JPH11136980A - Cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cooler in which power consumption of the starting auxiliary winding circuit of a motor for driving refrigeration cycle is reduced and the motor is restarted smoothly after instantaneous power interruption. SOLUTION: A positive characteristic thermistor (PEC) 7, a PTC relay 8 being switched through a control circuit 21, an overload relay 5 and a compressor relay 4 are connected in series between a power supply 6 and the auxiliary winding 3 of a single phase induction motor 1. The control circuit 21 opens the PTC relay 8 upon elapsing a specified time after turn on power in order to save power of the circuit of auxiliary winding 3. Furthermore, means for detecting pressure of refrigerant in an evaporator 13 in the refrigeration cycle, temperature of chill being delivered into a refrigerator, temperature of a delivery pipe of the single phase induction motor, power supply current, oscillation of the single phase induction motor 1, terminal voltage of the overload relay 5, or the like, are provided. Based on the output from these detection means, a state equivalent to the operating state the overload relay 5 is detected and the PTC relay 8 is kept in closed state through the control circuit 21 thus restarting the motor smoothly after instantaneous power interruption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device using a single-phase induction motor used in refrigerators and refrigerators.

[0002]

2. Description of the Related Art In a cooling device such as a refrigerator-freezer, a positive-characteristic thermistor (hereinafter, referred to as "thermistor") is provided in order to cut off a current to an auxiliary winding of a single-phase induction motor immediately after the single-phase induction motor is shifted from a starting stage to a steady operation. PTC). In such an apparatus, in order to achieve energy saving in the PTC, Japanese Utility Model Publication No. 61-111985,
A technique as disclosed in Japanese Patent No. 339291 is known.

FIG. 7 shows a configuration disclosed in Japanese Utility Model Publication No. 61-111985, and (1) shows a single-phase induction motor (compressor) for driving a refrigeration cycle of a refrigerator. This single-phase induction motor (1) is provided with a main winding (2) for generating a steady torque required for continuation of a steady operation, and an auxiliary winding (3) for generating a startup torque required only at startup. ing.

[0004] One of the main windings (2) is a single-phase induction motor (1).
Is connected to a power supply (6) via a power relay (4) (hereinafter referred to as a "compressor relay") for turning on / off the operation of the other, and the other is connected to a relay coil (32) and an overload relay (5). Connected to the power supply (6). Auxiliary winding
One of (3) is connected to a power source (6) via a relay (4) like the main winding (2), and the other is a normally open relay contact.
The circuit (33) and the PTC (7) are connected in series, and the power supply (6) is connected via an overload relay (5).

When the compressor relay (4) is turned on and energized,
A current flows through the main winding (2) to generate a steady torque. Further, the relay coil (32) closes the relay contact (33), a current also flows through the auxiliary winding (3) to generate a starting torque, and the single-phase induction motor (1) starts.

However, since the main winding (2) has a high load, the relay contacts (33) are fully started while chattering until the start is completed, and the operation is eventually switched to a steady operation. In this state, the current of the relay coil (32) decreases, the relay contact (33) opens, no current flows through the PTC (7), and the temperature of the PTC (7) becomes normal temperature.

FIG. 8 shows a configuration disclosed in Japanese Patent Application Laid-Open No. 6-339291. (1) is a single-phase induction motor for driving a refrigeration cycle. This single-phase induction motor (1) has
Main winding that generates the steady torque required for continuous steady operation
(2) and an auxiliary winding (3) for generating a necessary starting torque only at the time of starting.

One of the main windings (2) is a single-phase induction motor (1)
Is connected to a power supply (6) via a compressor relay (4) for turning on / off the operation of the other, and the other is connected to a power supply (6) via an overload relay (5).

One of the auxiliary windings (3) is connected to a power supply (6) via a compressor relay (4) like the main winding (2), and the other is connected to a PTC (7) and a triac (3). 30) are connected in series and connected to a power source (6) via an overload relay (5). An auxiliary PTC (31) is connected between the gate of the triac (30) and one terminal of the auxiliary winding (3), that is, a terminal on the power supply side.

