JPS6024910B2 - Refrigeration equipment control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control circuit for controlling the internal temperature of a refrigeration device such as a refrigerator, a freezer, or a refrigerator/freezer showcase.

In conventional refrigerators, when the temperature detected by the temperature detection unit installed at one location inside the refrigerator becomes higher than the set value,
The fan motor for the cold air pestle and the compressor motor for compressing the cold soot were both rotated. In such a secondary refrigerator, if there is a large amount of food or other items to be frozen in the refrigerator, or if the refrigerator is placed unevenly, the temperature distribution inside the refrigerator will be uneven, and this can cause the temperature to change by chance. Even if only the temperature near the detection part rises and the temperature in other parts of the camp is lower than the set value, both the fan motor and the compressor motor rotate. Therefore, even if the temperature inside the refrigerator is equalized, even if the temperature is lower than the set value, the combustor motor can be turned on only by the partial temperature near the detection part.
Since the off-control is performed, the compressor motor is operated more than necessary, and most of the electric power consumed by the refrigerator is consumed by the compressor motor, resulting in extremely wasteful electric power consumption. The purpose of the present invention is to improve the above-mentioned drawbacks.Even if the temperature of the detection part in the sensor rises above the set value, the fan motor is first rotated for a certain period of time without immediately rotating the combustor motor. The temperature inside the refrigerator is made uniform, and the compressor motor is also rotated only when the detected temperature continues to be higher than the set value.

Therefore, unnecessary operation of the compressor motor can be avoided. Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, a power switch 2 is placed at both ends of a commercial power supply 1.
A series circuit of a cold air fan motor 3 and its relay contact 4, and a series circuit of a refrigerant compression compressor motor 5 and its relay contact 6 are connected in parallel to each other via.

In addition, a full-wave rectifier 8, a stabilizing circuit 9, and smoothing capacitors 10 and 11 are connected to the commercial power supply 1 via a transformer 7 in order to obtain a predetermined DC power supply, and a DC power supply is also provided as an output terminal. A power supply terminal 12 is provided.

-Next, 13 is a control circuit that controls the fan motor 3 and compressor motor 5 based on a temperature detection signal, and is configured as follows.

14 is a temperature detection circuit, and this circuit 14 connects in series a negative characteristic thermistor 15 and a resistor 16 as a temperature sensing element to detect the temperature inside the refrigerator, and a fixed resistor 17 and a resistor 16 to set the temperature inside the refrigerator. A variable resistor 18 is connected in series, and a connection point A between the thermistor 15 and the resistor 16 is connected to the positive side of the comparator 19.
The movable point B of the variable resistor 18 is configured by connecting it to the negative side.

The output side of the comparator 19 is directly connected to the drive relay circuit 201 of the fan motor 3 and is also connected to the drive relay circuit 22 of the compressor motor 5 via a delay timer circuit 21. .

The delay timer circuit 21 includes a set signal forming section 23
, a reset signal forming section 24, a time setting section 25, and an AND circuit 26.
The AND output of the output 03 of the comparator 19 is sent to the compressor motor relay circuit 22. The drive relay circuits 20 and 22 of the fan motor 3 and the combustor motor 5 each include a resistor 27,
28, 29, 30, transistors 31, 32, relay coils 33, 34, and diodes 35, 36.

Next, the operation of the present invention will be explained based on the drawings.

First, when the movable point B of the variable resistor 18 is operated to set the desired internal temperature and the power switch 2 is turned on, the answer "Power on?" becomes YES in the flowchart of FIG.

Here, if it is assumed that the temperature inside the refrigerator becomes higher than the set value at time T, then "Is the temperature inside the refrigerator > the set value?" becomes YES.

When the combustor motor 5 is running, "Is the combustor in progress?"
is YES and returns to the initial state, or initially the fan motor 3 in the refrigerator is turned on since the answer to ``Is Comb On?'' is NO. That is, at time T, when the temperature inside the refrigerator becomes higher than the set value, the resistance value of the thermistor 15 having negative characteristics decreases, so that the input voltage on the positive side of the comparator 19 becomes higher than the input voltage on the negative side. Then, comparator 1
The output 03 of 9 becomes H level as shown in FIG.
is turned on as shown in FIG. 3, and the fan motor 3 is driven.
At the same time, the output 03 of the comparator 19 is transmitted to the timer circuit 21.
Since the timer time setting section 25 is connected to the set signal forming section 23 as shown in FIG.
Then, by the trigger signal of this timer set, the other output ○ is set to the daily level as shown in FIG. 2 and 5. When this state continues and reaches T2 (the time set by the time setting section 25 of the timer circuit 21 is L-T), "Is the timer up?" in FIG. 3 becomes YES, and the combinator motor 5 is turned on. That is, at time T2, the output ○ of the timer circuit 21 changes to the L level as shown in FIG. 2, and the output C2 changes to the H level as shown in FIG. 6.
Since this world power P2 is input to the AND circuit 26 at H level together with the output 03 of the comparator 19, the output of this AND circuit 26 is at H level and the relay circuit 22 for driving the compressor motor 5 is inputted. The transistor 33 is turned on, the relay coil 34 is energized, the combustor motor relay contact 6 is turned on as shown in FIG. 2, and the refrigeration cycle is started. At time T3, when the inside of the refrigerator is cooled by the drive of the compressor motor 5 and the temperature inside the refrigerator becomes lower than the set value, the resistance value of the thermistor 15 increases, so the input voltage on the positive side of the comparator 19 becomes negative. lower than the side input voltage.

