JPH09285066A - Protector of electric compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach a thermal protective relay to an existing starting relay and an overload relay, by housing the thermal protective relay within an insulating case, and attaching it to the terminal of the starting relay, at the mounting section provided at this insulating case. SOLUTION: For a protector, a thermal protective relay 18 is attached to the terminal 25 of a starting relay 5, using an insulating case 26 made of synthetic resin. For the insulating case 26, a housing to house the thermal protective relay 18 and a mounting section are made integrally. The thermal protective relay 18 housed in the insulating case 26 is attached to the starting relay 5 by plugging-in a holding terminal to the terminal 25 of the starting relay 5. Between terminals 8 and 9 of the starting relay 5, a PTC element 7 is connected to its one end, and also, an operation capacitor 15 is connected to the other end projected outside. A terminal 23 at one end of the thermal protective relay 18 is connected to a terminal 16 of the overload relay 1, and a terminal 24 at the other end to an AC electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat protection device for an electric compressor used in a refrigerator or the like.

[0002]

2. Description of the Related Art Conventionally, electric compressors have been used in actual developments such as 59-
As disclosed in Japanese Patent No. 34466, a starting relay composed of a resistance element having a positive temperature coefficient of resistance (PTC) and an overload relay for interrupting the electric power supply to the electric motor when the electric motor is overloaded are mounted. FIG. 13 shows a mounting structure for such a starting relay and an overload relay, and FIG. 9 shows a circuit diagram showing the electrical connection between them, which will be described below.

Reference numeral 1 is a cylindrical overload relay, in which a bimetal switch 2 and a heater 3 are connected in series and housed. To the terminal 17 of the overload relay 1, one end of the pin re-stable 4 is fixed by welding. Reference numeral 5 is a starting relay, and a PTC element 7 is housed in a case 6 made of synthetic resin. The starter relay 5 is fitted and attached to airtight terminals C, R, and S, which are provided by penetrating the back surface side (not shown) into the outer wall of the hermetic container of the compressor. In the case 6, terminals 8 and 9 to which the PTC element 7 is connected are provided so as to project perpendicularly to the paper surface. Terminals 8 and 9 are compressor single-phase induction motors 10 via airtight terminals S and R of the compressor, respectively.
Is connected to the main winding M and the auxiliary winding A of the.

The overload relay 5 is a holder 11 made of synthetic resin.
It is held by the annular portion 12 and is connected to the starting relay 5 by the connecting portion 13. The free end 14 of the pin restable 4 is locked to the connecting portion 13 of the holder 11 and connected to the common connection point (airtight terminal C) of the main winding M and the auxiliary winding A of the electric motor 10. The operating capacitor 15 is connected between the terminals 8 and 9 of the starting relay 5, and the single-phase AC power supply is connected to the terminal 9 of the starting relay 5.
And a terminal 16 of the overload relay 1 are connected.

With the above construction, when the electric motor 10 is started, the temperature of the PTC element 7 of the starting relay 5 is low and has a low resistivity. Therefore, a large starting current flows through the auxiliary winding A and the electric motor 10 is started. . After that, the PTC element 7 self-heats due to the current flowing therethrough and has a high resistivity to reduce the current flowing through the auxiliary winding A. Then, during operation, the electric motor 10 is operated by the phase difference between the auxiliary winding current and the main winding current due to the operating capacitor 15. Electric motor 1 during operation
When 0 is overloaded, an overcurrent flows through the heater 3 of the overload relay 1 to raise the temperature, and the bimetal switch 2 is opened to stop the supply of power to the electric motor 10. Thus, the electric motor 10 is prevented from being damaged when the electric motor 10 is overloaded.

