JPS647550Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a relay control circuit that controls energization of a relay according to the output of a bistable multivibrator.

This type of relay control circuit is suitable, for example, for a heat pump heating system that controls the capacity of a compressor.
In this case, at the beginning of operation, the bistable multivibrator is operated in one direction so that the compressor has a large capacity, and after the room temperature reaches a preset temperature, the bistable multivibrator is operated in one direction so that the compressor has a small capacity. It is desired to operate the vibrator in the opposite direction and maintain this state until the operation is stopped. By the way, if the bistable multivibrator is always connected to a DC power supply, a trigger circuit for setting the initial state synchronized with the operation signal is required to ensure that the bistable multivibrator operates in one direction at the beginning of operation, which increases the cost. It had the disadvantage that it became high.

The present invention was created in view of the above facts, and is designed to allow initial settings of the bistable multivibrator to be made without using a complicated trigger circuit when the bistable multivibrator is constantly connected to a DC power source. The purpose is to provide a relay control circuit.

Hereinafter, an embodiment of the present invention will be described by applying it to a heat pump heating device. In Fig. 1, 1 and 2 are bus bars to which DC power (not shown) is supplied;
and 4 are a resistor and a constant voltage element connected in series between the bus bars 1 and 2, 5 is a bistable multivibrator installed in parallel with the constant voltage element 4, and a resistor 6, a reverse current blocking diode 7 and an NPN transistor 8 are connected in series. circuit, a series circuit of resistor 9 and NPN transistor 10, a series circuit of resistors 12, 13 and 14 between connection point 11 of resistor 6 and diode 7 and bus bar 2, and connection of resistor 9 and the collector of transistor 10. Resistors 16, 17 and 1 between point 15 and busbar 2
The connection point 19 of the resistors 17 and 18 is connected to the base of the transistor 8, and the resistor 1 is connected to the base of the transistor 8.
No. 3 and 14 connection points 20 are connected to the base of the transistor 10, respectively. The resistance values of the bistable multivibrator 5 are determined so that the transistor 8 is turned on and the transistor 10 is turned off when initially energized. Reference numeral 21 indicates an operation switch as a switch means inserted into the bus bar 1, 22 and 23
24 and 25 are base bias resistors of the transistor 22, and one end of the bias resistor 24 is connected to the emitter of the transistor 22. and resistance 2
A connection point 26 between the transistors 4 and 25 is connected to the base of the transistor 22, and the other end of the resistor 25 is connected to a connection point 27 between the diode 7 and the collector of the transistor 8, which is the output point of the bistable multivibrator 5. Blower control relays 29 and 30 are compressor control relays and NPN transistors connected in series between bus bars 1 and 2 via operation switch 21; ,
31 is a high-voltage thermo-on "H" of a thermo device (not shown) that compares the temperature of the air-conditioned room with a set value.
An input terminal to which a low-voltage thermo-off "L" signal is supplied, and the input terminal 31 is connected via a trigger generator 32 that issues a positive trigger signal when the thermo signal changes from "H" to "L". Connection point 33 of resistors 12 and 13 of bistable multivibrator 5
and bias resistors 34, 35
It is connected to bus bar 2 via. The connection point 36 between the bias resistors 34 and 35 is connected to the transistor 3.
0 base.

FIG. 2 shows a heat pump heating system to which the present invention is applied, including a compressor 37, a user-side heat exchanger 38,
A refrigerant circuit 41 is formed in which a pressure reducing device 39 and a heat source side heat exchanger 40 are connected in an annular manner. Also, 42
is a bias circuit that returns part of the refrigerant to the suction port during the compression process of the compressor 37, and a solenoid valve 43 is inserted therein. In addition, 44 is a heat exchanger 38, 40
This is a blower that promotes heat exchange.

Thus, when DC power is applied between the bus bars 1 and 2 for the first time, the bistable multivibrator 5 has the transistor 8 turned on and the transistor 10 turned off. When the operation switch 21 is turned on, the base bias of the transistor 22 is turned on by the bias resistors 24 and 25 because the transistor 8 of the bistable multivibrator 5 is turned on, and the solenoid valve control relay 23 is energized.
Further, when the blower control relay 28 is energized and the thermo-on signal "H" is supplied to the input terminal 31, the transistor 30 is base biased and turned on, and the compressor control relay 29 is energized.

In this manner, in the heat pump heating apparatus, the blower 44 and the compressor 37 are started by energizing the control relays 28 and 29, and the solenoid valve 43 is closed by energizing the control relay 23. Therefore, the refrigerant discharged from the compressor 37 performs a condensing action in the heat exchanger 38 on the user side, heats the indoor air circulated by the blower 44, is depressurized in the pressure reducer 36, and is further transferred to the heat source side. After performing evaporation in the exchanger 4 and absorbing heat from the outdoor air, the air returns to the compressor 37, and this process is repeated. Also, the solenoid valve 4 of the bias circuit 42
3 is closed, the discharge capacity of the compressor 37 is large, the heating capacity of the utilization side heat exchanger 38 is large, and the room temperature is rapidly raised.