In other words, "Is the temperature inside the refrigerator > the set value?" is NO, and the comparator 1
The output 03 of the motor 9 changes to the L level as shown in FIG. 2, and the fan motor relay contact 4 also changes to OFF as shown in FIG. 3, and the fan motor 3 stops. Also, the output 03 of the comparator 19
On the other hand, the transistor 32 of the compressor motor drive relay circuit 22 is turned off via the AND circuit 26, and as shown in FIG.
1 As shown in the figure, the compressor motor relay contact 6 is turned off and the compressor motor 5 is stopped.

Further, the output 03 of the comparator 19 sends a reset signal from the reset forming section 24 as shown in FIG. 2, and the output 02 is changed to the L level as shown in FIG.
1 to its initial state. Next, it is assumed that the temperature inside the refrigerator becomes higher than the set value again at T4 o'clock.

At this time, as in the case of T, above, FIG.
The operation is as shown in 8. That is, fan motor 3
is driven, and the other output of the timer circuit 21 is set to the daily level by the trigger signal of the timer set. As this state continues, that is, the fan motor 3 rotates to equalize the temperature inside the refrigerator, the delay time L-
It is assumed that L-T4 reaches T2-T at T5 before T, and the temperature inside the refrigerator becomes lower than the set value. At this time,
In FIG. 3, the question "Is the timer up?" is NO, and the combustor motor 5 is not turned on, returning to the initial state.

More specifically, at T5, the output 03 of the comparator 19 changes from the daily level to the L level as at T3, and as a result, the fan motor relay contact 4 also changes from on to off, and the fan motor 3 stops. However, when the output 03 of this comparator 19 goes from H level to L level at T3 before the delay time T2-T has elapsed, a reset signal is sent to the timer circuit 21, and its output 02 remains at L level, and the The transistor 32 of the breather motor drive relay circuit 22 is not turned on. Therefore, the compressor motor relay contact 6 remains in the off state and the compressor motor 5 is not driven. In the above embodiment, it goes without saying that the fan motor 3 inside the refrigerator is not operated when the door is open.

In the above embodiments, the case of a refrigerator has been described, but the present invention is not limited to this, and can also be applied to other general refrigeration devices such as a freezer compartment, a refrigerator, and a freezer showcase.

As described above, in the case where the temperature of the detection part inside the refrigerator becomes higher than the set value, the fan motor inside the refrigerator is first driven for a certain period of time to equalize the temperature inside the refrigerator, and even at that time, the detection part is still detected. The compressor motor is driven only when the part temperature is high.

Therefore, compared to the conventional case where the compressor motor is driven immediately when the local temperature near the detection unit becomes higher than the set value, the compressor motor is driven to the minimum necessary and is driven more than necessary. This has the advantage that unnecessary power consumption can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of a control circuit of a refrigeration system showing an embodiment of the present invention, FIG. 2 is a waveform diagram of each part of FIG. 1, and FIG.
The figure is a flowchart for explaining the operation of the present invention. 1...Commercial power supply, 2...Switch, 3
...Fan motor, 4, 6...Relay contact, 5
...Compressor motor, 7...Transformer, 8...
・Full-wave rectifier, 9... Stabilization circuit, 10, 11
......Capacitor, 12...DC power supply terminal,
13... Control circuit, 14... Temperature detection circuit, 15... Thermistor, 16, 17, 18
, 27, 28, 29, 30...Resistance, 19...
... Comparator, 20, 22 ... Drive relay circuit, 21 ... Delay timer circuit, 23 ...
...Set signal forming section, 24...Reset signal forming section, 25...Time setting section, 26...AND circuit, 31, 32...Transistor, 33, 34...Relay coil , 35, 36...diode. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A refrigeration system having a fan motor for stirring cold air and a compressor motor for compressing refrigerant is provided with a temperature detection circuit that outputs an output when the detected temperature rises above a predetermined value, and this temperature detection circuit has the A control circuit for a refrigeration system, characterized in that a relay circuit for driving a fan motor is connected thereto, and a relay circuit for driving the compressor motor is connected to the temperature detection circuit via a delay timer circuit. 2. The refrigeration system according to claim 1, wherein the temperature detection circuit includes a negative characteristic thermistor for detecting the internal temperature, a variable resistor for temperature setting, and a comparator for comparing and outputting the output voltages of these. control circuit. 3. Relay circuits for driving the fan motor and compressor motor each have relay contacts connected in series to the fan motor and compressor motor, respectively, and the excitation coils of these relay contacts are connected to the direct output of the temperature detection circuit. The control circuit for a refrigeration system according to claim 1 or 2, wherein the control circuit is configured to perform control using a delayed output of a timer circuit. 4. The delay timer circuit according to claim 1, 2 or 3, wherein the delay timer circuit includes an AND circuit for obtaining an AND output between the output of the timer circuit and the output of the temperature detection circuit. Refrigeration equipment control circuit.