JP2008002345A - Hermetically-sealed type electromotive compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hermetically-sealed type electromotive compressor in which a protection function can be exercised without fail. <P>SOLUTION: There is provided a hermetically-sealed electromotive compressor which is provided with an electromotive element, a compressive element driven by the electromotive element, and a protection device for protecting the electromotive element in a hermetically-sealed container and further is equipped with a power supply circuit for supplying electric power to the electromotive element. In the hermetically-sealed electromotive compressor, there is installed an overcurrent-meltdown-type element which is melted down over a shorter amount of time than that required for a start of the protection device for protecting the electromotive element as well as being melted down by an even larger current than a short-circuit current value that is larger than a starting current value at normal times and is caused by a short circuit of a starting capacitor and thereby the power supply itself is shut down. Therefore, without relation to subsequent turn-on and -off operations, without driving the compressor and further without an iterative operation of the protection device for protecting the electromotive element, the electromotive element can be safely stopped, thus permitting the hermetically-sealed electromotive compressor to be independently protected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hermetic type electric compressor used for refrigeration equipment such as an air conditioner and a refrigerator.

Sealed electric compressors usually have some protective devices, but they may not be able to fully protect against abnormal situations such as motor burnout. There is a method of providing multiple protection devices (see, for example, Patent Document 1).
JP 2005-240596 A

  However, even with the above-mentioned method, it may not function due to incomplete grounding treatment or contact welding of the magnetic switch, etc., leading to damage to the compressor power supply terminal (so-called pin jumping), or accidental burnout of wiring or mounted unit It may be possible to develop up to In addition, for protection by internal protection devices, it has been proposed that the protection device is repeatedly opened and closed, which eventually shuts off the power supply, but it is installed inside the compressor and affects the normal protection characteristics. It was difficult to select.

  The present invention provides a hermetic electric compressor capable of reliably exhibiting a protective function.

  The present invention includes an electric element housed in an airtight container, a compression element driven by the electric element, and a protection device for protecting the electric element, and a power supply circuit for supplying power to the electric element is provided outside. In the hermetic electric compressor provided, an overcurrent fusing type element having a characteristic of fusing when a current larger than a starting current value flows through the electric element is provided outside the hermetic container.

  The overcurrent fusing type element is set so as to blow when the current value is larger than the starting current value of the hermetic electric compressor and is equal to or greater than the current value when the starting capacitor is short-circuited.

  The overcurrent fusing type element operates a protection device that protects the electric element when a current larger than the starting current value of the hermetic electric compressor and larger than the short-circuit current value due to a short circuit of the starting capacitor flows. It is set so as to blow in a time shorter than the time.

  According to the present invention, in a hermetic type electric compressor, when a current larger than a short-circuit current due to a start current or a short-circuit of a start capacitor flows, an overcurrent fusing type element is blown and a protection device that protects an electric element operates. Since the overcurrent fusing type element is set to blow out in a time shorter than the time, it cuts off the power supply itself by fusing, and the power supply can be stopped by fusing. It can be safely stopped without driving the compressor and without repeating the operation of the protective device for protecting the electric element. Further, the hermetic electric compressor can be individually protected regardless of the capacity of the circuit breaker set in the normal power supply circuit.

  Hereinafter, embodiments will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a first embodiment of the present invention. The hermetic electric compressor (not shown) of the present invention includes an electric element (a so-called motor, not shown) and a compression element (not shown) driven by the electric element in a hermetic container (not shown). A power supply circuit (not shown) is provided outside the sealed container for supplying power to the electric element. The electric element includes a stator (not shown) and a rotor (not shown). Reference numeral 1 denotes a main winding of the stator and 2 denotes an auxiliary winding of the stator. Reference numeral 3 denotes a protective device for protecting the electric element in the sealed container attached to the common line. A starting capacitor 4 is provided between the auxiliary winding 2 and the power source. A fuse function (overcurrent fusing type element) 5 is attached to each common line.

  This fuse function is set so as to have a characteristic of fusing in a shorter time than the operation time of the protection device for protecting the electric element when a current larger than a short circuit current due to a short circuit of the starting capacitor flows. Specifically, the characteristics change by using a copper-based alloy and changing the length, width, and height (or cross-sectional area and length) of the fuse part to be melted. By setting this dimension, the target fusing current and time are adjusted.

  In the hermetic electric compressor, when a state in which the compressor cannot rotate with the compression element occurs, a starting current flows. When the capacitor is short-circuited for some reason, a current about 1.5 times the compressor starting current flows. In either case, a protection device that protects the electric element operates. After the operation, the protection device will eventually return, the current will flow again, and this operation will be repeated. Eventually, the protection device reaches the end of its life and reaches the end of its life in an energized state or a released state. In the released state, the power is not turned on at that time, the current is cut off, and it is protected safely. However, when it reaches the end of its life in an energized state, a current of about 1.5 times or more of the compressor starting current flows continuously, and eventually the electric element burns out, causing a short circuit, and 1.5 times the compressor starting current. Larger current flows and there is a high risk of developing into accidents such as pin jumping and wiring burnout.

  However, in the hermetic electric compressor of the present invention, when a short-circuit current due to a short-circuit of the starting current or the starting capacitor flows, the overcurrent fusing type element is blown out in a time shorter than the operation time of the protective device protecting the electric element. Since the power supply itself is cut off by fusing and the power supply is stopped by fusing, the protective device that protects the electric elements does not repeat the operation and is safe. Can be stopped.

  In addition, a circuit breaker is usually installed in the power supply circuit, but this capacity is determined not only considering the starting current value of the hermetic electric compressor but also considering the current of the entire system, The protection aspect of the compressor is not perfect. In the present invention, the hermetic electric compressor can be individually protected.

  As described above, the hermetic electric compressor according to the present invention can stop the power supply by fusing, and then the protective device for protecting the electric element operates without driving the compressor regardless of whether the power is turned on or off. You can safely stop without repeating. In addition, the sealed electric compressor can be individually protected regardless of the capacity of the circuit breaker set in the normal power supply circuit, so that it can be applied to applications such as a dehumidifier and a heat pump type water heater.

The figure which shows the Example of this invention Conventional configuration diagram

Explanation of symbols

3 Protection device for protecting electric elements 4 Capacitor for starting 5 Overcurrent fusing type element

Claims (3)

A hermetic electric compressor including therein an electric element housed in a hermetic container, a compression element driven by the electric element, a power supply circuit for supplying power to the electric element, and a protection device for protecting the electric element The closed type electric compressor is characterized in that an overcurrent fusing type element having a characteristic of fusing when a current larger than a starting current value flows through the electric element is provided outside the closed vessel. 2. The hermetic electric compressor according to claim 1, wherein the overcurrent blown-type element is set so as to blow at a current value equal to or greater than a current value when a starting capacitor is short-circuited. The overcurrent fusing type element is larger than the starting current value of the hermetic electric compressor, and when a current larger than the short-circuit current value due to the short-circuit of the starting capacitor flows, the overcurrent operating time of the protection device that protects the electric element A hermetic electric compressor that is set to melt in a short time.

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