JP3446109B2 - Starter for refrigerator motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting device for a compressor motor for an electric refrigerator.

[0002]

2. Description of the Related Art A conventional starting device for a compressor motor for an electric refrigerator will be described with reference to FIG . The single-phase induction motor 10 including the main winding 12 and the starting winding 13 arranged at a position that causes a phase difference with respect to the main winding 12 has a positive characteristic thermistor (hereinafter, referred to as PTC for starting) 15 The starting device consisting of is connected in series with the starting winding 13 and is connected to the power supply E via the overload relay 14. When the power supply voltage is applied to the single-phase induction motor 10 at the time of start-up, the start-up PTC 15 is at room temperature at the time of start-up, so the resistance is low and a large current flows to the start-up winding 13 side to rotate the rotor (not shown). Let Then, the single-phase induction motor 10
When the start-up starts, the start-up PTC 15
The current passing through C self-heats and becomes a high resistance, and the current flowing through the starting winding becomes a small value, resulting in normal operation.

However, in the above configuration, the starting P
Since a large current of several amps to ten and several amps has to be applied to the TC for 0.5 seconds to several seconds at the time of startup, a considerable heat capacity is required. For this reason, in order to suppress the current in the starting winding even after shifting to the steady operation, it is necessary to keep the starting PTC in a high temperature and high resistance state, and continue to consume power of 2W to 4W to save power. It was an obstacle.

Further, in the structure using the starting PTC, there is a problem that the starting is difficult even if the motor is restarted immediately after it is stopped. That is, since the PTC for start-up has a large heat capacity, if the temperature and resistance become high during operation, it will take several tens of seconds to several minutes for the temperature to drop to near room temperature and become ready for restarting after stopping the motor, Even if it is attempted to restart before that, only a small current flows in the starting winding because the starting PTC has a high resistance, the motor is in a rotor restrained state, and a large current flows in the main winding 12. The load relay 14 was activated and could not be restarted. Since the recovery time of the overload relay 14 is initially shorter than the cooling period until the PTC for startup can be restarted, the overload relay 14 is repeatedly operated and reset several times, and the temperature becomes high sequentially. Time will increase. Then, the recovery time of the overload relay 14 becomes longer than the cooling time of the starting PTC described above, so that the electric motor can be started. Such a situation
In the case of compressor motors for refrigerators, this occurs when the door is opened and the temperature inside the refrigerator rises and the thermostat is turned on immediately after the refrigerator internal temperature drops and the thermostat turns off and the compressor motor stops. It was In such a case, not only time is required for restarting, but also the life of the overload relay 14 is shortened as described above.

Therefore, as Japanese Patent Application No. 5-200955 and Japanese Patent Application No. 5-112234, as shown in FIG. 8 , a starting PTC 15 connected in series to the starting winding 13, the starting winding 13 and the starting winding 13 are provided. Bidirectional controlled rectifying device (hereinafter referred to as TRIAC) connected in series with the PTC 15 for power supply.
16 and the PTC 15 for activation are connected in parallel,
A starter has been proposed which has one terminal connected to the gate of the triac 16 and an auxiliary positive temperature coefficient thermistor 17 (hereinafter referred to as an auxiliary PTC) having a heat capacity smaller than that of the starting PTC.

According to this type of starting device, when the power supply voltage is applied to the single-phase induction motor 10 at the time of starting,
A trigger signal is applied to the gate of the triac 16 connected in series with the starting winding 13 through the auxiliary PTC 17, the triac 16 is energized, and a current for starting the single-phase induction motor 10 flows through the starting winding 13. When the single-phase induction motor 10 is started, the temperature of the auxiliary PTC 17 becomes high, and the current applied to the gate of the triac 16 becomes small,
The triac turns off. After that, in the steady state of the single-phase induction motor 10, the current continues to flow in the auxiliary PTC 17, but since the auxiliary PTC 17 has a smaller heat capacity than the starting PTC 15, the power consumption for keeping the auxiliary PTC 17 at high temperature and high resistance is extremely high. It can be small. Further, even when the single-phase induction motor 10 is restarted immediately after it is once stopped, since the heat capacity of the auxiliary PTC 17 is small, it can be restarted by immediately cooling and turning on the triac 16.

