JPS5895990A - Safety controller for refrigerating cycle - Google Patents

Abstract

PURPOSE:To prove the safe operation control against an abnormal state by providing a voltage check circuit which checks the voltage applied to a compressor and feeding back the check signal to a controller. CONSTITUTION:When an operation switch SW is closed, a cycle solenoid vlave EV and an outdoor fan are energized. After the start stabilizing time is elapsed, a control relay CR is energized, thereby supplying an electric power to a compressor C0. Thereafter, the power supply to the compressor C0 is controlled by the ON or OFF of an indoor thermostat TH. When an overheat relay OHR, an overcurrent protection relay OCR or a pressure switch PSH is operated during the operation to cause the power supply to the compressor C0 to be stopped, a signal is outputted from a photocoupler FT forming a voltage check circuit, thereby allowing a microcomputer 1 to safely control the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety system for monitoring the operation of a compressor in a refrigeration cycle such as a heat pump heating/cooling system.

A conventional compressor safety device will be explained with reference to FIG. Reference numeral 1 denotes a microcomputer which is in charge of control, and inputs signals from an operation switch 3 constituted by an operation switch SW, etc., a room temperature sensor T)I, and an input circuit 4 via an input interface 2. Also, via the output interface 5, control signals for the compressor CO1, the outdoor fan FO, the refrigeration cycle solenoid valve EV, and the indoor fan FA are output.

FIG. 2 shows the power circuit around the compressor 00. CR
is a control relay driven by the control signal from the microcomputer 1 (Y). 6 is a safety switch, which is composed of the following three types 42. 01 (R is the compressor C
This is an overheat protection relay that detects O different layer overheating. OCR
is an overcurrent protection relay that detects overcurrent flowing through the combination L/]f CO. PSI is a pressure switch that detects overpressure of the refrigerant compressed by the compressor CO.

In this configuration, when the operation switch SW is turned on at the time of TONI, which will be explained using the time chart of FIG. 2 showing the control operation, the cycle solenoid valve EV
and the outdoor fan is turned on.

The compressor CO is turned on after the stabilization time T for startup has elapsed.
Do N. This stabilization time T is a time necessary for stabilizing the pressure of the refrigerant cycle and stabilizing the bolt starter for starting the compressor CO, etc. Next, when the indoor thermostat TI (turns off at T OFF, the solenoid valve EV compressor CO stops.Next, when the indoor thermostat turns on at TON2, which is within the stabilization time T, the compressor CO It does not turn on at the time of TON2, but turns on after the stabilization time T has elapsed.The above operation indicates a normal operation.

Next, the operation when an abnormal situation occurs will be explained.

TA is overheat protection relay OHR and overcurrent protection relay OCR.
This indicates that the safety switch 6 such as the pressure switch PSH or the like has detected an abnormality and the contact has opened.

At this time, the power supply to the compressor CO is cut off, so the compressor CO stops. However, since the microcomputer 1 does not detect any abnormality, the restriction relay CR remains in the ON state.

Next, n indicates the point in time when the safety switch 6 is reset manually or naturally.At this point, the control relay CR
Since it is in the ON state, power is supplied to the compressor CO, and the compressor CO starts to start up. However, the compressor CO is over 1! The flow protection relay OCR etc. may be activated and the different layer will stop at TA2. The above abnormal operation will occur in TB2 unless the operation switch SW is turned off. It is repeated as shown in TAa. As described above, a situation arises in which safety cannot be maintained due to the control operation of the compressor.

SUMMARY OF THE INVENTION An object of the present invention is to perform safety control for an abnormal situation when an abnormality occurs in a compressor.

Conventional safety protection devices for compressors include overcurrent protection relays and pressure switches, but they all cut off the voltage supply to the compressor, and the safety control is implemented when the safety protection device is restored. Not considered. The present invention focuses on this point.

In other words, if some kind of safety protection device is activated and the power supply to the compressor is cut off, the disconnection of the power supply is detected and fed back to the control device, thereby ensuring safe driving control for different jockey conditions. Hereinafter, the present invention will be explained by way of an example based on four factors. 7
is a voltage check circuit that checks the supply voltage applied to the compressor CO.

The signal from the voltage check circuit 7 is fed back to the input interface 2 and further communicated to the microcomputer 1. ALM is an alarm device and is controlled by the microcomputer 1 via an output interface. The other configurations are the same as the conventional FIG. 1.

Next, we will explain the details of the power circuit around the compressor 00 shown in Fig. 5. FT is a photocoupler,
It detects the voltage applied to the compressor CO via the resistors R1, R2 and the diode Di. R3
is the output load resistance of the photocoupler FT, and its output signal is input to the input interface 2. The other configurations are the same as the conventional one shown in FIG.

In this configuration, the control operation will be explained using the time chart shown in Figure 6. The operation from the ON time point TONI of the start switch SW to the time point TA when an abnormal situation occurs is the normal operation range and is the same as the conventional one. The time point TA indicates a case where the safety switch 6 senses an abnormality and the contact opens. At this time, the power to the compressor CO is cut off, so the compressor CO stops. At the same time, the photocoupler FT forming the voltage check circuit detects that the power supply to the compressor CO is cut off. This detection signal is input to the microcomputer 1 via the input interface 2. At this time, the microcomputer 1 checks the time width t of the treatment as a check timing for power-off, and if the power-off continues for more than the time width t, it is regarded as abnormal and the control operation is restarted from the point of π. That is, after the startup stabilization time T of the compressor CO has elapsed, voltage is applied to the compressor CO to restart it. At this time, if an abnormal situation occurs again at TA2, the microcomputer determines that the compressor CO is completely abnormal, outputs an alarm ALM, and stops the entire system. As described above, safe operation and sterilization against abnormalities in the compressor CO is ensured.

The above operations can be easily performed using a microcomputer.

As described above, the present invention is provided with a voltage check circuit that checks the voltage applied to the compressor, and feeds back the check signal to the control device to control the compressor. On the other hand, if the safety protection device is activated and the power to the compressor is cut off, safe operation control can be carried out.

[Brief explanation of drawings]

Figure 1 shows the configuration of a conventional refrigeration cycle control device.
The figure is a system diagram of a power circuit of a conventional control device, FIG. 3 is an operation flowchart of a conventional control device, and FIG. 4 is a diagram of a safety control device for a refrigeration cycle according to an embodiment of the present invention. Cause, 5th
The figure is a system diagram of a power circuit according to an embodiment of the present invention, and FIG. 6 is an operation flowchart of an embodiment of the present invention. 1...Microcomputer CO...Compressor 6
... Safety protection device 7 ... Voltage check circuit F
T...Photocabra 2fJ 3FB &t rorr rotvz Ts rt
t r/@z k 1sst4 figure

Claims (1)

[Scope of Claims] 1. In a control device for controlling a compressor of a refrigeration cycle, the compressor (2) is provided with a voltage check circuit for checking the presence or absence of an applied voltage, feeds back the check signal to the control device, and controls the compressor (2). A safety control device for a refrigeration cycle, characterized in that the voltage is controlled by the voltage check circuit (Claim 1). A safety control device for a refrigeration cycle, characterized in that, when detected, the control operation of the system is restarted from an initial state by feedback to a control device.3. 1. A safety control device for a refrigeration cycle, characterized in that the refrigeration cycle is configured to be able to be restarted a predetermined number of times, and to stop the refrigeration cycle after the predetermined number of times.