When the compressor relay (4) is turned on and energized, a current flows through the main winding (2) and a steady torque is generated. Also,
Since the auxiliary PTC (31) has a low resistance at room temperature, a gate current flows through the triac (30), the triac (30) is closed, and the PTC (7) also has a low resistance at room temperature. ), A current flows to generate a starting torque, and the motor starts.

Thereafter, when the temperature of the auxiliary PTC (31) rises and its resistance value increases, almost no current flows, the gate current of the triac (30) decreases, the triac (30) opens, and the auxiliary winding (30) opens. (3) No current flows at all, and the operation switches to steady operation. Then, no current flows through the PTC (7) at all, and the temperature of the PTC (7) becomes normal temperature.

[0012]

In the configuration shown in FIG. 7 described above, chattering occurs at the relay contact (33) at the time of startup, noise is generated even in a normal power supply state, and the life of the relay contact is shortened. There is a problem. Further, when power supply conditions and ambient temperature conditions are unstable, chattering may occur even during steady operation.

In the configuration shown in FIG. 8, considering the wide ambient temperature in practical use, for example, a triac at 35 ° C.
If the resistance value is low enough to operate (30), the current increases at 10 ° C. and the gate of the triac (30) is broken. The auxiliary PTC (31) having a low resistance temperature characteristic corresponding to such a wide ambient temperature has a problem that the resistance does not increase even during the steady operation and the power consumption is large.

As a means for solving the above problem, there is a technique using a power relay. This will be described with reference to FIG. In the configuration shown in FIG. 9, the auxiliary PTC (31) and the triac (30) in FIG. 8 are removed, and a power relay (hereinafter, referred to as a PTC relay) (8) is connected in series with the PTC (7).

Therefore, in FIG. 9, the compressor relay (4) and P
When TC relay (8) is turned on at the same time, single phase induction motor
A power supply voltage is applied to (1), a current flows through the main winding (2), and a steady torque is generated. At the same time, the PTC (7) has a low resistance since it is at room temperature, and has a low resistance. A current also flows through (3) to generate a starting torque, and the single-phase induction motor (1) starts.

The PTC (7) has a high temperature and a high resistance due to self-heating a while after the current flows, and the auxiliary winding (3)
Only a small amount of current flows, and the starting torque disappears,
The operation is switched to the steady operation by the steady torque generated in the main winding (2). The control circuit (21) turns off the PTC relay (8) after a certain period of time has passed since it was turned on.

By using the PTC relay (8) as described above, at the time of steady operation, no current flows through the PTC (7) at all, and no power is consumed. Also, during steady operation, since no current flows through the PTC (7), the PTC (7) is naturally cooled by ambient room temperature air, and the single-phase induction motor
When (1) is turned off, the PTC (7) has already returned to normal temperature and low resistance, and when it is turned on again at that time, the single-phase induction motor (1) starts.

However, the configuration shown in FIG. 9 has the following problem. For example, if the time from stop to restart of the single-phase induction motor (1) is extremely short, such as when an instantaneous power failure occurs during steady-state operation of the single-phase induction motor (1), Even if current flows to the auxiliary winding side and a starting torque is generated, the load becomes high due to the pressure balance of the refrigeration cycle, the single-phase induction motor (1) cannot start, and the overload relay (5) operates. There is.

Under such conditions, the overload relay
When (5) operates, the compressor relay (4) remains ON, and the PTC relay (8) operates as an overload relay.
Regardless of the presence or absence of the operation of (5), it turns off after a certain period of time has passed since it was turned on. Therefore, even if the overload relay (5) returns and turns on again, the compressor relay (4)
Is ON and the PTC relay (8) remains OFF, so that the starting torque cannot be obtained, the overload relay (5) operates again, and the power is cut off. ) Had a problem that it could not be started.

