An air conditioner includes an outdoor unit, a relay circuit which includes a contact and a relay coil, and a control unit which causes a first voltage equal to or higher than an operating voltage or a second voltage lower than the operating voltage and equal to or higher than a retention voltage to be applied to the relay coil. One end portion of the contact is connected to an alternating-current power supply and the other end portion of the contact is connected to the outdoor unit. One end portion of the relay coil is connected to a power supply for driving the relay circuit. The control unit causes a second voltage to be applied to the relay coil after the contact is turned ON, and causes the first voltage to be applied to the relay coil at a predetermined constant period.

A relay device may include an armature that moves between a first position that electrically couples the armature to a first contact and a second position that electrically couples the armature to a second contact. The relay device may also include a relay coil that receives a voltage to magnetize the relay coil, thereby causing the armature to move from the first position to the second position. The relay device may also include a drive circuit that couple the voltage to the relay coil, such that the voltage is higher than a rated voltage associated with the relay coil.

A method may include receiving, via one or more processors, back electromotive force (EMF) data associated with each motor electrically coupled to a printed circuit board and determining, via the processors, a corresponding motor controller associated with each motor based on the EMF data. The motor controllers may be electrically coupled to the printed circuit board. The method may also include automatically adjusting, via the processors, circuit connections associated with the printed circuit board to route wiring that controls each motor to the corresponding motor controller.

A control system may include a processor that may receive a first dataset associated with power properties of a rotating load device coupled to a relay device. The processor may also determine frequency properties based on the power properties and determine a switching profile to control moving a first armature of three armatures in the relay device based on the frequency properties. The switching profile is configured to control movement of the first armature between a first position and a second position, and wherein the switching profile comprises a firing angle for moving the first armature with respect to an electrical waveform, a second armature, and a third armature. The processor may then control a current provided to a relay coil of the relay device based on the switching profile, such that the relay coil causes the first armature to move.

Systems and methods for contact erosion mitigation are provided. To perform contact erosion mitigation, an order of opening/closing poles and/or contact relays of particular poles is altered, resulting in a sharing of potential arcing conditions amongst the poles/contact relays of these poles.

The electromagnetic relay includes a fixed terminal, a fixed contact connected to the fixed terminal, a movable contact piece moving in an opening direction and a closing direction with respect to the fixed terminal, a movable contact connected to the movable contact piece and being arranged to face the fixed contact, a coil generating an electromagnetic force to move the movable contact piece, and a drive circuit controlling a current to the coil. The drive circuit increases the current at a first increase rate in a first period that includes a period from a start time when the current starts to flow in the coil to before a contact time point at which the movable contact contacts the fixed contact. The drive circuit increases the current at a second increase rate larger than the first increase rate in the second period that includes a period after the contact time point.

A power contact health assessor system includes a pair of terminals adapted to be connected to a set of switchable contact electrodes of a power contact and a contact separation detector configured to determine a time of separation of the set of switchable contact electrodes during deactivation of the power contact. The system includes a controller circuit operatively coupled to the pair of terminals and the contact separation detector. The controller circuit is configured to determine within a first observation window, a plurality of contact stick durations and an average contact stick duration. One or more additional observation windows with corresponding average contact stick durations are configured. A health assessment for the set of switchable contact electrodes may be based on a subsequent contact stick duration for a contact cycle after the first observation window and the corresponding average contact stick durations for the one or more additional observation windows.

An electrical circuit includes a contact with a pair of switchable electrodes, the contact configured to cycle through make and break transitions while conducting current. The electrical circuit further includes an arc suppressor, at least one sensor, and a controller circuit. The arc suppressor is coupled across the pair of switchable electrodes and is to extinguish an arc formed across the pair of switchable electrodes during the make and break transitions of the contact. The at least one sensor is coupled to the pair of switchable electrodes and is configured to generate sensor data. The controller circuit includes a plurality of registers and is configured to detect a fault condition associated with the contact based on the sensor data. The controller circuit further sequences contact opening of the contact based on the detected fault condition and a timing value stored in at least one register of the plurality of registers.

An arc suppressing circuit configured to suppress arcing across a power contactor coupled to an alternating current (AC) power source having a predetermined number of phases, each contact of the power contactor corresponding to one of the predetermined number of phases includes a number of dual unidirectional arc suppressors equal to the predetermined number of phases of the AC power source. Each dual unidirectional arc suppressor includes a first phase-specific arc suppressor configured to suppress arcing across the associated contacts in a positive domain, a a second phase-specific arc suppressor configured to suppress arcing across the associated contacts in a negative domain, and a coil lock controller, configured to be coupled between a contact coil driver of the power contactor, configured to detect an output condition from the contact coil driver and inhibit operation of the first and second phase-specific arc suppressors over a predetermined time.

A power contact fault clearing device includes a first pair of terminals adapted to be connected across a first set of switchable contacts, and a second pair of terminals adapted to be connected across a second set of switchable contacts. The second set of switchable contacts coupled to an arc suppressor. A current sensor is adapted to be connected between a power load and the second set of switchable contacts. The current sensor is configured to measure a power load current associated with the power load. A controller circuit is operatively coupled to the current sensor and the first and second pairs of terminals. The controller circuit is configured to detect a fault condition based at least on the power load current, and sequence deactivation of the first set of switchable contacts and the second set of switchable contacts based on the detected fault condition.