rating of a drive. However, if the motor draws
additional harmonic current of five to six per cent then a drive that is sized marginally
may give an overload trip.
Skullduggery Afoot!
He sure looked honest!
EMI/RFI Solutions
VFDs interfered with a lonworks system