[0006]

By the way, in addition to preventing damage due to overcurrent at the time of overload by the overload relay 1 as described above, abnormal heat generation of the compressor due to stop of the cooling fan of the compressor or the like. Fig. 1 to prevent damage due to
As shown in 0, it is possible to connect the thermal protection relay 18 that opens and closes the contact according to the ambient temperature to the overload relay 1 in series,
It is known in Japanese Utility Model Publication No. 62-198463. The thermal protection relay 18 has a bimetal 19 as shown in FIG.
An arm 21 for opening and closing the contact 20 with a bimetal 19 is housed in a rectangular parallelepiped case 22 made of synthetic resin shown in FIG. 12 ((a) is a plan view and (b) is a front view), and two terminals 23 are provided. , 24 are included.

The heat protection relay 18 is arranged in the vicinity of the hermetically sealed container of the compressor, and is attached to, for example, the outer wall of the starting relay 5 or the overload relay 1. In this case, start relay 5
It is necessary to provide a mounting member for mounting the thermal protection relay 18 on the outer wall of the or overload relay 1, and the existing starting relay 5 or overload relay 1 that does not use the thermal protection relay 18
Can not be used.

Therefore, an object of the present invention is to provide a compressor protection device which has a versatile versatility in which the thermal protection relay 18 can be easily attached to the existing starting relay and overload relay. .

[0009]

SUMMARY OF THE INVENTION The present invention is a starting relay having a plurality of protruding terminals which are fitted into and mounted on airtight terminals provided through a side wall of a hermetically sealed container of an electric compressor. In a protective device for an electric compressor, which includes a heat protection relay that is provided close to a closed container and opens contacts when a predetermined temperature is reached, the heat protection relay is housed in an insulating case and Mount to the terminal or terminal hole of the starting relay using the mounting part provided on the case. The thermal protection relay can be attached to an existing starting relay using the terminals or terminal holes of the starting relay.

Further, the protective device for an electric compressor according to the present invention includes an overload relay connected between the electric motor of the electric compressor and a power source, and a P connected in series with an auxiliary winding of the electric motor.
It comprises a TC element, a thermal protection relay connected in series with the PTC element, and an operating capacitor connected in parallel with a series circuit of the PTC element and the thermal protection relay. When the thermal protection relay operates to open its contact and the power supply to the electric motor is stopped and then the power is supplied to restart, the PTC element is released from the auxiliary winding of the electric motor. The motor does not start, overcurrent flows in the circuit and the overload relay operates, disconnecting the motor from the power supply.

Further, according to the protective device for an electric compressor of the present invention, the terminal of the starting relay is held by the mounting portion of the insulating case of the thermal protection relay and is electrically connected to one terminal of the thermal protection relay. A terminal can be provided to simultaneously attach the thermal protection relay and make an electrical connection to the starting relay.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing a protective device for an electric compressor according to the present invention. The same parts as those in FIG. 13 described in the prior art are designated by the same reference numerals. The electrical connection of this protection device is the same as the circuit diagram shown in FIG.

In the protective device of the present invention, the thermal protection relay 18 is attached to the terminal 25 of the starting relay 5 using an insulating case 26 made of synthetic resin. The insulating case 26 is shown in FIG.
((A) is a plan view, (b) is a front view, (c) is a side view)
As shown in FIG.
And the mounting portion 28 are integrally formed. The rectangular parallelepiped heat protection relay 18 shown in FIG. 12 is press-fitted from the side opening 29 of the housing portion 27 of the insulating case 26, and the terminals 23 and 24 are projected from the side opening 29 and housed. The upper surface of the insulating case 26 is open, and the mounting portion 2 is provided on the side opening 29 side.
8 are formed. A grip terminal 30 for gripping the terminal 25 of the starting relay 5 is press-fitted into the mounting portion 28.

The heat protection relay 18 housed in the insulating case 26 is attached to the starting relay 5 by inserting the gripping terminal 30 into the terminal 25 of the starting relay 5. The starter relay 5 is provided with a protrusion by inserting one end of the terminals 8, 9 and 25 into a terminal hole provided in the case 6 as needed.

FIG. 3 is a side view showing a state in which the heat protection relay 18 is attached to the starting relay 5, and the heat protection relay 18
A predetermined space S is provided between the start relay 5 and the start relay 5 so that the heat protection relay 18 does not operate due to the heat of the start relay 5.

