JPS6112504Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a defrosting circuit for an air conditioner.

The defrost circuit of conventional air conditioners of this type is
As shown in the figure, a temperature regulator 2 is connected to the cooling/heating changeover switch 1, a defrost timer 4 is connected in parallel to a compressor relay coil 3 connected in series to the temperature regulator 2, and an electric line R101 The auxiliary relay coil 5, timer contact 7, and defrost thermostat 9 connected to the auxiliary relay coil 5 were connected in series, and the b contact 5b of the auxiliary relay 5 was connected to the four-way valve coil 8.

In the defrosting circuit configured as described above, when the contact 1a of the cooling/heating switch 1 is closed, the four-way valve coil 8 is turned on, the four-way valve is switched to the heating side, and the room temperature is adjusted to the setting of the temperature controller 2. If the value falls below this value, the contact 2a is closed, the compressor relay coil 3 is turned on, and heating operation is performed.

During the heating operation, the defrost timer 4 continues to run, and the timer contact 7 closes at regular intervals to issue a defrost command.

Further, during heating operation, if frost buildup exceeds a certain level, the contact point of the defrost thermostat 9, which issues a defrost command, closes. At this time, if the timer contact 7 is closed, the auxiliary relay coil 5 is turned on, the contact 5b is opened, the four-way valve coil 8 is turned off, and the refrigerant circuit is switched to the reverse cycle. Perform frost operation. During defrosting operation, defrosting is completed by a command from timer contact 7 or defrosting thermostat 9.

In a circuit configured in this way, if a defrost command is input to the defrost thermostat 9 after a defrost command by the timer has finished after a certain period of time, the defrost command will continue even though defrosting is necessary until the next defrost command by the timer. However, since the heating operation continues, not only does the heating capacity continue to decline for a long time, but the frost builds up solidly, making it difficult to defrost the next time.

In addition, since the defrost command by the timer ends after a certain period of time during operation, even if the frost has not been completely removed (in other words, the defrost thermostat 9
The defrosting operation ends even though it is still necessary (before the command to end the defrosting is issued), resulting in a decrease in heating capacity and a hardening of the frost, making it difficult to defrost the next time. The drawback was that frost became increasingly difficult.

Furthermore, during defrosting operation at low outside temperatures, the command to complete the defrosting operation is sent to the defrost thermostat 9 because the amount of frost formation is small.
However, due to the low outside temperature, as soon as heating operation starts, the temperature drops below the set temperature of the defrost thermostat 9 and a defrost command is issued.

There is a drawback that such a defrosting-heating operation is repeated many times within the defrosting operation time set by the defrosting timer.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional system. Defrosting is started by commands from the defrost timer and defrost thermostat, and defrosting is terminated by commands from the defrost thermostat only, even at low outside temperatures. A defrosting circuit for an air conditioner that is capable of preventing repeated heating for defrosting during defrosting operation, and preventing damage caused by a time lag between a defrost timer command and a defrost command issued by a defrost thermostat. The purpose is to provide

Embodiments of the defrosting circuit for an air conditioner according to this invention will be described below with reference to the drawings. FIG. 2 is a circuit diagram of one embodiment. In this Figure 2,
The same parts as in FIG. 1 will be described with the same reference numerals.

In FIG. 2, reference numeral 1 denotes a cooling/heating changeover switch, which has a heating side contact 1a and a cooling side contact 1b, and a movable contact is connected to a power source (not shown).
The cooling side contact 1a is connected to the electric line R105. The cooling side contact 1b is the fixed contact 2 of the temperature regulator 2.
connected to b. A fixed contact 2a of this temperature regulator 2 is connected to an electric line 101. The fixed contact 2a is connected to the heating side contact 1a of the cooling/heating changeover switch 1 and is closed when the temperature decreases, and the movable contact of the temperature regulator 2 is connected to the connection point _P1 .
This fixed contact 2a is used to control on/off of the compressor. The connection point _P1 is connected to the electric circuit S102 via the compressor relay coil 3, and is also connected to the b contact 6b of the second auxiliary relay 6.
It is connected to the fixed contact 5a of the switching contact of the first auxiliary relay 5 via. The movable contact of this switching contact is connected to the electric line S102 via the defrost timer motor 4.

Further, the connection point P ₁ is connected to the movable contact of the switching contact 7 of the defrost timer motor 4, and this switching contact 7 has fixed contacts 7a and 7b, and the fixed contact 7a is connected to the defrost thermostat 9 and the switching contact 7. 1 is connected to the electric circuit S102 via the auxiliary relay 5.

Further, the fixed contact 7b of the switching contact 7 is connected to the electric line S102 via the second auxiliary relay 6.
This fixed contact 7b is connected to the contact 5b of the first auxiliary relay. The fixed contact 7a of the switching contact 7 is connected to the electric circuit R101 via the contact 5c (normally open) of the first auxiliary relay 5.

Furthermore, a series circuit of the four-way valve coil 8 and the contact 5d (normally closed) of the first auxiliary relay 5 is connected between the electric line R101 and the electric line S102.

Next, the operation of the defrosting circuit of the air conditioner of this invention constructed as above will be explained. If the heating side contact 1a of the cooling/heating changeover switch 1 is closed,
The four-way valve coil 8 is turned on, the refrigerant circuit becomes a heating circuit, and when the room temperature is lower than the set value of the temperature controller 2, the fixed contact 2a is closed, the compressor relay coil 3 is turned on, and heating operation starts.