When the room temperature exceeds the set value, the thermo-off signal "L" is supplied to the input terminal 31, and the bistable multivibrator 5 receives a positive trigger signal from the trigger generator 32 to the connection point 33, and the transistor 10 When transistor 8 is turned on, transistor 8 is turned off, resulting in stable operation due to mutual positive feedback. Therefore, the base bias of the transistor 22 is released and the transistor 22 is turned off, and the solenoid valve control relay 23
The solenoid valve 44 of the bias circuit 42 is de-energized.
3 opens. On the other hand, the base bias of the transistor 30 is also released and turned off, and the compressor control relay 29 is de-energized and the compressor 37 is stopped.
Therefore, the heat pump heating device suspends the heating operation and performs only the air blowing operation using the blower 44.

Thereafter, when the room temperature falls below the set value again, a thermo-on signal "H" is supplied to the input terminal 31, the transistor 30 is turned on, the control relay 29 is energized, and the compressor 37 is restarted. At this time, the solenoid valve 43 is already open, and the discharge capacity of the compressor 37 is reduced by the operation of the bias circuit 42, so the heating capacity of the utilization side heat exchanger 38 is small.
Economical heating operation will be performed.

From then on, when the thermo signal at the input terminal 31 changes from "H" to "L", the compressor 37 stops, and when it changes from "L" to "H", the compressor 37 starts, and this repeats. The stable multivibrator 5 is not affected by the positive trigger signal supplied from the trigger generator 32, and keeps the transistor 8 off and the transistor 10 on, thereby opening the solenoid valve 43. The heat pump heating device intermittently performs heating operation with a small discharge capacity of the compressor 37 until the operation switch 21 is released, and maintains the room temperature near the set temperature.

When the operation switch 21 is opened, the bistable multivibrator 5 returns to the initial state in which the transistor 8 is on and the transistor 10 is off as follows. That is, when the operation switch 21 is open, the bus bar 1 - resistors 3 and 6 - diode 7 - gate bias resistors 25 and 24 - blower control relay 28 -
Current flows in the path of bus 2, and at this time, connection point 1
By making the voltage at the connection point 20, which divides the voltage generated at the transistor 1, extremely low, the transistor 10 is turned off and the transistor 8 is turned on. In this way, when the bistable multivibrator 5 is supplied with DC power between the bus bars 1 and 2,
Alternatively, if the operation switch 21 is opened while DC power is being supplied between the bus bars 1 and 2, the initial state is returned to where the transistor 8 is on and the transistor 10 is off, and when the operation switch 21 is first turned on, the electromagnetic The valve control relay 23 is energized and the heat pump heating device performs heating operation with a large heating capacity, and then when a positive trigger signal is input from the trigger generator 32, the transistor 8 is turned off and the transistor 10 is turned on, and heating is started. This switches to heating operation with low capacity.

As mentioned above, the present invention includes a bistable multivibrator that operates in one direction when energized and operates in the opposite direction when supplied with an input signal, and a series circuit of a switching means, a transistor, and a relay, which are connected to a DC power source. A bias resistor is connected to the base of the transistor and the output point of the bistable multivibrator is connected, and an impedance element is connected in parallel to the transistor and the relay, so that when the switch means is opened, the bias resistor and the output point of the bistable multivibrator are connected. Since the current flowing through the impedance element is used to return the bistable multivibrator to one direction, when the bistable multivibrator is constantly connected to a DC power supply, a complicated trigger circuit is not required, and the transistor The bistable multivibrator can be initialized using a bias resistor and an impedance element such as a relay whose energization is directly controlled by the switch means, and can be constructed at an extremely low cost. It is suitable for heat pump heating equipment that requires relay control by unidirectional operation of a bistable multivibrator.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram showing an embodiment of the present invention;
FIG. 2 is a refrigerant circuit diagram of a heat pump heating device to which the present invention is applicable. 5...Bistable multivibrator, 21...Operation switch (switch means), 22...Transistor,
23... Solenoid valve control relay, 24, 25... Bias resistance, 27... Connection point (output point), 28... Blower control relay (impedance element).

Claims (1)

[Scope of utility model registration request] This circuit consists of a bistable multivibrator circuit that is connected between the power bus bars so that current is always supplied, and whose output is set in one direction when the power is turned on, and whose output is switched in the opposite direction when an input signal is supplied. A diode connected between an output transistor and a resistor provided on the load side of this transistor, a relay driving transistor connected to the output terminal of the circuit, and a connection between the base terminal of this transistor and one of the power supply bus bars. A bias resistor connected between the two, a switch inserted into the power bus to control the power supply to the bias resistor, and a relay connected between the power bus at the position where the power supply is controlled by this switch. When the switch is open, the output of the bistable multivibrator is switched to one side by the current flowing from one side of the power bus through the resistor diode, the bias resistor, and the excitation winding of the relay to the other side of the power bus. A relay control circuit characterized in that a bias constant of a bistable multivibrator is set so as to return to normal state.