An abnormality detection circuit includes an AC power source coupled to a load via first and second wiring lines, a first relay contact disposed in the middle of the first wiring line, a second relay contact disposed in the middle of the second wiring line, a comparative voltage detection circuit to which a voltage is applied from the AC power source irrespective of whether the first and second relay contacts are open or closed, a first voltage detection circuit to which a voltage is applied from the AC power source when the first relay contact is closed, a second voltage detection circuit to which a voltage is applied from the AC power source when the second relay contact is closed, and an abnormality detector that detects abnormalities of the first relay contact by comparing the voltage applied to the comparative voltage detection circuit with the voltage applied to the first voltage detection circuit and detects abnormalities of the second relay contact by comparing the voltage applied to the comparative voltage detection circuit with the voltage applied to the second voltage detection circuit.

An image forming system comprises a first housing, a second housing and a third housing. The second housing may comprise a motor, a first door and a first switch. The first switch is provided on an electrical path connecting a power supply and the motor, for switching between a first state and a second state and for switching from the first state to the second state. The third housing may comprise a load. When the first door is opened in a state where the first switch is in the first state, the first switch switches from the first state to the second state to cause supply of electric power to the load to be cut off.

The disclosure relates to a method for predicting the failure of an elementary relay having a switch for switching a load contact of a load circuit and an excitation coil for actuating the switch. The method may include exciting the excitation coil in order to switch on the load contact; detecting a time characteristic of a contact voltage at the load contact when switching on the load contact; extracting a characteristic feature from the time characteristic of the contact voltage; and monitoring the characteristic feature during operation of the elementary relay.

Provided is a circuit assembly including: a main relay that is to be electrically connected between a load and a battery; a pre-charge circuit connected in parallel with the main relay; and a heat transfer member, wherein the pre-charge circuit includes current-carrying portions that are to be connected to the main relay, and the heat transfer member and the current-carrying portions are in contact with each other.

Provided is a circuit assembly including: a main relay that is to be electrically connected between a load and a battery; a pre-charge circuit connected in parallel with the main relay; and a heat transfer member, wherein the pre-charge circuit includes current-carrying portions that are to be connected to the main relay, and the heat transfer member and the current-carrying portions are in contact with each other.

A relay fault diagnosis device includes: at least one C-contact relay that has a common terminal, a normally open terminal and a normally closed terminal; a read-back circuit that is connected to the normally closed terminal of the relay; and a diagnostic section that outputs a test signal to the common terminal to diagnose a fault in the relay.

A power accumulation system includes a power accumulation device, a relay device provided in a pair of power lines disposed between the power accumulation device and a power conversion device that exchanges power with the power accumulation device, a capacitor provided between the pair of power lines between the relay device and the power conversion device and an electronic control device that controls the relay device. The electronic control device is configured to execute a predetermined foreign matter removal process when it is not possible to bring one of a first relay and a second relay from a power blocking state to a conductive state.

The invention relates to a safety-related switching device (10) which is equipped with an electromagnetic coil (12), a control unit (20) and a first switching means (22). The first switching means (22) is designed to activate and deactivate the electromagnetic coil (12). Moreover, the first switching means (22) is designed to receive a coil control signal (24), a monitoring signal (32) and a first higher-level control signal (26). The safety-related switching device (10) also has a receiver unit (40) for receiving an external control signal (29). The receiver unit (40) is designed to generate the first higher-level control signal (26) and a second higher-level control signal (28) from the external control signal (29). The control unit (20) is designed to receive the second higher-level control signal (28).

The present invention relates to a power supply circuit (400) for a breaking circuit (100), the power supply circuit (400) comprising a first connecting point (CP1) arranged to be connected to an input (102) of the breaking circuit (100) and a second connecting point (CP2) arranged to be connected to an output (104) of the breaking circuit (100). The power supply circuit (400) further comprises a first rectifier (416) and a second rectifier (418) connected in series and in opposite direction to each other between the first connecting point (CP1) and the second connecting point (CP2); a first switch (412) and a second switch (414) connected in series between the first connecting point (CP1) and the second connecting point (CP2), wherein the first switch (412) and the second switch (414) are connected in parallel to the first rectifier (416) and the second rectifier (418); and a first capacitor (C1) having a first connecting point (CP1.sub.C1) connected between the first rectifier (416) and the second rectifier (418) and a second connecting point (CP2.sub.C1) connected between the first switch (412) and the second switch (414), wherein the first connecting point (CP1.sub.C1) of the first capacitor (C1) is further arranged to be connected to a power consumer (110a, 110b, . . . , 110n) of the breaking circuit (100). The power supply circuit (400) is arranged to at least one of: open the first switch (412) so that a current running from the input (102) to the output (104) passes via the first rectifier (416), the first capacitor (C1) and the second switch (414) thereby charging the first capacitor (C1); and open the second switch (414) so that a current running from the output (104) to the input (102) passes via the second rectifier (418), the first capacitor (C1) and the first switch (412) thereby charging the first capacitor (C1).

A system may include a relay device that includes armatures associated with phases of voltage signals. The system may also include relay coils, such that each relay coil may receive a respective voltage that magnetizes a respective relay coil, thereby causing the respective armature to move from a respective first position to a respective second position. The system may also include a control system that receive an indication that a fault condition is present, identify a first phase of the phases of voltage signals that is expected to be the next phase of the phases to cross zero, and send a signal to the relay device in response to identifying the first phase. The signal is configured to cause a first relay coil of the relay coils to energize or deenergize.