[0020]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a single unit for driving a refrigeration cycle having a main winding and an auxiliary winding and including an evaporator, a condenser and the like. A phase induction motor, a positive temperature coefficient thermistor (hereinafter referred to as a PTC) connected in series with the auxiliary winding, and a current flowing through the auxiliary winding when the single-phase induction motor is started and connected in series with the PTC. A cooling system comprising: a PTC relay for interrupting a current to the auxiliary winding during a steady rotation of the single-phase induction motor; and an overload relay connected in series to the single-phase induction motor. Pressure detection means is provided in the evaporator forming the refrigeration cycle as drive detection means for detecting the drive state of the PTC relay, and the opening and closing of the PTC relay is controlled based on the detection output of the pressure detection means. It is characterized in.

According to a second aspect of the present invention, there is provided a single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; And a current flowing through the auxiliary winding connected to the PTC in series with the PTC and starting the single-phase induction motor, and interrupting the current flowing through the auxiliary winding during a steady-state rotation of the single-phase induction motor. In a cooling device provided with a PTC relay to perform the operation and an overload relay connected in series to the single-phase induction motor, current detection is performed in series with the overload relay as drive detection means for detecting a drive state of the refrigeration cycle. Means for controlling opening and closing of the PTC relay based on a detection output of the current detection means.

According to a third aspect of the present invention, there is provided a single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; And a current flowing through the auxiliary winding connected to the PTC in series with the PTC and starting the single-phase induction motor, and interrupting the current flowing through the auxiliary winding during a steady-state rotation of the single-phase induction motor. A PTC relay and an overload relay connected in series to the single-phase induction motor, wherein the discharge into the freezing chamber of the refrigerating cycle is performed as drive detecting means for detecting a driving state of the refrigerating cycle. Temperature detecting means is provided to sense the air temperature, and the temperature is detected based on the temperature detected by the temperature detecting means.
The opening and closing of the TC relay is controlled.

According to a fourth aspect of the present invention, there is provided a single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; And a current flowing through the auxiliary winding connected to the PTC in series with the PTC and starting the single-phase induction motor, and interrupting the current flowing through the auxiliary winding during a steady-state rotation of the single-phase induction motor. In a cooling device provided with a PTC relay and an overload relay connected in series to the single-phase induction motor, the drive detection means for detecting the driving state of the refrigeration cycle is provided on the surface of the single-phase induction motor. Providing vibration detection means for detecting vibration of the phase induction motor,
The opening and closing of the PTC relay is controlled based on the detection output of the vibration detecting means.

According to a fifth aspect of the present invention, there is provided a single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; And a current flowing through the auxiliary winding connected to the PTC in series with the PTC and starting the single-phase induction motor, and interrupting the current flowing through the auxiliary winding during a steady-state rotation of the single-phase induction motor. In a cooling device provided with a PTC relay to be operated and an overload relay connected in series to the single-phase induction motor, a voltage between terminals of the overload relay is detected as detection means for detecting a driving state of the refrigeration cycle. Voltage detection means for controlling the opening and closing of the PTC relay based on the voltage detected by the voltage detection means.

According to a sixth aspect of the present invention, there is provided a single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; And a current flowing through the auxiliary winding connected to the PTC in series with the PTC and starting the single-phase induction motor, and interrupting the current flowing through the auxiliary winding during a steady-state rotation of the single-phase induction motor. In a cooling device provided with a PTC relay and an overload relay connected in series to the single-phase induction motor, a detection pipe for detecting a driving state of the refrigeration cycle is connected to a discharge pipe from the single-phase induction motor. A temperature detecting means is provided, and the opening and closing of the PTC relay is controlled based on the temperature detected by the temperature detecting means.

(Function) In the first aspect of the present invention, FIG.
As shown in (1), when the compressor relay (4) and the PTC relay (8) are simultaneously turned on, the power supply voltage is applied from the power supply (6) to the single-phase induction motor (1), and the current flows through the main winding (2). As a result, a steady torque is generated, and at the same time, the resistance value of the PTC (7) is low at room temperature. Therefore, a current also flows through the auxiliary winding (3) to generate a starting torque, and the single-phase induction motor (1) is driven. to start. After a short time after the current flows through the PTC (7), self-heating causes high temperature and high resistance, the current flowing through the auxiliary winding (3) decreases, the starting torque disappears, and the current is generated in the main winding (2). The operation is switched to the steady operation with the steady torque.

