摘要:
An active noise cancelling apparatus for actively controlling noise generated by a compressor, where noise is apt to externally leak from an opening portion of a machine chamber storing the compressor driven by an A.C. power supply. The active noise cancelling apparatus includes: a microphone, provided in the vicinity of the opening portion, for detecting noise generated by the compressor; fundamental wave component extracting portion for extracting a fundamental wave component of rotation frequency of the compressor, from a sound signal of the noise detected by the microphone; periodic signal generating circuit for a periodic signal correlative to the fundamental wave component extracted by the fundamental wave component extracting portion; periodic signal outputting circuit for outputting a predetermined periodic signal by means of comparing a phase of the periodic signal generated by the periodic signal generating circuit with a phase of the fundamental wave component; uncancelled sound extracting portion for extracting noise having been not cancelled, excluding the fundamental wave component; sound source waveform generating circuit for forming a harmonics component from the signal outputted by the fundamental wave component extracting circuit; control signal generating circuit for correcting a control signal outputted from the sound source waveform generating circuit, based on a signal from the uncancelled sound extracting portion and for generating the corrected signal in a feedback manner; and a loudspeaker for outputting the control signal generated from the control signal correcting circuit.
摘要:
An active noise attenuating device applied to a draft duct of an air condition system including a microphone disposed in a propagation path of noise for detecting the noise, a loud speaker disposed in the noise propagation path, a control circuit for producing a control signal on the basis of the detection signal from the microphone, the control signal being supplied to the loud speaker so that the speaker produces an interference sound having the same amplitude as of the noise detected by the microphone and a phase opposite to the noise, at a control point in the noise propagation path, and a high pass filter for damping or cutting off a frequency component contained in the control signal and belonging to a low frequency range in which the loud speaker is unable to reproduce the interference sound.
摘要:
An active noise attenuating device includes a first microphone located in a propagation path of noise, a loud speaker located downstream from the first microphone, a second microphone located downstream from the loud speaker for receiving sound, and an operational unit for executing an operation on the basis of a detection signal from the first microphone to generate a control signal supplied to the loud speaker so that a sound interfering with the noise is produced. An operational factor of the operational unit is controlled by an adaptive controller on the basis of the detection signal from the second microphone so that an amount of noise attenuated by the sound produced from the loud speaker is rendered maximum. A transfer characteristic of a transfer path between the loud speaker and the second microphone is identified on the basis of the detection signals generated by the second microphone when a sound represented by a periodical identifying signal is produced in a plurality of periods. An operational factor of the adaptive controller is adjusted by an adaptive control identifying unit on the basis of the identified transfer characteristic.
摘要:
An apparatus includes an electro-acoustic converter, a detector, a noise correlative signal generator, and an additional tone signal generator in order to actively control noise generated by an electromagnetic machine, which noise is apt to externally leak from an opening of a machine room storing the electromagnetic machine driven by an AC power supply. The electro-acoustic converter applies a predetermined sound wave to the opening of the machine room. The detector essentially detects a frequency of an AC voltage waveform to be applied to the electromagnetic machine driven by the AC power supply. The noise correlative signal generator generates generating a signal correlative with an electromagnetic noise component included in noise generated by the electromagnetic machine according to a detection signal from the detector. The additional tone signal generator generates, according to an output signal from the noise correlative signal generator, an additional tone signal for causing the electro-acoustic converter to apply a sound wave essentially having a phase opposite to and the same amplitude as those of the electromagnetic noise component at the opening of the machine room.
摘要:
A refrigerator has a refrigerating cycle sequentially connecting a compressor, a condenser, a drawing mechanism, and evaporator, an accumulator, an inlet temperature sensor and an outlet temperature sensor for detecting the temperatures of the inlet and outlet of the evaporator, and a cooling fan for cooling the compressor. When the difference between the temperature detected by the inlet temperature sensor and the temperature detected by the outlet temperature sensor is a predetermined value or more, the cooling fan is stopped.
摘要:
An adaptive type active noise cancellation apparatus comprises a first sensor for detecting a noise generated by a noise source and outputting a detection signal, a filter having a predetermined filter coefficient and filtering the output signal from the first sensor by using the predetermined filter coefficient and outputting a filtered signal, a speaker for receiving the filtered signal and generating a sound corresponding to the filtered signal, an active noise cancellation control system for actively canceling a noise at a control target point by using the sound generated by the speaker, a second sensor, arranged at the control target point, for detecting a sound at the control target point and outputting a detection signal, and an adaptive control system for receiving the output signals from the first and second sensors and adaptively updating the filter coefficient in accordance with a change in state of a system to which the active noise cancellation control system is applied. The adaptive control system includes a switch for stopping the active noise cancellation control system in adaptive processing, and a correction system for correcting the output signal from the first sensor or the second sensor by using a transfer function corresponding to a delay in a spatial system between the speaker and the second sensor and a delay required for calculation processing.
摘要:
A refrigerator has a refrigerating cycle sequentially connecting a compressor, a condenser, a drawing mechanism, and evaporator, an accumulator, an inlet temperature sensor and an outlet temperature sensor for detecting the temperatures of the inlet and outlet of the evaporator, and a cooling fan for cooling the compressor. When the difference between the temperature detected by the inlet temperature sensor and the temperature detected by the outlet temperature sensor is a predetermined value or more, the cooling fan is stopped.
摘要:
A refrigerator of the present invention includes a refrigerating cycle including a compressor, a condenser, an expander and an evaporator and filled with a flammable refrigerant, a load detector detecting a change in load of the compressor, and a control device detecting a damage which is a cause for leak of the refrigerant from the refrigerating cycle, based on a detection output of the load detector.
摘要:
A refrigerator includes a refrigerating cycle unit for refrigerating an atmosphere in the refrigerator by means of heat absorption due to change of a flammable refrigerant from a liquid phase to a gaseous phase, and a deodorizer having first and second electrodes discharging electricity upon application of high voltage to them, producing ozone, a burning chamber provided so as to surround the first and second electrodes, and a fire-spread preventing unit provided in the burning chamber to prevent burning of the flammable refrigerant in the burning chamber from spreading outside the burning chamber.
摘要:
A refrigerator-freezer is described, in which refrigerant leakage from the refrigeration cycle can be safely detected. The refrigerator-freezer comprises: a refrigeration cycle formed by a compressor, a capillary, an evaporator and an accumulator connected in series, and filled with a flammable refrigerant; a cooling fan configured to blow the cold air cooled by the evaporator in the refrigerator-freezer; and a refrigerant leakage detection system configured to detect leakage of the flammable refrigerant, wherein the refrigerant leakage detection system is provided with a temperature sensor configured to measure the temperature of a refrigerant conduit of the evaporator and judges that the flammable refrigerant is leaking in the low pressure side of the refrigeration cycle when the temperature is detected by the temperature sensor with the compressor being halted is no lower than a predetermined temperature.