In FIG. 1, between the terminals 8 and 9 of the starting relay 5, a PTC element 7 is connected to one end of the starting relay 5 and an operating capacitor 15 is connected to the other end thereof protruding outward. Nothing is electrically connected to the terminal 25 and it is an empty terminal. One terminal 23 of the thermal protection relay 18 is connected to the terminal 16 of the overload relay 1 by wiring, and the other terminal 24 is connected to an AC power source by wiring. Then, the terminal 9 of the starting relay 5 is connected to the AC power source by wiring, and the AC power source is supplied to the electric motor 10 of the compressor.

4 and 5 ((a) is a plan view, (b) is shown in FIG.
Is a front view, and (c) is a side view) showing other forms of the insulating case 26. As with the one shown in FIG. 2, the housing 27 for housing the thermal protection relay 18 and the terminals of the starting relay 5 are shown. And a mounting portion 28 for mounting to 25. In these insulating cases 26, the structure of the mounting portion 28 is different from that of FIG.

That is, in the structure shown in FIG.
Has a mounting hole 31 through which the terminal 25 of the starting relay 5 is inserted. The heat protection relay 1 is attached to the starting relay 5 by inserting the terminal 25 of the starting relay 5 into the mounting hole 31.

The insulating case 26 shown in FIG. 5 is provided with a mounting piece 32 at the mounting portion 28 which extends in the same direction as the insertion direction of the thermal protection relay 18. The thermal protection relay 1 is attached to the starting relay 5 by inserting the attachment piece 32 into the terminal hole of the starting relay 5 of the insulating case 26.

The insulating case 26 shown in FIG. 4 and FIG.
Since it can be configured by integrally forming a synthetic resin, it can be inexpensive.

By the way, in the circuit configuration shown in FIG.
Since the thermal protection relay 18 is connected to the common line of the main winding M and the auxiliary winding A of the electric motor, a large current flows through the thermal protection relay 18. Therefore, the contact 20 of the thermal protection relay 18 must be large so as to withstand a large current. Therefore, the circuit configuration of FIG. 6 in which the contact 20 of the heat protection relay 18 is small will be described below.

In the circuit configuration shown in FIG. 6, the thermal protection relay 1
Are connected in series to the PTC element 7. FIG. 7 shows a front view of a protection device having such a circuit configuration. 6 and 7, the same parts as those in FIGS. 13 and 9 are designated by the same reference numerals. The PTC element 7 of the starting relay 5 has a terminal 8,
25, and the operating capacitor 15 is connected between terminals 8 and 9. As shown in FIG. 8, the heat protection relay 1 is housed in an insulating case 26 similar to that shown in FIG. 2, and one of the terminals 23 is a grip terminal 30 provided on a mounting portion 28.
Is electrically connected by a connecting piece 32. The thermal protection relay 18 housed in the insulating case 26 in this manner is attached by inserting the gripping terminal 30 into the terminal 25 of the starting relay 5, and at the same time, the terminal 25 of the starting relay 5 and the terminal of the thermal protection relay 18. 23 is electrically connected. Therefore, the wiring connection between the terminal 23 of the heat protection relay 18 and the terminal 25 of the starting relay 5 becomes unnecessary. Then, an AC power supply is connected to the terminal 16 of the overload relay 1 and the terminal 24 of the thermal protection relay 18 by wiring.

In the circuit configuration of FIG. 6, when the fan for cooling the compressor fails and the temperature of the hermetically sealed container of the compressor rises, and the thermal protection relay 18 operates (contact 20 is released), the auxiliary winding A Although the PTC element 7 is cut off, the electric motor 10 of the compressor is not stopped because the AC power source is still connected to the electric motor 10.
However, when the power supply to the electric motor 10 is cut off by the thermocycle and the compressor is stopped while the thermal protection relay 18 is operating, when the electric power is supplied to the electric motor 10 again, the PTC element 7 is removed from the circuit. Since it is cut off, the electric motor 10 does not start, an overcurrent flows through the electric motor 10, the overload relay 1 operates, and the bimetal switch 2 is released.