The control circuit (21) includes a compressor relay (4) and a PT
After a certain period of time has elapsed since the C relay (8) was turned on, the PTC relay (8) is turned off. PTC relay as above
By using (8), during steady operation, no current flows through the PTC (7) at all, and no power is consumed.

Also, during steady operation, since no current flows through the PTC (7), the PTC (7) is naturally cooled by ambient normal temperature air, and is already turned off when the single-phase induction motor (1) is OFF.
Has returned to normal temperature and low resistance. Therefore, the single-phase induction motor (1) can be started even if it is turned off and then immediately turned on.

However, during the steady-state operation of the single-phase induction motor (1), the operation from the stop to the restart of the single-phase induction motor (1), for example, when a momentary power failure occurs or when the outlet is plugged in or out. Is performed in an extremely short time, no matter how much the current flows to the auxiliary winding side and the starting torque is generated, the load is high due to the pressure balance in the refrigeration cycle driven by the single-phase induction motor (1). And a single-phase induction motor (1)
May not be activated and the overload relay (5) may operate.

The compressor relay (4) and the PTC relay (8)
Are turned on at the same time, the PTC relay (8) is usually turned off after a certain period of time by the control circuit (21), but the refrigerant pressure in the evaporator (13) is measured by the pressure sensor (15), If the refrigerant pressure does not change despite the ON operation of the single-phase induction motor (1), it is determined in the same manner as when the overload relay (5) operates, and the PTC relay
(8) is maintained in the ON state by the control circuit (21). Thus, when the overload relay (25) returns, the compressor relay (4) and the PTC relay (8) are both in the ON state, and the single-phase induction motor (1) can be restarted.

According to a second aspect of the present invention, as in the first aspect, during a steady operation of the single-phase induction motor (1), when an instantaneous power failure occurs or when an outlet is plugged in and out, etc. If the operation from the stop to the restart of the single-phase induction motor (1) is performed in an extremely short time, no matter how much the current flows to the auxiliary winding side and the startup torque is generated, the pressure balance in the refrigeration cycle can be reduced. In relation to this, the single-phase induction motor (1) becomes heavily loaded, cannot start, and the overload relay (25) may operate.

After the compressor relay (4) and the PTC relay (8) are turned on at the same time, the PTC relay (8) usually operates as a control circuit.
It is turned off after a certain time from ON by (21),
When the current flowing to the single-phase induction motor (1) is detected by the current sensor (16) connected in series to the overload relay (5) and it is detected that the current stops flowing, the overload relay (5) operates. Judge in the same way as
The relay (8) is kept on by the control circuit (21). Thus, when the overload relay (5) returns, both the compressor relay (4) and the PTC relay (8) are in the ON state, and the single-phase induction motor (1) can be restarted.

According to a third aspect of the present invention, as in the first aspect, during a steady operation of the single-phase induction motor (1), when an instantaneous power failure occurs or when an outlet is plugged in or out, etc. If the operation from the stop to the restart of the single-phase induction motor (1) is performed in an extremely short time, no matter how much the current flows to the auxiliary winding side and the startup torque is generated, the pressure balance in the refrigeration cycle can be reduced. In relation to this, the single-phase induction motor (1) becomes heavily loaded, cannot start, and the overload relay (5) may operate.

After the compressor relay (4) and the PTC relay (8) are turned on at the same time, the PTC relay (8) usually operates on the control board.
It is turned off after a certain time from ON by (21),
The temperature of the discharged air from the cooling fan (14) into the freezer compartment is detected by a temperature sensor (17), and if the discharged air temperature does not decrease at that time, an overload relay (5)
The PTC relay (8) is maintained in the ON state by the control circuit (21) in the same manner as in the case of operating. Thus, when the overload relay (5) returns, both the compressor relay (4) and the PTC relay (8) are in the ON state, and the single-phase induction motor (1) can be restarted.

