Abstract: A method and system of flicker suppression for an LED 26. The method includes providing a power supply 10 for supplying current to the LED 26. The power supply 10 includes a flicker suppressor 50 and is responsive to a dim command signal. The method further includes receiving the dim command signal at the power supply 10, switching the current on and limiting the current to maintain LED light output below 110 percent of the LED light output corresponding to the dim command signal.

Abstract: A magnetic ballast fault isolation system and method, with a fault isolation system including a magnetic ballast 22 having a current input 24, the magnetic ballast 22 having an operational current rating and an inrush current rating; and a fast acting fuse 26 operably connected in series with the current input 24, the fast acting fuse 26 having a continuous current rating and an overload current rating. The amperage of the fast acting fuse 26 is selected for the larger of the continuous current rating for a predetermined current factor times the operational current rating and the overload current rating for the inrush current rating.

Abstract: A method and system of flicker suppression for an LED 26. The method includes providing a power supply 10 for supplying current to the LED 26. The power supply 10 includes a flicker suppressor 50 and is responsive to a dim command signal. The method further includes receiving the dim command signal at the power supply 10, switching the current on and limiting the current to maintain LED light output below 110 percent of the LED light output corresponding to the dim command signal.

Abstract: Battery powered variable speed motor drives typically control the speed of the motor in accordance with a speed command. If the battery discharges to a point where the speed command is greater than that speed which can be supported by the battery voltage, the current drawn from the battery by the motor increases, thereby accelerating discharge of same. This problem is obviated by a control for an AC motor drive according to the present invention which includes means for deriving a signal from the output of the battery representing the maximum motor speed which the battery voltage can support, means for summing the maximum motor speed signal with the speed command signal to derive an error signal and means for summing the error signal with the speed command signal when the commanded speed is greater than that speed which can be supported by the battery voltage to reduce the speed command to the inverter and thereby maintain a predetermined voltage to frequency relationship in the inverter output.

Abstract: Prior circuits for protecting inverter switches from the possibility of overlapping operation which may cause shoot-through have required complex and expensive delay circuits to provide a fixed delay between turn-off of one switch and turn-on of the complementary switch. In order to overcome the problem of complexity and expense, a protection circuit according to the present invention includes a drive signal source for developing complementary first and second drive signals and first and second drive logic circuits coupled to the drive signal source for controlling first and second switching devices, respectively, in response to the drive signals so that overlapping operation is prevented. Each of the drive logic circuit includes an inhibit logic circuit having first and second inputs which receive the drive signal and an inhibit signal developed by the other drive logic circuit, respectively.

Abstract: AC motor drives which include static inverters typically are operated by inverter controls that are designed according to certain criteria so that the inverter is operated in an efficient manner. Generally, it is desirable to design such a control to reduce as much as possible losses in the motor windings and losses associated with the inverter switches. However, inverters switching losses cannot be reduced without increasing motor losses, and vice versa, since motor losses decrease with increasing PWM frequency while inverter losses decrease with decreasing PWM frequency. In order to overcome this problem, a control system according to the present invention for controlling an inverter which converts DC power into variable frequency AC power for energizing a motor in accordance with an input command includes circuitry coupled to the input command for generating a plurality of waveforms at different frequencies, each frequency being an integer multiple of the frequency of the AC output.