JPS5885044A - Overload control device for air conditioner - Google Patents

Abstract

PURPOSE:To make a bypass circuit for controlling the overload unnecessary and simplify the construction of a refrigerating cycle by a method wherein the overload control upon room heating operation and room heating touch defrosting operation is effected by the control of starting and stopping of an outdoor fan. CONSTITUTION:Upon the room heating operation, the flow of a refrigerant medium is recirculated through a compressor 21, a four-way valve 12, a first indoor heat exchanger 26, a two-way valve 28 for dehumidifying, the second heat exchanger 25, a pressure reducer 24 and an outdoor heat exchanger 23 sequentially. In this case, the outputs of respective transistor invertors (INV) 8-10 are H, L, L, respectively normally wheh the condition of a pressure switch 3 is as shown by the diagram, therefore, an outdoor fan motor 14 is rotated. Next, when it is turned into the overload condition, the contact piece 3a of the pressure switch 3 is switched to the side of a high-pressure contact 3c and said motor 14 is stopped. On the other hand, upon the room heating mode dehumidifying operation, the refrigerant medium flows as shown by the broken line arrow sign and the outputs of respective INV 8-10 are L, H, L, respectively, therefore, the fan motor 14 is controlled by a procedure in reverse to the above-described procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overload control device for an air conditioner having cooling, heating, and dehumidification functions, which stops an outdoor fan when heating is overloaded, and shuts down an outdoor fan when heating or dehumidification is overloaded. One of the purposes is to simplify the refrigeration cycle and enable overload control by operating the fan.

Overload control for air conditioners, which generally have cooling, heating, and dehumidification functions, is detected by a pressure switch installed on the high-pressure side during the refrigeration cycle, and the bypass valve in the refrigeration cycle is opened and closed to change the high-pressure side to low pressure. This is a moxibustion mode (hereinafter referred to as heating) that stops the outdoor fan and makes the cold air blown from the air conditioner a little higher, especially during heating and dehumidifying operation. (referred to as "slight dehumidification") requires some kind of overload control, and conventionally a bypass circuit mainly having a bypass valve has been provided in the refrigeration cycle.

Hereinafter, a conventional overload control circuit will be explained with reference to FIGS. 1 to 3 of the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a DC low voltage circuit, which is comprised of various relays and electronic components, which will be described later, for controlling an air conditioner. 2 is a DC power supply, which is connected to the common contact 3b of the pressure switch 3. The inside of the pressure switch 3 is connected from the common contact 3b to the low pressure contact 3d via the contact piece 3a, and when the pressure on the high pressure side during the refrigeration cycle reaches the set value of the pressure switch 3, the contact piece 3
a is connected to the high voltage contact 3G. Further, the low voltage contact 3d is connected to a transistor inverter 8 via a relay coil 4 for stopping the outdoor fan. Furthermore, the high voltage contact 3C is a bypass relay coil 6.
connected to ground via. Further, the dehumidifying two-way valve relay coil 6 is connected to the DC power supply 2, the narrow path terminal is connected to the transistor inverter 9, and the four-way valve relay coil 7 is also connected to the DC power supply 2.

FIG. 2 shows a sequence circuit for controlling the load of an air conditioner. In the figure, 16 is an AC power source, and the DC low voltage circuit 1 is connected in parallel.

One end of the dehumidifying two-way valve coil 11 is connected to the AC power supply 16, and the narrow path terminal is connected to the dehumidifying two-way valve relay contact 6a.
It is connected to a different polarity of the AC power source 16 via the AC power source 16. Also, from the AC power supply 16 to the four-way valve relay contact 7! 4-way valve coil 12 and bypass 2-way valve coil 1 via L
3, and the reverse terminal of the four-way valve coil 12 is connected to the outdoor fan stop relay contact 4a via the contact part of the dehumidifying two-way valve relay contact 6a and the bypass relay contact 6a.
It is connected to the open contact portion 4b of. In addition, the AC power supply 1
5 to outdoor fan motor 14(7)-11? J is connected, and the narrow path terminal is the outdoor fan stop relay contact 4a.
It is connected to a different polarity of the AC power source 16 via the AC power source 16.

