Patent classifications
H02P3/06
Pinch detection based on motor current increase
The pinch detector is suitable to detect a pinch at a closing member actuated by a motor equipped with a measuring circuit to measure a motor current. It includes a first portion that, when the motor starts closing the member, obtains a reference value of the motor current measured at the end of a blind time period having a predetermined duration from the moment the motor starts to close the member; a second portion that compares current values of the measured motor current to a threshold value depending on said reference value, during a detection time period, following the blind time period and preceding a steady state time period of the motor, in order to detect a pinch at the closing member based on a comparison result.
Pinch detection based on motor current increase
The pinch detector is suitable to detect a pinch at a closing member actuated by a motor equipped with a measuring circuit to measure a motor current. It includes a first portion that, when the motor starts closing the member, obtains a reference value of the motor current measured at the end of a blind time period having a predetermined duration from the moment the motor starts to close the member; a second portion that compares current values of the measured motor current to a threshold value depending on said reference value, during a detection time period, following the blind time period and preceding a steady state time period of the motor, in order to detect a pinch at the closing member based on a comparison result.
Elevator
The invention relates to an elevator comprising at least one elevator car moved by at least one elevator motor, which elevator motor is driven by a frequency converter controlled by a control device of the elevator, the frequency converter comprising a rectifier bridge, an inverter bridge and a DC link connected in-between, the inverter bridge being connected to the elevator motor and the rectifier bridge being connected to AC mains via three phase supply lines comprising an LCL-filter and a mains switch. The elevator further comprises a backup power supply and a safety device of the control device, which in case of a mains power failure is configured to switch off the mains switch and to connect the backup power supply to the DC link and/or to at least one phase supply line, whereby the rectifier bridge is a bidirectional rectifier bridge being configured to convert DC supplied to the DC link from the backup power supply to an AC voltage supplied to at least two of the phase supply lines connected with at least one load circuit. An earth fault protection circuit for the load circuit is connected between earth and a common terminal of the capacitors of the LCL filter for monitoring an earth fault indicating signal, and which earth fault protection circuit is configured to issue an earth fault signal and/or initiating earth fault safety measures, dependent on the earth fault indicating signal.
Elevator
The invention relates to an elevator comprising at least one elevator car moved by at least one elevator motor, which elevator motor is driven by a frequency converter controlled by a control device of the elevator, the frequency converter comprising a rectifier bridge, an inverter bridge and a DC link connected in-between, the inverter bridge being connected to the elevator motor and the rectifier bridge being connected to AC mains via three phase supply lines comprising an LCL-filter and a mains switch. The elevator further comprises a backup power supply and a safety device of the control device, which in case of a mains power failure is configured to switch off the mains switch and to connect the backup power supply to the DC link and/or to at least one phase supply line, whereby the rectifier bridge is a bidirectional rectifier bridge being configured to convert DC supplied to the DC link from the backup power supply to an AC voltage supplied to at least two of the phase supply lines connected with at least one load circuit. An earth fault protection circuit for the load circuit is connected between earth and a common terminal of the capacitors of the LCL filter for monitoring an earth fault indicating signal, and which earth fault protection circuit is configured to issue an earth fault signal and/or initiating earth fault safety measures, dependent on the earth fault indicating signal.
BRAKING RESISTOR ARRANGEMENT IN A COMPUTED TOMOGRAPHY GANTRY
A gantry for a computed tomography device has a support structure, a pivot bearing, a rotating frame, a first braking resistor configured to electromotively brake a rotational movement of the rotating frame, and a heat conductor configured to dissipate heat from the first braking resistor. A heat conductor and a pressure duct wall are interconnected to form a heat-conductor-to-pressure-duct-wall connection that is detachable, form-fitting, planar, and thermally conductive. The heat is transferrable from the first braking resistor to the airflow via the heat conductor, the heat-conductor-to-pressure-duct-wall connection and the pressure duct wall.
BRAKING RESISTOR ARRANGEMENT IN A COMPUTED TOMOGRAPHY GANTRY
A gantry for a computed tomography device has a support structure, a pivot bearing, a rotating frame, a first braking resistor configured to electromotively brake a rotational movement of the rotating frame, and a heat conductor configured to dissipate heat from the first braking resistor. A heat conductor and a pressure duct wall are interconnected to form a heat-conductor-to-pressure-duct-wall connection that is detachable, form-fitting, planar, and thermally conductive. The heat is transferrable from the first braking resistor to the airflow via the heat conductor, the heat-conductor-to-pressure-duct-wall connection and the pressure duct wall.
METHOD AND DEVICE FOR MONITORING SWITCHGEARS
A method for monitoring switchgear, provided with a switching mechanism, including: monitoring an electric power supply signal to an electromagnetic actuator of the switching mechanism in order to detect the start of the supply of electric power to the actuator, monitoring an impact intensity measurement in the switchgear in order to detect the setting in motion of the switching mechanism, monitoring a parameter representative of the open or closed state of the switchgear in order to detect a change in state of the parameter, representative of an end of an opening or closing sequence of the switchgear.
The method further includes: calculating a time T.sub.ACT that has elapsed between the detection of the start of the supply of electric power to the actuator and the detection of the setting in motion of the switching mechanism of the switchgear, calculating a time T.sub.M that has elapsed between the setting in motion of the switching mechanism and the sequence end.
Electrical architecture for an aircraft, aircraft comprising the architecture and method for operating the architecture
An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.
Electrical architecture for an aircraft, aircraft comprising the architecture and method for operating the architecture
An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.
UNDER-SPEED AND CLOSED-LOOP SPEED CONTROL IN A VARIABLE-SPEED POWER TOOL
A method of operating a power tool having a motor and a controller is provided. The method includes: receiving a position of a variable-speed input mechanism mounted on the power tool; determining a target speed of the motor corresponding to the position of the variable-speed input mechanism; determining an underspeed threshold corresponding to the target speed; determining a rotational speed of the motor; and interrupting a supply of power to the motor if the rotational speed of the motor is less than the underspeed threshold.