Abstract: A variable frequency motor drive comprises a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power. A DC bus is connected to the rectifier circuit. At least one bus capacitor is across the DC bus. An inverter receives DC power from the DC bus and converts the DC power to AC power to drive a motor. A controller is operatively connected to the converter. The controller comprises a speed control controlling the inverter responsive to a speed command to maintain a desired motor speed. A speed foldback control measures DC bus ripple voltage and regulates the speed command responsive to the measured DC bus ripple voltage.

Abstract: A variable frequency motor drive comprises a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power. A DC bus is connected to the rectifier circuit. At least one bus capacitor is across the DC bus. An inverter receives DC power from the DC bus and converts the DC power to AC power to drive a motor. A controller is operatively connected to the converter. The controller comprises a speed control controlling the inverter responsive to a speed command to maintain a desired motor speed. A speed foldback control measures DC bus ripple voltage and regulates the speed command responsive to the measured DC bus ripple voltage.

Abstract: An electrical enclosure assembly comprises an enclosure having walls defining an interior space for housing electrical components and having a front flange surrounding a front opening. A cover is hingedly mounted to the enclosure for selectively closing the front opening. The cover comprises a front wall larger than the front opening and a rearwardly extending peripheral rim. Cooling structure is integrally formed on an interior surface of the cover proximate the peripheral rim. The cooling structure comprises a plurality of spaced apart cooling ribs each having a shoulder engaging the enclosure front flange when the cover is in a closed position to provide an air flow path between the interior space and outside of the enclosure through spaces between the cooling ribs.

Abstract: An electrical enclosure assembly comprises an enclosure having walls defining an interior space for housing electrical components and having a front flange surrounding a front opening. A cover is hingedly mounted to the enclosure for selectively closing the front opening. The cover comprises a front wall larger than the front opening and a rearwardly extending peripheral rim. Cooling structure is integrally formed on an interior surface of the cover proximate the peripheral rim. The cooling structure comprises a plurality of spaced apart cooling ribs each having a shoulder engaging the enclosure front flange when the cover is in a closed position to provide an air flow path between the interior space and outside of the enclosure through spaces between the cooling ribs.