Abstract: The present invention provides a new and unique method and apparatus for monitoring a device, such as a pump. The device may also include a fan, compressor, turbine or other rotating or reciprocating piece of machinery. In one embodiment, the method features sensing in a first device both a start-up vibration at a start-up time after the first device is affixed to a second device to be monitored and a subsequent vibration level at a subsequent time after the start-up time, and providing both a start-up vibration level signal containing information about the start-up vibration level of the second device, and a subsequent vibration level signal containing information about the subsequent vibration level of the second device; and monitoring in the first device the condition of operation of the second device based on a comparison of the start-up vibration level signal in relation to the subsequent vibration level signal.

Abstract: The present invention provides a new and unique method and apparatus for monitoring a device, such as a pump. The device may also include a fan, compressor, turbine or other rotating or reciprocating piece of machinery. In one embodiment, the method features sensing in a first device both a start-up vibration at a start-up time after the first device is affixed to a second device to be monitored and a subsequent vibration level at a subsequent time after the start-up time, and providing both a start-up vibration level signal containing information about the start-up vibration level of the second device, and a subsequent vibration level signal containing information about the subsequent vibration level of the second device; and monitoring in the first device the condition of operation of the second device based on a comparison of the start-up vibration level signal in relation to the subsequent vibration level signal.

Abstract: A constant-current AC regulator comprises a switching network including two pulse-width modulator (PWM) transistors and two half-cycle transistors, a PWM transistor driver circuit, a main power transformer with two primary windings, a current sensing network, and an electronic control unit. The control unit generates a multiple pulse train signal with pulse widths based on the difference between the instantaneous load current and a predetermined design load current. The PWM transistor driver converts the pulse train signal into voltage signals appropriate for driving the PWM transformers of the switching network. The instantaneous load current is measured by the current sensing network Each set of a PWM transistor plus a half-cycle transistor carries current during a portion, e.g. half of the AC cycle. Only one primary winding is energized at any instant. Each transistor is preferably an IGBT transistor, and each pair of PWM transistor plus half-cycle transistor may comprise a dual IGBT chip.

Abstract: A constant-current AC regulator comprises a switching network including two pulse-width modulator (PWM) transistors and two half-cycle transistors, a PWM transistor driver circuit, a main power transformer with two primary windings, a current sensing network, and an electronic control unit. The control unit generates a multiple pulse train signal with pulse widths based on the difference between the instantaneous load current and a predetermined design load current. The PWM transistor driver converts the pulse train signal into voltage signals appropriate for driving the PWM transformers of the switching network. The instantaneous load current is measured by the current sensing network Each set of a PWM transistor plus a half-cycle transistor carries current during a portion, e.g. half of the AC cycle. Only one primary winding is energized at any instant. Each transistor is preferably an IGBT transistor, and each pair of PWM transistor plus half-cycle transistor may comprise a dual IGBT chip.