According to a fourth aspect of the present invention, in the same manner as in the first aspect, during a steady operation of the single-phase induction motor (1), when an instantaneous power failure occurs, or when an outlet is plugged in or out, etc. If the operation from the stop to the restart of the single-phase induction motor (1) is performed in an extremely short time, no matter how normally the current flows to the auxiliary winding side and the startup torque occurs, the relationship between the pressure balance of the refrigeration cycle and the As a result, the single-phase induction motor (1) becomes high in load, cannot start, and the overload relay (5) may operate.

After the compressor relay (4) and the PTC relay (8) are turned on at the same time, the PTC relay (8) usually operates on the control board.
It is turned off after a certain time from ON by (21),
Vibration sensor mounted on the surface of single-phase induction motor (1)
(18) The vibration of the single-phase induction motor (1) is detected. At this time, when the stationary of the single-phase induction motor (1) is detected, the PTC is determined in the same manner as when the overload relay (5) is operated.
The relay (8) is maintained in the ON state by the control circuit (21). As a result, when the overload relay (5) returns, both the compressor relay (4) and the PTC relay (8) are turned off.
In the N state, the single-phase induction motor (1) can be restarted.

According to a fifth aspect of the present invention, as in the first aspect, during a steady operation of the single-phase induction motor (1), when an instantaneous power failure occurs, or when an outlet is plugged in or out, etc. If the operation from the stop to the restart of the single-phase induction motor (1) is performed in an extremely short time, no matter how normally the current flows to the auxiliary winding side and the startup torque occurs, the relationship between the pressure balance of the refrigeration cycle and the Therefore, the single-phase induction motor (1) may be overloaded, and the single-phase induction motor (1) may not be able to start, and the overload relay (5) may operate.

After the compressor relay (4) and the PTC relay (8) are turned on at the same time, the PTC relay (8) usually operates on the control board.
It is turned off after a certain time from ON by (21),
A voltage between both terminals of the overload relay (5) is detected by a voltage sensor (19) installed between both terminals of the overload relay (5). When the operation of the overload relay (5) is confirmed by the detection output of the voltage sensor (19), the PTC relay (8) is maintained in the ON state by the control circuit (21). Thus, when the overload relay (5) returns, both the compressor relay (4) and the PTC relay (8) are in the ON state, and the single-phase induction motor (1) can be restarted.

According to the sixth aspect of the present invention, as in the case of the first aspect, during a steady operation of the single-phase induction motor (1), when an instantaneous power failure occurs or when an outlet is connected and disconnected, etc. If the operation from the stop to the restart of the single-phase induction motor (1) is performed in an extremely short time, no matter how normally the current flows to the auxiliary winding side and the startup torque occurs, the relationship between the pressure balance of the refrigeration cycle and the Therefore, the single-phase induction motor (1) becomes high in load, cannot start, and the overload relay (5) may operate.

After the compressor relay (4) and the PTC relay (8) are turned on at the same time, the PTC relay (8) usually operates as a control circuit.
It is turned off after a certain time from ON by (21),
When the temperature of the discharge pipe is detected by the temperature sensor (20) attached to the discharge pipe from the single-phase induction motor, the temperature of the discharge pipe increases due to the detected temperature even though the compressor relay (4) is in the ON state. If not, it is determined in the same manner as the operation of the overload relay (5), and the PTC relay (8) is maintained in the ON state by the control circuit (21). Thus, when the overload relay (5) returns, both the compressor relay (4) and the PTC relay (8) are in the ON state, and the single-phase induction motor (1) can be restarted.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a configuration diagram of Embodiment 1 of the present invention. In FIG. 1, (1) is a single-phase induction motor. The single-phase induction motor (1) has a main winding (2) for generating a steady torque necessary for continuation of a steady operation, and a single-phase induction motor (1). An auxiliary winding (3) for generating an appropriate starting torque is provided.

One of the main windings (2) is connected to one end of a power supply (6) via a compressor relay (4) for turning on / off the single-phase induction motor (1), and the other is an overload relay.
It is connected to the other end of the power supply (6) via (5).

