摘要:
A back-up uninterruptible power system has a power supply path from input terminals connected to AC power system lines to normally supply power to a load. Upon the occurrence of a line fault, a static switch in the power supply path interrupts the connection between the AC power lines and the load and an inverter is turned on to provide power derived from an auxiliary battery through a transformer to the power supply path to supply AC power to the load. By using the static switch, switching from line connection to backup power can be done quickly, within a half cycle, so that substantially no interruption of the output waveform is observed. The inverter can be operated to provide a commutation pulse to the SCRs in the static switch to commutate an SCR which might otherwise continue conducting after the triggering signals to the gates are cut off and before the inverter supplies the AC power to the load. A relay connected between the input terminals and the static switch is controlled to open relay contacts after the static switch has interrupted the current flow to the load, thereby providing positive electrical isolation of the AC power system from the uninterruptible power system while allowing the mechanical relay contacts to switch only during times of no current. Line fault detection is carried out by creating a digital waveform composed of an average of prior cycles of the AC input waveform, converting the stored waveform to an analog signal, and comparing it with the present input signal in phase lock therewith to detect deviation of the input signal from the reference waveform.
摘要:
A beverage dispensing system includes a beverage dispenser which forms and dispenses a beverage and a processor for monitoring the beverage dispenser. The beverage dispenser operates under various parameters including a first parameter that is indicative of the quality of the beverage to be dispensed and a second parameter that is indicative as to when routine maintenance is to be scheduled. The processor monitors the various parameters under which the beverage dispenser operates and determines whether the first parameter is outside of a predetermined range. If the first parameter is outside the predetermined range, the processor sends a signal regarding a request for immediate repair service. The second parameter is also monitored and the routine maintenance is scheduled based thereon.
摘要:
AC line monitoring is provided for uninterruptible power supplies to detect AC power system line faults by comparing the presently received cycle of the AC power line signal with a reference waveform. The reference waveform is formed of a composite of waveforms from prior cycles which adapts over time to the shape of the AC power line waveform, so that waveforms other than pure sinusoids can be accepted without triggering false fault conditions. The composite reference waveform may be formed of essentially all samples from prior cycles with exponentially decaying weighting. An excessive deviation of the current waveform from the reference waveform results in a fault being detected which causes switching of the uninterrupible power supply to provide backup power. The RMS value of the power line voltage is also estimated on a substantially real time basis, preferably by calculating the RMS value of the reference waveform, to provide a fault condition signal when the estimated RMS value falls below a selected level, which also can be utilized to cause switching of the uninterruptible power supply.
摘要:
The inverter of an uninterruptible power system is tested by turning on switches in the inverter at a selected test phase in each half-cycle of the AC input waveform so that the inverter provides a voltage which opposes the AC input voltage waveform during part of each half-cycle of the waveform. The resulting current drawn from the inverter battery, if any, is measured and its peak may be found. The peak battery current during each half-cycle is compared to maximum allowable peak currents to determine if an inverter failure has occurred. If the peak currents are lower than a maximum acceptable value, the test is repeated on a subsequent AC input waveform at a decreased test phase (a shorter time delay from the zero crossing of each half-cycle of the waveform) until the peak current in the first half-cycle is at a selected value, at which time the peak in the second half-cycle is checked to determine if it is within an acceptable range. If not, an inverter test failure is indicated. Inverter test failure is also indicated if repeated cycles during which the test phase is reduced fail to cause the first peak to reach the proper value and the test phase is finally reduced to a minimum allowable test phase. If the inverter has been tested and is found to be operating properly, a battery test can be conducted by selectively disconnecting the AC power system from the load, turning on the inverter for a selected period of time, and detrmining remaining available run time based on the battery voltage while the inverter was running.
摘要:
A method and means for programming the operation of an apparatus having at least a plurality of different control functions provides a control panel, an arrangement for causing the control panel to appear blank prior to initial activation of the apparatus, circuitry for initially activating the apparatus, and circuitry responsive to initial activation for indicating and allowing selection of the different control functions, the circuitry for indicating and allowing selection including circuitry for sequentially displaying the control functions on the control panel to allow selection thereof.
摘要:
A pest control device system includes a plurality of pest control devices and a data collector. The system may further include the data collector in the form of a gateway that is connected to a data management server via a computer network along with other gateways in corresponding pest control device groups. Each pest control device includes a pest sensor and a wireless communication circuit to transmit information from the corresponding sensor. The devices also configure to define a local wireless communication network that can relay the information from one to the next and ultimately to the data collector.
摘要:
As a rotary member is rotated, light images are produced in a radial direction from the rotary member. The light images are produced in time or position division multiplexed fashion so that, although at any given instant, only a portion of an entire image is actually generated, due to the light persistence of an observer's eye, the observer will observe an entire image about the rotary member.
摘要:
A pest control device system includes a plurality of pest control devices and a data collector. The system may further include the data collector in the form of a gateway that is connected to a data management server via a computer network along with other gateways in corresponding pest control device groups. Each pest control device includes a pest sensor and a wireless communication circuit to transmit information from the corresponding sensor. The devices also configure to define a local wireless communication network that can relay the information from one to the next and ultimately to the data collector.
摘要:
A method and apparatus are disclosed for use with a battery powered inverter for powering a load through a ferroresonant transformer. The current flow through the inverter-ferroresorant transformer is sensed and is utilized to modulate the inverter's pulse width at a point, after a peak voltage but before saturation begins, when the slope of the inverter-ferroresonant transformer current with respect to time is at or near zero. A maximum current limiting feature can be provided in the method and apparatus of the present invention.