JP3391135B2 - Overload protection device for hermetic electric compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overload protection device for a hermetic electric compressor. 2. Description of the Related Art A conventional hermetic electric compressor overload protection device for an air conditioner will be described with reference to the drawings. [0005] In FIG. 5, reference numeral 101 denotes a hermetic electric compressor in which an electric element and a compression element are arranged inside a closed container.
A motor 02 is an electric element. A power terminal 103 and an overload protection device 10 are provided around the hermetic compressor 102.
4 is attached by a terminal cover 105. In FIG. 6, a motor 102 has a main winding 10.
2a, an auxiliary winding 102b and a rotor (not shown). Reference numeral 104 denotes an overload protection device comprising a normally closed bimetal 104a. The motor 102 is connected to an AC power supply 106, a driving capacitor 107, and the overload protection device 104. The operation of the above configuration will be described. When the AC power supply 106 is turned on, current flows through the motor 102, the overload protection device 104, and the operation condenser 107, and the hermetic electric compressor 101 enters a steady operation state. However, during operation of the hermetic electric compressor 101, for example, an overload state occurs and the hermetic electric compressor 101 has an overcurrent or an abnormal temperature in the outer shell, and the hermetic electric compressor 10
The bimetal 104a of the overload protection device 104 attached to the outer shell 1 is thermally deformed and inverted to cut off the current to the motor 102 and stop the operation of the hermetic electric compressor 101. However, in the conventional overload protection device for a hermetic electric compressor, since only one bimetal is used, a prescribed amount of refrigerant is sealed in the air conditioner and the overload condition is caused. When this happens, the hermetic electric compressor can be protected to some extent.However, when the amount of refrigerant is less than the specified refrigerant amount or when the voltage is low, the current flowing through the hermetic electric compressor is small, so the overload protection device operates. In some cases, the motor of the hermetic electric compressor was burned. The present invention solves the above-mentioned problems of the prior art, and can protect the motor of the hermetic electric compressor without burning even when the refrigerant amount of the air conditioner is reduced or at a low voltage, and is compact. This is an overload protection device for a closed electric compressor. SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a thermal responsive device which is provided on the outer periphery of a hermetic electric compressor and operates according to the surface temperature of the compressor, a bimetallic contact, and a resistor. Temperature-sensitive overload protection device
It is a series circuit with the motor winding and is integrally molded. In addition, a temperature response type overload protection device of a direct heat type consisting of a thermal response device, a bimetal contact, and a resistance is formed in a series circuit, and is formed in a parallel circuit with an internal auxiliary winding circuit of a hermetic electric compressor. A thermoresponsive device is provided in parallel with the internal auxiliary winding circuit of the hermetic electric compressor and operates according to the winding temperature, and comprises a bimetallic contact and a resistor provided on the outer periphery of the hermetic electric compressor. The temperature-sensitive overload protection device of the direct heat type is a series circuit in which the load resistance and the electrodynamic terminal pin are provided in a parallel circuit with the bimetallic contact. According to the present invention, a heat responsive device is a direct-heated temperature-sensitive type overload protection device comprising a bimetal contact and a resistor, which is formed in a series circuit and integrally formed to provide a small input current. /> In case of overload of outgassing of the air conditioner, even if the current value is small, the thermal responsive device operates according to the outer temperature of the hermetic electric compressor to open the electric circuit to the hermetic electric compressor and stop the compressor. Thus, burning of the hermetic electric compressor is prevented. Further, the present invention provides a series circuit of a heat sensitive device and a temperature sensitive type overload protection device of a direct heating type comprising a bimetal contact and a resistor, which is formed in a parallel circuit with an internal auxiliary winding circuit of a hermetic electric compressor. Class with large input current
Even when the air conditioner is out of gas, the current flows through the hermetic electric compressor and the load resistance even when overloading occurs, the bimetal contact is reversed, the electric circuit to the hermetic electric compressor is opened, the compressor is stopped, and the hermetic type is closed. This is to prevent burnout of the electric compressor. Further, according to the present invention, by disposing the heat responsive device inside the hermetic electric compressor, the temperature of the motor winding can be sensed more accurately, and the protection of the hermetic electric compressor can be improved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An overload protection device for a hermetic electric compressor according to an embodiment of the present invention will be described below with reference to the drawings. The mounting method of the overload protection device is the same as that of the conventional example, and the description is omitted. FIG. 1 shows the first embodiment of the present invention .
Shows the embodiment, 1 is a motor of small hermetic electric compressor, consisting of a main winding 1a and the auxiliary winding 1b and the rotor (not shown). Numeral 2 is a direct heat type thermosensitive element which is formed integrally with a normally closed type bimetal contact 2a and a resistor 2b and a normally closed type thermoresponsive device 3 which operates according to the outer temperature of the hermetic electric compressor in a series circuit. This is a type overload protection device. [0015] When the current to the bimetal contacts 2a flows by
The metal itself generates heat, and when the current exceeds a set value and reaches a predetermined temperature, the bimetal contact 2a operates to open .
That, also the resistance 2b itself to <br/> heating is energized to simultaneously resistor 2b, the bimetal contact 2a is opened actuated also by the bimetal contacts 2a is heated by the heat. On the other hand, in parallel with the above operation, the thermal responsive device 3 detects the detected temperature.
Is higher than the set temperature, the circuit to the motor 1 is shut off. The operation of the above configuration will be described. When the AC power supply 4 is turned on in a small air conditioner such as a dehumidifier, current flows through the motor 1, the temperature-sensitive overload protection device 2, and the operation condenser 5, and the hermetic electric compressor 1 enters a steady operation state. The thermal response device 3 integrally formed with the temperature-sensitive overload protection device 2 and connected in series is a small-current air conditioner, so that the size thereof can be reduced. During operation of the hermetic electric compressor, for example, an overload state occurs, an overcurrent flows through the motor 1, and the bimetal contact 2a of the overload protection device 2 itself generates heat, and when a predetermined temperature is reached, the bimetal contact 2a is inverted. Then, the current to the motor 1 is cut off to stop the operation of the hermetic electric compressor. at the same time
The resistor 2b generates heat, and this heat also generates a bimetal contact.
2a is heated and when a predetermined temperature is reached, the bimetal contact 2
a reverses to shut off the current to the motor 1 and
Stop the operation of the compressor. When the refrigerant amount is smaller than the predetermined amount, the current flowing through the bimetal contact 2a is small, so that no heat is generated and the bimetal contact 2a does not reverse. However, the temperature of the main winding 1a and the auxiliary winding 1b of the motor 1 rises. At this time, the thermal responsive device 3 detects the outer temperature of the hermetic electric compressor of the small air conditioner, and opens the thermal responsive device 3 when the temperature exceeds the set temperature of the thermal responsive device 3, and opens the circuit to the motor 1. Shut off and stop the compressor to protect the hermetic electric compressor. FIG. 2 shows a bimetal contact 2a and a resistor 2b.
FIG. 2 is an external view of a direct-side heat type temperature-sensitive overload protection device 2 integrally formed in a series circuit with a heat responsive device 3 that operates according to the outer temperature of the hermetic electric compressor. FIG. 3 shows a second embodiment of the present invention .
In, 1 is the motor of a hermetic electric compressor of household air conditioner. It comprises a main winding 1a, an auxiliary winding 1b, and a rotor (not shown). Reference numeral 2 designates a normally closed bimetal contact 2a in series with the motor 1, a normally open thermal response device 3 which operates to close according to the outer temperature of the hermetic electric compressor, and a resistor 2b in parallel with the auxiliary winding 1b. This is a temperature-sensitive overload protection device of the direct heating type that is integrally formed as a circuit. The heated when current flows through the bimetal contacts 2a, the bimetal contact 2a own the current is greater than or equal to the specified
When the body generates heat and reaches a predetermined temperature, the bimetal contact 2a operates and opens. When the temperature is higher than the set temperature, the normally open thermal responsive device 3 closes and is energized by the resistor 2b to generate heat. The heat also heats the bimetal contact 2a to operate and open the bimetal contact 2a. This allows the motor 1
To shut off the circuit to. The operation of the second embodiment will be described. In the domestic air conditioner, when the AC power supply 4 is turned on, a current flows through the motor 1, the temperature-sensitive overload protection device 2, and the operation condenser 5, and the hermetic electric compressor 1 enters a steady operation state. During operation of the hermetic electric compressor, for example, an overload condition occurs, an overcurrent flows through the motor 1, and the bimetal contact 2a of the overload protection device 2 generates heat, and when the temperature exceeds a predetermined value and reaches a predetermined temperature, the bimetal contact 2a The contact 2a is reversed to interrupt the current to the motor 1 and stop the operation of the hermetic electric compressor. When the refrigerant amount is smaller than the predetermined amount, the current flowing through the bimetal contact 2a is small, so that no heat is generated and the bimetal contact 2a does not reverse. However, the temperature of the main winding 1a and the auxiliary winding 1b of the motor 1 rises. At this time , the normally open thermal responsive device 3 detects the outer temperature of the hermetic electric compressor, and when the temperature exceeds the set temperature of the thermal responsive device 3, the thermal responsive device 3 is closed and a small current flows through the resistor 2b. The bimetal contact 2a is heated by the heat, and the bimetal contact 2a operates to open. This shuts off the motor circuit and protects the hermetic electric compressor. In FIG. 4, the thermal responsive device 3 is installed inside the motor 1 to improve the protection effect implemented in FIG. As is apparent from the above description, the present invention does not increase the size of the temperature-sensitive type overload device, and provides both the normal overload protection and the condition in which the refrigerant amount is smaller than the predetermined amount . In this case, it is possible to protect the winding of the hermetic electric compressor from burning.