[0007]

However, in this method, the triac and the auxiliary PT, which are semiconductors that are weak against heat, are used.
A time circuit composed of C is housed in the same container as the PTC for start-up, which becomes hot due to self-heating due to the start-up winding current at the time of start-up, and further, the temperature of the compressor motor becomes relatively high during the cooling operation of the refrigerator. Since it is used by being inserted into an airtight terminal attached to a metal hermetically sealed container stored therein, the ambient temperature of the triac may rise from 80 to 90 ° C depending on the conditions. Maximum allowable temperature of semiconductor junction inside TRIAC is generally 1
It is 25 ° C, and the allowable temperature rise is 1 at the junction due to the on loss of the triac due to the starting winding current at startup.
Since the temperature must be within the difference between 25 ℃ and ambient temperature, the difference becomes small when the ambient temperature is high, and it is necessary to select an expensive triac with a small temperature rise at the junction even if the same current is applied, that is, a large current capacity. was there. Even in such a case, the temperature of the joint may exceed 125 ° C. in the event of an abnormal condition such as a restricted operation of the compressor motor, which may reduce the reliability. Further, the excellent restarting characteristics provided by the auxiliary PTC having a small heat capacity and a short cooling time may be impaired due to the high ambient temperature. The present invention has been made to solve the above problems, and an object thereof is to improve the reliability of a starter device for an electric refrigerator compressor motor that consumes less power and can be restarted in a short time, and at a low cost. To provide.

[0008]

In order to solve the above problems, a starting device for a compressor motor for a refrigerator according to the present invention includes a starting PTC part, a triac, an auxiliary PTC and a resistor, which reduces power consumption and improves restart characteristics. The time circuit is separated, the former PTC part for starting is inserted into the airtight terminal attached to the metal closed container of the compressor, and the latter time circuit part is separated from the metal closed container. It is characterized in that it is installed at a location, for example, a control component storage part of a refrigerator.

[0009]

According to the starting device of the present invention, the maximum ambient temperature of the triac or the auxiliary PTC may be 40 to 50 ° C., so that the allowable temperature of the triac junction is 125
There is a difference of 75 to 85K from the ambient temperature of 80 to 90 ° C and the allowable temperature of 125 ° C is 35 to 4K.
It is about twice the value of 5K. Therefore, even if an inexpensive triac having a small current capacity is used, the temperature of the triac junction due to the starting winding current can be kept at 125 ° C. or lower. Further, even if the compressor motor is in a restrained state and becomes high in temperature, the heat does not destroy the triac.
Furthermore, the auxiliary PTC is cooled quickly, and good restart characteristics can be secured. Further, by mounting the timed circuit portion on the printed wiring board, it is not necessary to store the timed circuit portion in a small case, and the convection of air around the triac is improved, so that the heat dissipation plate for the triac can be miniaturized. Further, recent refrigerators are often controlled by electronic circuits. In that case, by incorporating the timed circuit portion integrally with the control electronic substrate portion, a dedicated substrate becomes unnecessary. Furthermore, when using a microcomputer or IC, it is possible to use part of these functions to simplify the timed circuit part, and to minimize the cost for reducing the power consumption of the startup device. You can stay Further, the PTC starting relay, which is widely used for starting the compressor motor for a refrigerator, can be used as it is.
Although the present invention has been described with respect to the refrigerator motor as described above, it is obvious that the present invention is not limited to this and can be applied to a general single-phase induction motor.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those of the above-mentioned conventional example are designated by the same reference numerals, and the description thereof will be omitted. FIG. 1 shows a starting device for a refrigerator compressor motor according to a first embodiment of the present invention.
Is a circuit diagram, and (b) is a partial cross-sectional view showing a mounted state.
The compressor motor 10 is housed in the closed container 1 and connected to the airtight terminal 2. Reference numeral 5 is a PTC start relay having a built-in start PTC, which is inserted and attached to the airtight terminal 2 and has terminals S, P and R on the outside. After the start-up of the compressor motor 10 is completed, the time circuit portion 4 for cutting off the power supply to the start-up PTC.
(Hereinafter referred to as a timed circuit portion) is a triac 1
6. The auxiliary PTC 17 and the resistor 18 and the terminals S, P and M, which are attached to, for example, a refrigerator controller storage part, which is away from the closed container 1 so as not to be affected by the heat of the compressor, start the PTC. The connection with the relay 5 is made by a lead wire having connection terminals at both ends. Reference numeral 19 is a CR absorber, which suppresses the voltage increase rate dV / dt at the time of turning off the triac to protect the triac.

Next, FIG. 2 shows an example of the structure of the above-mentioned time-limited circuit portion 4. (a) is a plan view, (b) is a front view, (c) is a side view, and the auxiliary PTC 17 is housed. The auxiliary PTC unit 7 and the triac 16 are fixed by attaching and soldering the triac unit 6 in which the metal plate 6A that also serves as the heat dissipation plate and the terminal P is screwed, the resistor 18, the terminal S, the terminal M, and their components. It is composed of a printed wiring board 4A for electrical connection.