In the above configuration, the transistor inverter 8°9.1
0 is the transistor inverter input signal 8! L, 9IL
, H signal to 101L (voltage of DC power supply 2)
When this happens, the transistor output signals 8b and 9
An L signal (or OV lightning voltage) appears on b and 10b, and a potential difference is generated in the outdoor fan stop relay coil 4, the dehumidification relay coil 6, and the four-way valve relay coil 7, and they are excited. That is, In the conventional circuit, signals during heating and warm dehumidification are controlled by the combination shown in FIG.

Therefore, during heating, the dehumidifying two-way valve relay coil 6
The 4-way valve relay coil 7 is energized, and the outdoor fan stop relay coil 4 and the 2-way dehumidifier relay coil 6 are energized during warm dehumidification. Furthermore, when the pressure switch 3 is operated due to overload, the circuit of the outdoor fan stop relay coil 4 is disconnected, so the outdoor fan stop relay coil 4 is not always energized and the bypass relay coil 6 is not energized. The circuit is activated (opened).

In the case of this conventional circuit, during normal operation of warm air dehumidification,
Since the outdoor fan stop relay coil 4 is excited, the outdoor fan motor 14 is stopped.

In the event of overload, the outdoor fan motor 14 is operated by the operation of the pressure switch 3. However, in the case of this system, since the bypass relay coil 6 is also excited at the same time as the pressure switch 3 is operated during overload, there is a drawback that electricity is wasted.

Furthermore, when the pressure switch 3 operates during heating overload, the bypass relay coil 6 is energized and the bypass relay contact 61L is operated, which causes the bypass valve in the refrigeration cycle to operate and perform overload control. However, control during heating overload requires a bypass valve and a relay to control the bypass valve in the refrigeration cycle, which is very expensive and has the disadvantage of complicating the refrigeration cycle.

The present invention eliminates the drawbacks found in the above-mentioned conventional circuit structures.

Hereinafter, FIGS. 4 to 4 of the accompanying drawings showing one embodiment of the present invention.
This will be explained with reference to FIG. Here is Figure 1.

Components that are the same as those in FIG. 2 are given the same numbers and their explanation will be omitted.

First, the basic structure of the refrigeration cycle will be explained with reference to FIG.

In the figure, 21 is a compressor, 12 is a four-way valve that switches between cooling and heating, 23 is an outdoor heat exchanger, 24 is a pressure reducer,
26 is an indoor first heat exchanger, 26 is an indoor second heat exchanger,
A refrigerant circulation circuit is constructed by connecting these in an annular manner. Here, a dehumidifying bypass two-way valve 11 is connected in parallel to the pressure reducer 24, and a dehumidifying two-way valve 28 is connected between the indoor first heat exchanger 26 and the indoor second heat exchanger 26. A parallel circuit consisting of a cooling pressure reducer 22 is provided. 14 is an outdoor fan motor, 27 is an indoor fan motor, and 3 is a pressure switch.

The refrigeration cycle with the above configuration shows the basic structure.
If necessary, a check valve or the like (none of which is shown) is separately provided.

Next, a schematic electric circuit will be explained with reference to FIGS.

It is comprised of various relays and electronic components that will be described later to control the air conditioner. Reference numeral 4 denotes a relay coil for stopping the outdoor fan, which is connected to the DC power supply 2, and whose narrow terminal is connected to the common contact 3b of the pressure switch 3. This low voltage contact 3d is connected to a transistor inverter 8. The single high voltage contact 3C is connected to the connection between the four-way valve relay coil 7 and the transistor inverter 9.

Further, the DC low voltage circuit 16 is connected in parallel with the AC power supply 15 as shown in FIG. The circuit configuration shown in FIG. 6 is similar to the bypass two-way valve coil 1 shown in FIG. 2, which shows a conventional circuit.
3 and bypass relay coil contact 5 and open contact part 4
This is the circuit without b.

Further, the signal combinations of the output signals 81L, 9N, and 102L of each transistor inverter 8, 9, and 10 are the same as in FIG.

Here, the circuit shown in Fig. 6 and Fig. 6 shows only the parts necessary for overload control.
The control circuit for the motor 27, the two-way dehumidifying valve 28, and the operation switching paths for cooling, heating, and dehumidification will not be described because they are not directly related to the gist of the present invention and may be conventionally known circuits. are doing.

- In the configuration shown in F, the flow of refrigerant during cooling operation is as shown by the solid line arrow in FIG. , cooling pressure reducer 22, indoor second heat exchanger 26, four-way valve 12,
It circulates with the compressor 21.

