The present disclosure relates to a contactor and an operation method thereof. The contactor includes a contact, a control device, a wear indication and reset device, and a memory. The control device generates and stores wear diagnosis alarm information when the contactor is disconnected; generates a switch control signal based on the wear diagnosis alarm information when the contactor is powered on. A switch unit in the wear indication and reset device enters a wear indication state based on the switch control signal, and receives a user's operation to enter a reset state. The control device receives switch state information of the switch unit, and stores it when the contactor is disconnected. When the contactor is powered on, the control device clears the wear diagnosis alarm information based on the received switch state information being the reset state and the switch state information stored being the wear indication state.

A method for diagnosing the cause of tripping of an electrical protection device includes, after detection by the auxiliary device of a loss of electrical power, determining a type of electrical fault on the basis of recorded values, the determining operation including: comparing, with a first threshold value, the largest value of the maximum intensity of the current from the recorded values for a plurality of measurement intervals preceding the loss of power, a short circuit being diagnosed if the largest value of the maximum intensity is greater than a first threshold value; comparing, with a second threshold value, the largest RMS value of the current from the recorded values, an overload being diagnosed if the largest RMS value is greater than a second threshold value.

A method for automatically testing a relay is provided. The method includes applying power to a testing device for automatically testing the relay, determining a position of a selector switch based on a user selection for testing, selectively energizing the relay based on the position of the selector switch, detecting, by a hardware processor, an energize status signal from the selector switch, testing, by the hardware processor and based at least on the energize status signal, a control coil or a contact of the relay to generate a test result, and displaying, using display, the energize status signal and the test result.

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.

Devices herein may include conductor lines connected between a power supply and load, each of the conductor lines coupled to an AC contactor and a contactor control circuit, wherein the contactor control circuit is operable to open and close one or more contactors of the AC contactor. The devices may further include a current transformer coupled to the conductor lines, the current transformer operable to output a secondary current corresponding to a primary current magnitude of an electrical current not flowing to the load, wherein the AC contactor is connected between the power supply and the load. Devices may further include a zero cross detection circuit operable to generate an interrupt at each of a plurality of zero crossings for a microprocessor, and determine whether to open the one or more contactors of the AC contactor in a predetermined optimum interval calculated with respect to the zero crossing points.

Devices herein may include conductor lines connected between a power supply and load, each of the conductor lines coupled to an AC contactor and a contactor control circuit, wherein the contactor control circuit is operable to open and close one or more contactors of the AC contactor. The devices may further include a current transformer coupled to the conductor lines, the current transformer operable to output a secondary current corresponding to a primary current magnitude of an electrical current not flowing to the load, wherein the AC contactor is connected between the power supply and the load. Devices may further include a zero cross detection circuit operable to generate an interrupt at each of a plurality of zero crossings for a microprocessor, and determine whether to open the one or more contactors of the AC contactor in a predetermined optimum interval calculated with respect to the zero crossing points.

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 invention relates to a control unit for a medium voltage switching apparatus. The control unit is adapted to carry out a diagnostic method to check operating conditions of one or more components of said electric poles. The diagnostic method includes the following steps: basing on a selected ideal position curve, obtaining one or more first curves indicative of an ideal behaviour of said switching apparatus, during an opening manoeuvre or closing manoeuvre of the switching apparatus; basing on detection signals provided by a closed-loop control arrangement of said control unit, calculating one or more second curves indicative of an actual behaviour of said switching apparatus, during an opening manoeuvre or closing manoeuvre of said switching apparatus; and carrying out a comparison procedure among said first and second curves.

A circuit breaking apparatus comprises a circuit breaker, a motor drive system, and a controller. The circuit breaker is electrically connectable to a power line. The motor drive system is mechanically coupled to the circuit breaker and configured to operate the circuit breaker such as to perform a movement including at least an opening movement from a closed position to an open position, thereby electrically interrupting the power line. The controller includes a model of at least one of the motor drive system and the circuit breaker.

The controller is configured to receive reference travel curve information of the movement; generate actuator information from the reference travel curve information based on the model; and output the actuator information.

A circuit breaker includes a capacitive voltage sensor located within its insulating casing. The voltage sensor includes a capacitor located between the terminals of the circuit breaker adjacent a low potential surface provided by a coil of a current sensor. The capacitor is dome shaped. The voltage sensor does not appreciably increase the size or weight of the circuit breaker and is reliable and accurate.