Systems and methods are provided for releasing welded-shut contactors of a contactor system. An exemplary contactor system may include a contactor and a controller. The controller may be programmed to command a vibration across portions of the contactor as part of a weld release control strategy when the contactor is welded closed. The vibration may be achieved by repeatedly alternating between energizing and de-energizing a coil of the contactor in order to mechanically shock/vibrate a welded contact of the contactor.

The present invention relates to a contactor, a connector and a contactor component. According to the first aspect of the invention, a contactor relates to a switch mechanism, an iron core, an iron core position sensing circuit and a control circuit. The control circuit can measure the position of the iron core by measuring the variation in inductance by using the property that the coil can produce different inductances when the iron core is in different positions in the coil. According to the second aspect of the invention, a connector and contactor component are provided, wherein a control circuit is arranged on a connector, the control circuit comprises a PWM power-saving circuit. The PWM power-saving circuit is integrated on the connector, so that the average driving current of the contactor is reduced and meanwhile, the size of the contactor is reduced.

A method for sensing a welded relay contact when breaking both sides of a power line on a HVAC device including the steps: applying a first signal to one of a pair of switching devices; electronically sensing a second signal, with a sensing device, whether the other of said two switching devices is welded closed; and sending a third signal from the sensing device indicative of whether the other of said two switching devices is welded closed.

A third relay switches between an output of a first AC power source fed via a first relay and an output of a second AC power source fed via a second relay, and supplies the output after the switching to a load. A welding detection unit detects welding of the first relay. In order to switch the output of the first AC power source to the output of the second AC power source and supply the output of the second AC power source to the load, a power source switching control unit switches the first relay from the closed state to the open state, switches the third relay so as to select and feed the output of the second AC power source, and then prohibits switching of the second relay from the open state to the closed state until a first-relay welding detection processing by the welding detection unit is completed.

A system includes a relay system and a controller. The relay system includes a relay having a first contact on an input side of the relay, the input side coupled to a power source, and a second contact on a load side of the relay coupled to a load. The controller is configured to monitor a current flow from the power source through the relay, transmit a close signal to the relay, and to transmit an open signal to the relay. Based on the current flow through the relay following the open signal, determine whether an electrical weld of one of the first contact and the second contact of the relay exists.

A system includes a relay system and a controller. The relay system includes a plurality of relays, each having a first contact on an input side of the respective relay, the input side coupled to a power source, a second contact on a load side of the respective relay coupled to a load, and a spanner configured to close the first and second contacts of the respective relay when activated by a close signal. The load sides of each of the respective relays are coupled through their respective loads. The controller is configured to measure a voltage between a spanner of a first relay and an input side of a second relay. Based on the voltage between the spanner of the first relay and the input side of the second relay, the controller determines whether an electrical weld of one of the contacts of the first relay exists.

Contacts of a relay may glue together during operation. This state may be measured and a controller may issue a pulse width-modulated signal at a certain duty cycle and frequency in order to vibrate the relay contacts to make them open again. Once this is the case, the process is stopped. This process may be repeated a certain number of times, and if successfully degluing is not possible, a notification may be generated. Also after a certain number of degluing cycles, a signal may be generated to indicate replacement of the relay.

A method for cleaning electrical contacts of an electrical switching device includes displacing a first electrical contact element and a second electrical contact element of an electrical contact relative to each other so that the first electrical contact element and the second electrical contact element are in a closed position; and when the first and second electrical contact elements are in the closed position applying a waveform on the electrical contact so that the first contact element and the second contact element are excited to undergo a mechanical vibration relative to each other.

A load control device (e.g., a switching device) for controlling power delivered from an AC power source to an electrical device (e.g., a lighting load) may be configured to detect that a relay is stuck closed and attempt to fix the relay. The relay of the load control device may be adapted to be coupled between the source and the electrical device to control the power delivered to the electrical device so as to generate a switched-hot voltage. The load control device may comprise a detect circuit configured to generate a detect signal indicating a magnitude of the switched-hot voltage, and a control circuit configured to monitor the detect signal. The control circuit may be configured to determine that the relay is stuck closed in response to the detect signal, and to control the relay in order to attempt to fix the relay by repeatedly closing and opening the relay.

A load control device (e.g., a switching device) for controlling power delivered from an AC power source to an electrical device (e.g., a lighting load) may be configured to detect that a relay is stuck closed and attempt to fix the relay. The relay of the load control device may be adapted to be coupled between the source and the electrical device to control the power delivered to the electrical device so as to generate a switched-hot voltage. The load control device may comprise a detect circuit configured to generate a detect signal indicating a magnitude of the switched-hot voltage, and a control circuit configured to monitor the detect signal. The control circuit may be configured to determine that the relay is stuck closed in response to the detect signal, and to control the relay in order to attempt to fix the relay by repeatedly closing and opening the relay.