Abstract: A monitoring apparatus is connected, in parallel with a motor, to a plurality of power supply lines. Each of the power supply lines has a different phase. The monitoring apparatus includes a first isolator that selectively allows a first current to flow from a first power supply line to a second power supply line. A second isolator selectively allows a second current to flow from the second power supply line to a third power supply line. A control module controls the first isolator, controls the second isolator, and receives a first signal corresponding to a total current. The total current includes both the first current and the second current. The control module selectively generates a phase failure signal in response to the first signal indicating that a failure of at least one of the power supply lines has occurred.

Abstract: A method includes receiving N power signals, each having a different one of N phases, over N power supply lines, where N is an integer greater than two. The method further includes selectively activating a first switch to allow a first current to flow from a first one of the N power supply lines to a second one of the N power supply lines. The method includes generating a signal based on the first current, and selectively generating a phase failure signal when the signal is less than a predetermined threshold.

Abstract: A method includes receiving N power signals, each having a different one of N phases, over N power supply lines, where N is an integer greater than two. The method further includes selectively activating a first switch to allow a first current to flow from a first one of the N power supply lines to a second one of the N power supply lines. The method includes generating a signal based on the first current, and selectively generating a phase failure signal when the signal is less than a predetermined threshold.

Abstract: A method includes receiving N power signals, each having a different one of N phases, over N power supply lines, where N is an integer greater than two. The method further includes selectively activating a first switch to allow a first current to flow from a first one of the N power supply lines to a second one of the N power supply lines. The method includes generating a signal based on the first current, and selectively generating a phase failure signal when the signal is less than a predetermined threshold.

Abstract: An apparatus includes a first optocoupler and a control module. The first optocoupler selectively allows a first current to flow from a first one of a first pair of N power supply lines to a second one of the first pair. N is an integer greater than two. The N power supply lines each provide a phase signal. The control module controls the first optocoupler and determines an occurrence of a phase failure of the phase signals based on a first signal, which is based on the first current.

Abstract: An apparatus includes a first optocoupler and a control module. The first optocoupler selectively allows a first current to flow from a first one of a first pair of N power supply lines to a second one of the first pair. N is an integer greater than two. The N power supply lines each provide a phase signal. The control module controls the first optocoupler and determines an occurrence of a phase failure of the phase signals based on a first signal, which is based on the first current.