Abstract:
The disclosure relates to a method of detecting and managing voltage instability in power systems operations. The disclosed method identifies and follows Thevenin and load impedance values as they fluctuate in a power system using synchrophasor measurements. The values are recursively estimated and entered into calculations to identify stability margins through a simple P-Q plane representation to determine if load shedding is necessary.
Abstract:
A hybrid fire suppression system includes a supply of pressurized inert gas, a pipe network connected in inert gas flow communication to the inert gas supply, a first inert gas nozzle, a second inert gas nozzle, and a water storage cartridge having an interior volume defining a water reservoir storing a limited amount of water. The water reservoir communicates with the second inert gas spray nozzle. The first inert gas nozzle connects with the first terminus for introducing a flooding flow of inert gas only into a first protected space. The second inert gas nozzle connects with the second terminus for introducing a flooding flow of inert gas and the limited amount of water from the water reservoir into the second protected space.
Abstract:
An electromagnetic door lock assembly (30) includes a first portion (32) supported relative to hoistway doors (22) and a second portion (34) supported for movement with an elevator car (24). The first and second portions cooperate so that electromagnetic interaction between them unlocks a set of hoistway doors (22) for access to the car (24), for example. In disclosed embodiments, a first portion (32) of the actuator has at least one stationary electromagnetic portion (36A, 36B) and at least one moveable portion (38). The second portion (34) that moves with the car (24) includes at least one stationary electromagnetic portion (44). Magnetic interaction between the first and second portions (32, 34) causes selected movement of the moveable portion (38) for selectively locking or unlocking the doors (22).
Abstract:
An elevator door assembly (20) includes a single vane member (32) associated with a hoistway door (26). A magnetic device (36) on a car door (24) establishes a magnetic coupling with the vane member (32) to cause the hoistway door (26) to move with the car door (24) in at least two opposite directions. In a disclosed embodiment, a control (38) selectively powers the magnetic device (36), which comprises an electromagnet.
Abstract:
An oxygen measuring apparatus (500) includes an inlet pipe (506) having a first end and a second end, an oxygen sensor (511) arranged inside the inlet pipe (506) between the first end of the inlet pipe and the second end of the inlet pipe, the oxygen sensor (511) having a communication medium (515) disposed thereon and extending through the second end of the inlet pipe (506), a filtering medium arranged (505) inside the inlet pipe between the oxygen sensor (511) and the first end of the inlet pipe, a housing (501) arranged against the second end of the inlet pipe, and a sensor control interface (512) arranged within the housing (501) and in communication with the communication medium (515) of the oxygen sensor (511).
Abstract:
A self-regulating valve controls the flow of high pressure gas discharging from a gas cylinder in a fire suppression system in response to a detection of a fire within a protected space by a two-step process which reduces the pressure rise within the protected space upon release of the fire suppression gas into the protected space.
Abstract:
A method is provided for tuning an oxygen trim controller during the commissioning of a combustion control system for controlling operation of a boiler combustion system, rather than tuning the oxygen trim controller after the commissioning process has been completed.
Abstract:
An elevator door lock assembly (30) includes a sensor device (40) for providing an indication of a properly locked door. A plurality of proximity sensor elements (42, 44) interact with activating elements (52, 54) when the door lock assembly (30) is properly locked. In disclosed examples, a specific geometric pattern of the sensor elements (42, 44) and the activating elements (52, 54) provides redundancy and tampering protection. In a disclosed example, an output from the sensor device (40) provides an indication of a condition of the door lock and a building level location of a plurality of sensor devices.
Abstract:
An exemplary method of communicating with a safety device includes obtaining a key from the safety device that is useable for only a single communication session with the safety device. A plurality of messages are sent to the safety device during the single communication session. Each of the plurality of messages includes the obtained key, an identifier of the source of the message, an identifier of the safety device, a sequence number indicating how many of the plurality of messages preceded the message during the communication session, a command for the safety device, and at least one cyclic redundancy code (CRC) based on content of the message. A next one of the plurality of messages is sent only after confirming that the safety device has accepted a most recently sent one of the plurality of messages.
Abstract:
A method is provided for commissioning a combustion control system for controlling operation of a boiler combustion system. The method includes the step of mapping a plurality of sets of coordinated servo positions for the fuel flow control device and the air flow control device at a plurality of selected firing rate points between a minimum firing rate and a maximum firing rate by using an algorithm and an iterative process to identify the coordinated air and fuel actuator positions instead of a trial and error method.