Thus, by configuring the circuit as shown in FIG. 6, even if the temperature of the compressor rises abnormally, the compressor can be protected, and the thermal protection relay 18 is connected to the auxiliary winding A. Therefore, in the circuit configuration of FIG. 10, the current flowing in the common line is much smaller than the current flowing in the common line, so that the thermal protection relay 18 having the small contact 20 can be used.

[0026]

As described above, according to the present invention, since the mounting portion of the insulating case accommodating the heat protection relay is attached to the terminal or the terminal hole of the starting relay, the existing starting relay is used. Also, the heat protection relay can be easily attached, which is versatile and can suppress the cost increase.

By connecting the thermal protection relay in series to the PTC, the wiring connection between the thermal protection relay and the starting relay can be eliminated, and the contact of the thermal protection relay can be small, so that the cost can be reduced. It can be further reduced.

[Brief description of drawings]

FIG. 1 is a front view of a protective device for an electric compressor according to the present invention.

FIG. 2 is a diagram showing a state in which a heat protection relay is housed in an insulating case of the present invention, (a) is a plan view, (b) is a front view, and (c) is a side view.

FIG. 3 is a side view showing a state in which a heat protection relay is attached to the starting relay of the present invention.

FIG. 4 is a diagram showing an insulating case of the present invention, in which (a) is a plan view, (b) is a front view, and (c) is a side view.

FIG. 5 is a diagram showing an insulating case of the present invention, (a) is a plan view, (b) is a front view, and (c) is a side view.

FIG. 6 is a circuit diagram of a protective device for an electric compressor according to the present invention.

FIG. 7 is a front view of a protective device for an electric compressor according to the present invention.

FIG. 8 is a view showing a state in which a heat protection relay is housed in the insulating case of the present invention.

FIG. 9 is a circuit diagram of a conventional protection device for an electric compressor.

FIG. 10 is a circuit diagram of a conventional protection device for an electric compressor.

FIG. 11 is a circuit diagram of a thermal protection relay.

FIG. 12 is a diagram showing an appearance of a heat protection relay, (a)
Is a plan view and (b) is a front view.

FIG. 13 is a front view of a conventional protective device for an electric compressor.

[Explanation of symbols]

 1 Overload Relay 5 Starting Relay 7 PTC Element 8 Terminal 9 Terminal 10 Motor 15 Operating Capacitor 18 Thermal Protection Relay 23 Terminal 24 Terminal 26 Insulation Case 28 Mounting Part 30 Gripping Terminal

Claims (4)

[Claims] 1. A starting relay having a plurality of protruding terminals, which is fitted into an airtight terminal penetrating a side wall of a hermetically sealed container of an electric compressor, and which is provided close to the hermetically sealed container. In a protective device for an electric compressor, which is provided with a heat protection relay that opens a contact when a predetermined temperature is reached, the heat protection relay is housed in an insulating case, and the mounting provided in the insulating case. A protective device for an electric compressor, characterized in that the protective device is attached to a terminal of the starting relay in a section. 2. A starting relay having a plurality of terminals that are fitted and fitted to an airtight terminal that penetrates a side wall of a hermetically sealed container of an electric compressor and that is close to the hermetically sealed container. In a protective device for an electric compressor, which is provided with a heat protection relay that opens a contact when a predetermined temperature is reached, the heat protection relay is housed in an insulating case, and the mounting provided in the insulating case. A protective device for an electric compressor, which is attached to a terminal hole of the starting relay at a section. 3. An overload relay connected between the electric motor of the electric compressor and a power source, a PTC element connected in series with an auxiliary winding of the electric motor, and a PTC element connected in series with the PTC element, A protective device for an electric compressor, comprising a thermal protection relay that opens a contact when a predetermined temperature is reached, and an operating capacitor that is connected in parallel to a series circuit of the PTC element and the thermal protection relay. 4. A grip terminal for gripping a terminal of the starting relay and being electrically connected to one terminal of the thermal protection relay is provided on a mounting portion of the insulating case. The protective device for the electric compressor described.