One of the auxiliary windings (3) is connected to one end of the power supply (6) through a compressor relay (4) like the main winding (2), and the other is a low resistance at room temperature. The PTC (7) having high resistance at high temperature and the overload relay (5) are connected in series to the power supply (6).

The single-phase induction motor (1) is provided with a condenser (1).
0), a dryer (11), a capillary tube (12), and an evaporator (13) to form a refrigeration cycle.
(13) has a pressure sensor (15). Compressor relay
When (4) and the PTC relay (8) are simultaneously turned on, a power supply voltage is applied to the single-phase induction motor (1), a current flows through the main winding (2), and a steady torque is generated. ) Has low resistance at room temperature, so that a current also flows through the auxiliary winding (3) to generate a starting torque, and the single-phase induction motor (1) starts.

After a short time after the current flows through the PTC (7), self-heating causes high temperature and high resistance, and the auxiliary winding (3)
Only a small amount of current flows, and the starting torque disappears,
The operation is switched to the steady operation by the steady torque generated in the main winding (2). The control circuit (21) is composed of a compressor relay (4) and a PT.
After a certain time from when the C relay (8) is turned on, the PTC relay
(8) is turned off. By using the PTC relay (8) as described above, at the time of steady operation, no current flows through the PTC (7) at all, and power consumption in the auxiliary winding (3) is eliminated. It is also effective in terms of the life of the overload relay (5).

Further, since no current flows through the PTC (7) during the steady operation, the PTC (7) is naturally cooled by the ambient normal temperature air, and when the single-phase induction motor (1) is turned off, the PTC (7) is already turned off.
(7) returns to normal temperature and low resistance, and the single-phase induction motor (1) can be started normally even if it is turned on immediately.

However, during the steady-state operation of the single-phase induction motor (1), the operation from stop to restart of the single-phase induction motor (1), for example, when a momentary power failure occurs or when an outlet is plugged in or out. Is performed in an extremely short time, no matter how normally the current flows on the auxiliary winding side and the starting torque occurs, the single-phase induction motor (1)
Becomes high load, the single-phase induction motor (1) cannot start, and the overload relay (5) may operate.

After the compressor relay (4) and the PTC relay (8) are turned on at the same time, the PTC relay (8) usually operates as a control circuit.
It is turned off after a certain time from ON by (21),
The refrigerant pressure in the evaporator (13) is measured by the pressure sensor (15). If the refrigerant pressure does not change even though the compressor relay (4) is ON, the overload relay (5) is activated. Judgment equivalent to the case of operation, PTC relay
(8) is maintained in the ON state by the control circuit (21). As a result, when the overload relay (5) returns, both the compressor relay (4) and the PTC relay (8) are turned on.
In this state, the single-phase induction motor (1) can be restarted.

(Embodiment 2) FIG. 2 is a block diagram of Embodiment 2 of the present invention, in which parts corresponding to those of Embodiment 1 shown in FIG. The startup operation of the cooling device of the second embodiment shown in FIG. 2 is substantially the same as that of the first embodiment.

In FIG. 2, an overload relay
(5) A current sensor (16) is provided in series with the current sensor.
The current flowing to the single-phase induction motor (1) is detected by (16), and when it is detected that the current no longer flows, it is determined that the overload relay (5) is operated, and the control circuit (21) determines Maintain the PTC relay (8) in the ON state.

(Embodiment 3) FIG. 3 is a block diagram of Embodiment 3 of the present invention, and the same reference numerals are given to portions corresponding to Embodiment 1 shown in FIG. 1, and description thereof will be omitted. The startup operation of the cooling device of the third embodiment shown in FIG. 3 is substantially the same as that of the first embodiment.

In the third embodiment shown in FIG. 3, a temperature sensor (17) is provided so as to sense the temperature of the air discharged into the freezer compartment by the cooling fan (14).
The temperature of the air discharged from the cooling fan (14) is detected by (17). At this time, if the temperature of the discharged air does not decrease even though the compressor relay (4) is ON, it is determined that the overload relay (5) operates, and the control circuit (21). ) By PTC relay
(8) is maintained in the ON state. Subsequent operations are the same as those in the first embodiment.