FIG. 3 shows an example of an internal structure in which the cover of the auxiliary PTC unit 7 is removed, and the auxiliary PTC 17 has a concave portion at the center and has a constant contact pressure between two arcuate springs 7A, 7A which are arranged to face each other. And the arcuate springs 7A and 7A are respectively supported by terminal fittings 7B and 7B arranged outside thereof. The terminal fittings 7B, 7B project below the auxiliary PTC case 7C and are soldered to the copper foil portion of the printed wiring board.

4 and 5 show the starting device of the present invention for each starting method of the compressor motor . As shown in FIG.
Shows the phase-split start-up method, Fig. 4 (b) shows the phase-split start-up capacitor run method, and Fig. 5 (c) shows the capacitor-start-up capacitor run method. 5 (d) and (e) are perspective views showing the PTC start relay used for each starting method. The three-terminal type PTC start relay of (d) is for the phase split starting method and the four-terminal type of (e). Is applied to the phase-split start capacitor run method and the capacitor start capacitor run method. Reference numeral 8 is a starting capacitor, and 9 is an operating capacitor.

FIG . 6 shows another embodiment to which the present invention is applied when the electric refrigerator is controlled by an electronic circuit. (A) is an example when the electric refrigerator uses a microcomputer. By controlling the gate circuit of the triac from the output port of the microcomputer via a resistor and a phototriac coupler, the triac is turned on at startup. ， It can be turned off when the startup is completed. (B) is an example of a circuit in which the triac is turned on for a fixed time by a monostable multivibrator using an IC. (C) is an example of a circuit that turns on the triac for a certain time after the power is turned on by the Schmitt circuit of the transistor.

[Brief description of drawings]

FIG. 1 shows a starting device for a compressor motor for an electric refrigerator according to a first embodiment of the present invention, in which (a) is a circuit diagram,
(B) is a partial sectional view showing a mounted state.

2A and 2B show an example of the timed circuit portion of the above, where (A) is a plan view, (B) is a front view, and (C) is a side view.

FIG. 3 is a diagram showing an internal structure of the above auxiliary PTC unit without a cover.

FIG. 4 shows various starting methods of the single-phase induction motor according to the present invention, where (a) is a phase-dividing start method and (b) is a phase-dividing start capacitor run method.

FIG. 5 shows a starting method of a single-phase induction motor according to the present invention and
The PTC start relay is shown, and (c) is the capacitor start.
Capacitor run method, (d) and (e) each have 3 terminals
Type and 4 terminal type PTC start relay.

FIG. 6 is a circuit diagram showing another embodiment to which the present invention is applied when the electric refrigerator is controlled by an electronic circuit.

FIG. 7 is a circuit diagram of a conventional single-phase induction motor starting device.

FIG. 8 is a circuit diagram of another conventional single-phase induction motor starting device.

[Explanation of symbols]

1 Compressor metal closed container 2 Airtight terminal 4 Timed circuit that shuts off power to the PTC for startup 4A printed wiring board 5 PTC start relay 6 TRIAC unit 6A Metal plate for heat sink and terminal P 7 Auxiliary PTC unit 7A, 7A bow spring 7B, 7B terminal fittings 7C auxiliary PTC case 8 Starting capacitor 9 operating capacitors 10 Compressor motor (single-phase induction motor) 12 main winding 13 Starting winding 14 Overload relay 15 PTC for startup 16 triacs 17 Auxiliary PTC 18 Resistance 19 CR absorber

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02K 17/30 H02P 1/42

Claims (3)

(57) [Claims] 1. A power supply to a starting positive temperature coefficient thermistor connected in series with the starting winding of a refrigerator compressor motor using a single-phase induction motor having a main winding and a starting winding is cut off after completion of starting. In a starter device of a method of saving power consumption, the starting positive temperature coefficient thermistor is attached to the surface of a metal closed container of a compressor, and electricity is supplied to the starting positive temperature coefficient thermistor at a position separated from the metal closed container. It is characterized by the provision of a time circuit for shutting off,
Motor starter for refrigerator. 2. A bidirectional control rectifying element connected in series to the starting positive temperature coefficient thermistor, and a parallel circuit to the starting positive temperature coefficient thermistor. The bidirectional controlled rectifying element, which is connected to the gate of the bidirectional controlled rectifying element and has an auxiliary positive characteristic thermistor having a heat capacity smaller than that of the starting positive temperature coefficient thermistor. Of the gate current bypass resistor connected between the gate and the gate-side electrode, and for connecting those circuit components to the heat sink for the bidirectional control rectifier and the startup positive temperature coefficient thermistor. The starting device for a motor for a refrigerator according to claim 1, wherein the terminal metal fitting and the container containing the auxiliary positive temperature coefficient thermistor are attached to a printed wiring board. 3. A time circuit for interrupting the power supply to the startup positive temperature coefficient thermistor is integrally formed with a control electronic board portion as a part of a control electronic circuit of a refrigerator. No. 1 refrigerator motor starter.