[Brief description of the drawings] FIG. 1 is a circuit diagram showing one embodiment of the present invention. FIG. 2 is a perspective view of the temperature-sensitive overload protection device of the present invention. FIG. 3 is a circuit diagram showing one embodiment of the present invention. FIG. 4 is a circuit diagram showing one embodiment of the present invention. FIG. 5 is a cross-sectional view of a conventional hermetic electric compressor. FIG. 6 is a circuit diagram showing a conventional example. [Explanation of symbols] 1 motor 2 Temperature-sensitive overload protection device 2a bimetal contact 2b resistance 3 Thermal response device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-144910 (JP, A) JP-A-6-131956 (JP, A) JP-A-5-202860 (JP, A) JP-A-2- 139820 (JP, A) JP-A-6-44884 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 1/00 371

Claims (1)

(1) A closed electric compressor provided with a single-phase motor having a main winding and an auxiliary winding, and a compressor surface provided outside the closed electric compressor. A heat sensitive device that operates according to temperature, and a temperature sensitive overload protection device of direct heat type consisting of bimetallic contacts and resistors that operate according to both current and temperature are connected in series and integrated. Protection of the hermetic electric compressor, which is formed so as to control the operation of the hermetic electric compressor by the heat responsive device and the bimetallic contact and the resistance during abnormal heat generation and large current flow of the hermetic electric compressor. apparatus.