(Embodiment 4) FIG. 4 is a block diagram of Embodiment 4 of the present invention. In FIG. 4, parts corresponding to those of Embodiment 1 shown in FIG. The start-up operation of the cooling device of the fourth embodiment shown in FIG. 4 is substantially the same as that of the first embodiment.

In Embodiment 4 shown in FIG. 4, a vibration sensor (18) is provided on the surface of the single-phase induction motor (1), and the vibration of the single-phase induction motor (1) is detected by the vibration sensor (18). At this time, if the stationary state of the single-phase induction motor (1) is detected even though the compressor relay (4) is ON, it is determined that the operation is the same as when the overload relay (5) is operated. By (21), the PTC relay (8) is maintained in the ON state.

(Embodiment 5) FIG. 5 is a block diagram of Embodiment 5 of the present invention, in which parts corresponding to those of Embodiment 1 shown in FIG. The starting operation of the cooling device of the fifth embodiment shown in FIG. 5 is almost the same as that of the first embodiment.

In Embodiment 5 shown in FIG. 5, a voltage sensor (19) is provided between both terminals of the overload relay (5), and the overload relay (5) is operated by the voltage sensor (19).
(5) The voltage between both terminals is detected. And the voltage sensor
When it is confirmed from the voltage between the terminals of the overload relay (5) detected in (19) that the state is the same as the case where the overload relay (5) operates, the control circuit (21) controls the PTC relay (8). Maintain the ON state. Subsequent operations are the same as in the first embodiment.

(Embodiment 6) FIG. 6 is a block diagram of Embodiment 6 of the present invention, in which parts corresponding to Embodiment 1 shown in FIG. The startup operation of the cooling device of the sixth embodiment shown in FIG. 6 is substantially the same as that of the first embodiment.

In Embodiment 6 shown in FIG. 6, a temperature sensor (20) is provided in the discharge pipe of the condenser of the refrigeration cycle, and the temperature sensor (20) detects the temperature of the discharge pipe or its vicinity. If the temperature of the discharge pipe or its vicinity does not rise even though the compressor relay (4) is ON, it is determined that the operation of the overload relay (5) is the same as when the overload relay (5) has been operated. ) By PTC
The relay (8) is kept on. Subsequent operations are the same as in the first embodiment.

[0059]

As described above, according to the present invention, by turning off the PTC relay, no current flows through the PTC at the time of steady operation, and the power consumption of the PTC at the time of steady operation can be eliminated. Also, since no current flows through the PTC during steady operation, the PTC is naturally cooled by ambient room temperature air, and when the motor is turned off, the PTC at that time is turned off.
C has returned to normal temperature and low resistance, and even if it is turned on immediately thereafter, the motor can be started smoothly.

After the compressor relay and the PTC relay are turned on at the same time, the PTC relay is normally turned off a fixed time after being turned on by the control circuit. Detected current detected by a current sensor provided in series with the load relay, detected temperature of cool air discharged from the cooling fan detected by the temperature sensor, vibration of the electric motor detected by the vibration sensor, and both terminals of the overload relay detected by the voltage sensor When it is detected that the operation of the overload relay is equivalent to the operation of the overload relay from the detected voltage of the discharge port of the single-phase induction motor detected by the voltage and the temperature sensor between the PTCs,
The relay is kept on by the control circuit. Thus, when the overload relay returns, both the compressor relay and the PTC relay are in the ON state, so that the electric motor can be restarted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram according to a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram of a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional example.

FIG. 8 is a configuration diagram of a conventional example.

