JP2007309237A - Hermetic electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hermetic electric compressor capable of positively displaying a protection function. <P>SOLUTION: The hermetic electric compressor is provided with an electric element, a compression element driven by the electric element, and a protection device 3 for protecting the electric element thereinside, and is equipped with a power supply circuit for supplying power source to the electric element. By providing an overcurrent fusing type element 5 on the outside of the hermetic container, which is not fused at a normal starting current value and is fused at a short circuit current value of the starting capacitor 4, and carries out fusion in a time shorter than the operation of the protection device 3, power supply is cut off. By exchanging the starting capacitor 4 and the overcurrent fusion type element 5, the hermetic electric compressor can be used thereafter without damaging other components. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

A hermetic electric compressor usually has some protective devices, but even in the case of a short circuit of a condenser, it can be protected by a compressor internal protective device or a circuit breaker (for example, patent documents). 1).
JP-A-2005-240596

  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. However, it was difficult to select, and the hermetic compressor had to be replaced despite the breakage of the protective device.

  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 at a current value larger than the starting current value of the hermetic electric compressor and below the current value when the starting capacitor is short-circuited.

  The overcurrent fusing type element is set so as to blow out in a time shorter than the operating time of the protection device for protecting the electric element when a short-circuit current due to a short circuit of the starting capacitor flows.

  The hermetic electric compressor according to the present invention protects the electric element while the overcurrent fusing type element melts at a current value larger than the normal starting current value when a short-circuit current due to a short-circuit of the starting capacitor flows. Since the overcurrent fusing type element is set to blow out in a shorter time than the time when the protective device operates, the power supply can be stopped by fusing, and then the compressor can be driven regardless of whether the power is turned on or off. In addition, the protective device for protecting the electric element can be safely stopped without repeating the operation. Further, the hermetic electric compressor can be individually protected regardless of the capacity of the circuit breaker set in the normal power supply circuit.

For this reason, the capacitor can be used by simply replacing the starting capacitor with a new one without damaging other components due to the occurrence of a capacitor short circuit such as a short circuit of the starting capacitor.

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

(Embodiment 1)
FIG. 1 shows an 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. The overcurrent fusing type element 5 having a fuse function 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 short-circuit current due to a short-circuit of the starting capacitor flows. Specifically, this setting uses a copper-based alloy and changes the length, width, height or cross-sectional area and length of the fuse part of the part to be melted. By setting, the target fusing current and time are adjusted.

  In the hermetic electric compressor, when the capacitor is short-circuited for some reason, a current about 1.5 times the compressor starting current flows, and the protective device for protecting 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 the compressor starting current flows continuously, and eventually the electric element burns out, causing a short circuit, and from 1.5 times the compressor starting current. In addition, a large current flows, and there is a high possibility of developing into accidents such as pin jumping and wiring burnout.

  However, in the hermetic electric compressor according to the present invention, when a short current due to a short-circuit of the starting capacitor flows, the overcurrent fusing type element is blown out in a time shorter than the operating time of the protective device for protecting the electric element. Since it is set, it cuts off the power supply itself by fusing, and since the power supply is stopped by fusing, the protection device that protects the electric element can be stopped safely without repeating the operation thereafter .

  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, It is not perfect in terms of compressor protection. 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 safely stop the compressor against a short-circuit of the starting capacitor, and the compressor can be used again only by replacing some parts. Therefore, it can be applied not only to air conditioners and refrigerators but also to water heaters and dehumidifiers using heat pumps.

Connection diagram of hermetic electric compressor in one embodiment of the present invention Connection diagram of a conventional hermetic electric compressor

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 A hermetic electric compressor in which an overcurrent fusing type element that blows when a current larger than a starting current value flows in the electric element is provided outside the hermetic container. 2. The hermetic electric compressor according to claim 1, wherein the overcurrent fusing type element is blown at a current value larger than a starting current value of the hermetic electric compressor and not more than a current value when the starting capacitor is short-circuited. 2. The hermetic electric compressor according to claim 1, wherein the overcurrent fusing type element is blown in a time shorter than a time in which a protection device for protecting the electric element operates when a short current due to a short circuit of the starting capacitor flows.

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