At this time, the switching contact 7 of the defrost timer motor 4
If the fixed contact 7b is closed, the defrost timer motor 4 continues to rotate, and the fixed contact 7a is closed after a certain period of time. At this time, if the defrosting thermostat 9 is closed, the first auxiliary relay 5 is turned on, its contact 5d is opened, the four-way valve coil 8 is turned off, and defrosting operation begins.

Here, the operation of the defrost thermostat 9 will be explained. This detects the temperature of the pipes and fins of the outdoor heat exchanger, and for example, turns on at -12℃, turns on at +
Turns off at 2°C.

Next, when the defrosting operation starts, the first auxiliary relay 5
When the fixed contact 5a is closed, the contact 5c is also closed. Also, the b contact 6b of the second auxiliary relay 6
is closed, and the defrost timer motor 4 continues to rotate for a certain period of time, for example, after 40 seconds, when the fixed contact 7b of the switching contact 7 is closed, the b contact 6b of the second auxiliary relay 6 is opened, and the defrost timer motor 4 stops. do. Then, the defrosting operation ends when the defrosting thermostat 9 is opened.

It has been confirmed through experiments that the defrost thermostat 9 does not open earlier than the fixed contact 7a of the switching contact 7 opens when the defrost setting time of the defrost timer 4 is set to 1 minute or less.

Furthermore, contact point 5c, defrost thermostat 9,
Since a series circuit of the first auxiliary relay 5 is formed, even when the fixed contact 2a of the temperature regulator 2 is opened during defrosting, the defrosting thermostat 9
The defrosting operation can be continued until the door is opened.

As described above, according to the defrosting circuit of the air conditioner of this invention, the cooling/heating changeover switch is set as the heating side contact, the refrigerant circuit becomes the heating circuit, the defrosting timer motor is rotated for a predetermined period of time, and then the defrosting thermostat is turned on. When turned on, the first auxiliary relay is energized to enter defrost operation, and after the defrost timer motor has been rotated for a predetermined period of time, the second auxiliary relay cuts off the energization circuit of the defrost timer motor, resulting in the following effects: It is something that plays.

(1) Damage caused by the time lag between the defrost command by the defrost timer motor and the defrost command by the defrost thermostat is also eliminated, and damage caused by the defrost termination being terminated by the defrost timer motor is also eliminated. .

(2) Defrost timer This prevents the motor from repeating defrosting and heating within the set time.

(3) For example, if the set time of the defrost timer motor has passed during defrosting operation, contact 7b of the defrost timer motor closes and the defrost thermostat is waiting to open, and the temperature controller is manually turned on. Even if the contact on the heating side were to be opened, the problem of defrosting ending prematurely is also eliminated.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional air conditioner defrosting circuit, and FIG. 2 is a circuit diagram showing an embodiment of the air conditioner defrosting circuit of this invention. 1...Cooling/heating changeover switch, 1a...Heating side contact, 1b...Cooling side contact, 2...Temperature controller, 3
... Relay coil for compressor, 4 ... Defrost timer motor, 5 ... First auxiliary relay coil, 6 ... Second auxiliary relay coil, 7 ... Defrost timer motor switching contact, 8 ... Four-way valve coil, 9...Defrost thermostat, 101, 102...Single-phase electrical circuit, and the same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of claim for utility model registration] (1) Heating side contact 1 connected to the first electrical circuit during heating
a, and switches to the cooling side contact 1b during cooling, and a four-way valve that is excited when switched to the heating side contact 1a and switches the refrigerant circuit of the air conditioner to the heating circuit. The valve coil 8 and the first
It has a heating side contact 2a connected to the electric line 101 and a cooling side contact 2b connected to the cooling side contact 1b, and when the room temperature is lower than the set value during heating, a movable contact is connected to the heating side contact 1a. and when the room temperature rises above a set value, the movable contact switches to the cooling side contact 2b.
and a compressor relay coil 3 that is excited to drive the compressor when the movable contact of the temperature regulator 2 is connected to the heating side contact 2a during heating, and a second auxiliary relay. The defrost timer motor 4 connected to the normally closed contact 6b of 6, the second contact 5a of the first auxiliary relay 5, and the second electrical circuit 102 is connected between the movable contact of the temperature regulator 2 and the second electrical circuit 102. The movable contact of the switching contact 7 of the defrost timer motor 4 is connected to the movable contact of the temperature regulator 2, and a 2 auxiliary relay 6 is connected to the defrost timer motor 4 via the second contact 5b of the first auxiliary relay 5, and the first switching contact 7
The contact 7a of the defrost timer motor 9 and the first auxiliary relay 5 of the defrost timer motor 9 are connected in series to the second electric circuit 102, and the third normally open contact 5 of the first auxiliary relay 5 is connected in series.
c is connected between the first electric circuit 101 and the first contact 7a of the switching contact 7, and the four-way valve coil 8 and the first
The fourth normally closed contact 5d of the auxiliary relay 5 is connected to the first
A defrosting circuit for an air conditioner, characterized in that it is connected between an electric line 101 and a second electric line 102. (2) The defrosting circuit for an air conditioner according to claim 1, wherein the defrosting time setting value of the defrosting timer motor 4 is 2 minutes or less.