FIG. 9 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single phase induction motor (compressor) 2 Main winding 3 Auxiliary winding 4 Compressor relay 5 Overload relay 6 Power supply 7 PTC 8 PTC relay 10 Condenser 11 Dryer 12 Capillary tube 13 Evaporator 14 Cooling fan 15 Pressure sensor 16 Current sensor 17 Temperature sensor 18 Vibration sensor 19 Voltage sensor 20 Temperature sensor 21 Control circuit 30 Triac 31 Auxiliary PTC 32 Relay coil 33 Relay contact

Claims (6)

[Claims] 1. A single-phase induction motor (compressor) having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator and a condenser, and connected in series with the auxiliary winding. A positive-characteristic thermistor (hereinafter referred to as PTC), which is connected in series with the PTC to supply a current to the auxiliary winding when the single-phase induction motor is started, and to set the auxiliary winding when the single-phase induction motor is in a steady rotation. In a cooling device provided with a PTC relay for interrupting a current to the refrigeration cycle and an overload relay connected in series to the single-phase induction motor, the refrigeration cycle is used as drive detection means for detecting a drive state of the refrigeration cycle. A cooling device, wherein a pressure detecting means is provided in the evaporator forming the PTC relay, and the opening and closing of the PTC relay is controlled based on a detection output of the pressure detecting means. 2. A single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; a PTC connected in series with the auxiliary winding; The P
A PTC connected in series with the TC to supply a current to the auxiliary winding when the single-phase induction motor is started, and to cut off a current to the auxiliary winding when the single-phase induction motor is rotating at a steady state;
In a cooling device provided with a relay and an overload relay connected in series to the single-phase induction motor, a current detection unit is provided in series with the overload relay as drive detection unit for detecting a drive state of the refrigeration cycle. A cooling device for controlling the opening and closing of the PTC relay based on a detection output of the current detection means. 3. A single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; a PTC connected in series with the auxiliary winding; The P
A PTC connected in series with the TC to supply a current to the auxiliary winding when the single-phase induction motor is started, and to cut off a current to the auxiliary winding when the single-phase induction motor is rotating at a steady state;
In a cooling device provided with a relay and an overload relay connected in series to the single-phase induction motor, as a drive detecting means for detecting a drive state of the refrigeration cycle, a temperature of air discharged into the freezer chamber in the refrigeration cycle as a drive detection means. A temperature detecting means for detecting the temperature of the PTC relay, and controlling the opening and closing of the PTC relay based on the temperature detected by the temperature detecting means. 4. A single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; a PTC connected in series with the auxiliary winding; The P
A PTC connected in series with the TC to supply a current to the auxiliary winding when the single-phase induction motor is started, and to cut off a current to the auxiliary winding when the single-phase induction motor is rotating at a steady state;
In a cooling device provided with a relay and an overload relay connected in series to the single-phase induction motor, the single-phase induction motor is provided on the surface of the single-phase induction motor as drive detection means for detecting a drive state of the refrigeration cycle. A cooling device, comprising: vibration detection means for detecting vibration of an electric motor; and controlling opening and closing of the PTC relay based on a detection output of the vibration detection means. 5. A single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; a PTC connected in series with the auxiliary winding; The P
A PTC connected in series with the TC to supply a current to the auxiliary winding when the single-phase induction motor is started, and to cut off a current to the auxiliary winding when the single-phase induction motor is rotating at a steady state;
In a cooling device provided with a relay and an overload relay connected in series to the single-phase induction motor, a voltage for detecting a voltage between terminals of the overload relay as detection means for detecting a driving state of the refrigeration cycle. A cooling device comprising a detecting means, wherein opening and closing of the PTC relay is controlled based on the voltage detected by the voltage detecting means. 6. A single-phase induction motor having a main winding and an auxiliary winding for driving a refrigeration cycle including an evaporator, a condenser, and the like; a PTC connected in series with the auxiliary winding; The P
A PTC connected in series with the TC to supply a current to the auxiliary winding when the single-phase induction motor is started, and to cut off a current to the auxiliary winding when the single-phase induction motor is rotating at a steady state;
In a cooling device provided with a relay and an overload relay connected in series to the single-phase induction motor, temperature detection is performed on a discharge pipe from the single-phase induction motor as detection means for detecting a driving state of the refrigeration cycle. Means for detecting the temperature of the PTC based on the temperature detected by the temperature detecting means.
A cooling device characterized by controlling opening and closing of a relay.