Abstract: A detecting apparatus for AC motor malfunction by using a current delay property of an AC motor and outputting a malfunction signal to an alarming device is presented. The detecting apparatus for AC motor malfunction includes a voltage phase delay setting unit, a voltage phase conversion unit, a current phase detecting unit, a current phase conversion unit, a phase comparator, a sawtooth wave generating unit, a phase difference detecting unit, a phase shift bandwidth setting unit, a noise filtering unit, and a malfunction signal output unit.

Abstract: An early electrical fire sensing system for a high voltage panel, a low voltage panel, a motor control panel, a distribution board, or a power distribution panel comprises the first laser that emits the frequency beam absorbed by benzyl alcohol gas and the first detecting device which detects the first beam intensity; the second laser which emits the frequency beam absorbed by BHT gas and the second detecting device which detects the second laser beam intensity; and a main control unit which consists of a microprocessor. The main control unit gives a fire alarm event when the first laser beam intensity of the first detecting device is decreased more than a reference value, while a fire emergent alarm event when the second laser beam intensity of the second detecting device is decreased more than a reference value.

Abstract: An early electrical fire sensing system for a high voltage panel, a low voltage panel, a motor control panel, a distribution board, or a power distribution panel comprises the first laser that emits the frequency beam absorbed by benzyl alcohol gas and the first detecting device which detects the first beam intensity; the second laser which emits the frequency beam absorbed by BHT gas and the second detecting device which detects the second laser beam intensity; and a main control unit which consists of a microprocessor. The main control unit gives a fire alarm event when the first laser beam intensity of the first detecting device is decreased more than a reference value, while a fire emergent alarm event when the second laser beam intensity of the second detecting device is decreased more than a reference value.