In addition, the flow of refrigerant during heating operation is as shown by the broken line arrow in the same figure.
, two-way dehumidifying valve 28, indoor second heat exchanger 26, pressure reducer 2
4. The outdoor heat exchanger 23 circulates through the four-way valve 12 and the compressor 21.

Furthermore, the flow of refrigerant during dehumidification operation is basically the same as during cooling, as shown by the dashed-dotted line arrow in the figure.
4-way valve 12, outdoor heat exchanger 23, dehumidification bypass 2-way
yPll, indoor first heat exchanger 26, cooling pressure reducer 22,
It circulates through the indoor second heat exchanger 26, the four-way valve 12, and the compressor 1.

Normally during heating operation, the pressure inlet 3 is in the state shown in FIG. 6, and the input signals 81L, 9a10IL of each transistor inverter 8, 9, 10 are in the state shown in FIG. 3, respectively. Therefore, the outdoor fan motor 14 is rotating.

When an overload condition occurs, the contact piece 3a of the pressure gas inlet 3
is switched from the low voltage contact 3d to the high voltage contact 3C, and the transistor inverter 90 input signal 9& is at L, so the outdoor fan stop relay coil 4 is energized and the outdoor fan motor 14 is stopped.

Further, during warm air dehumidification operation, the pressure switch 3 is normally in the state shown in FIG.

9! L and 10a are in the state shown in FIG. 3, respectively.

Therefore, the outdoor fan motor 14 is in a stopped state.

When an overload condition occurs, the contact piece 3a of the pressure switch 3
switches from low voltage contact 3d to high voltage contact 3C,
Since the input 9a of the raster inverter 90 is H, the outdoor fan stop relay coil 4 is no longer excited, and the outdoor fan motor 14 rotates. This outdoor fan motor 1
Rotation 4 reduces the pressure on the high pressure side and eliminates the overload.

Therefore, overload during heating operation and warm air method dehumidification operation can be achieved by starting and stopping the outdoor fan motor 14, so there is no need to provide a bypass valve for overload control in the refrigeration cycle as in the past. , the structure of the refrigeration cycle can be simplified and the cost can be reduced. Furthermore, the electric circuit does not require any portion related to the bypass valve, and a simple control circuit is required.

As is clear from the above embodiments, the overload control device for an air conditioner according to the present invention performs overload control during heating operation and during heating dehumidification operation by controlling the operation of the outdoor fan. There is no need to provide a bypass circuit for overload control in the refrigeration cycle, simplifying the structure of the refrigeration cycle, and eliminating the need for an electric circuit to control the bypass circuit, simplifying the electric circuit configuration and making it cheaper. It has various advantages, such as being able to create

[Brief explanation of the drawing]

Fig. 1 is a DC low voltage circuit diagram configuring a conventional air conditioner overload control device, Fig. 2 is a sequence circuit diagram configuring the same control device, and Fig. 3 is a diagram showing various components in the same DC low voltage circuit. An explanatory diagram showing the input mode of a transistor inverter, FIG. 4 is a refrigeration cycle diagram of an air conditioner equipped with an overload control device according to an embodiment of the present invention, and FIG. 6 is a DC low voltage circuit configuring the same control device. 6 are sequence circuit diagrams configuring the control device. 3...Pressure switch, 4...Relay coil for stopping outdoor fan, 41L...IJ relay contact for stopping outdoor fan, 8, 9...Transistor inverter , 7... Relay coil for 4-way valve, 1
2...4-way valve, 14...Outdoor fan motor, 21...Compressor, 23...Outdoor heat exchanger, 24...・Pressure reducer, 25...
Indoor first heat exchanger, 26... Indoor second heat exchanger. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4

Claims (1)

[Claims] A compressor, an air conditioning/heating switching valve, a first indoor heat exchanger, a second indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger are each connected in a ring to form a heat pump refrigeration cycle, and this refrigeration cycle a switching valve device that switches cooling operation to dehumidification operation; a pressure switch that detects the pressure within the refrigeration cycle and turns it on and off; and an indoor fan that ventilates each heat exchanger on the indoor side; An outdoor fan is provided to provide ventilation to the outdoor heat exchanger, and a control device is provided to control the operation of the outdoor fan by turning on and off the pressure switch. Stop the outdoor fan,
The outdoor fan is operated when the pressure switch detects an overload of the compressor, and the outdoor fan is normally operated during heating operation, and when the pressure switch detects an overload of the compressor. An overload control device for an air conditioner that operates the outdoor fan.