JP3933542B2 - Single phase induction motor controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a single-phase induction motor. In particular, the present invention relates to a control device for a single-phase induction motor that drives a compressor.
[0002]
[Prior art]
FIG. 7 shows a schematic circuit configuration example of a conventional single-phase induction motor control device. One end of the AC power supply 22 is connected to one end of the overcurrent relay (OCR) 14 via the relay switch RL1a. The other end of the overcurrent relay 14 is connected to a single-phase induction motor 15. The single-phase induction motor 15 has a main winding L1 and an auxiliary winding L2, and one end of the main winding L1 and one end of the auxiliary winding L2 are connected to the other end of the overcurrent relay 14.
[0003]
The other end of the main winding L1 is connected to one end of the operating capacitor Cr, one end of a current limiting resistor Rs (hereinafter referred to as resistor Rs), and one end of a relay switch RL4a. The other end of the auxiliary winding L2 is connected to the other end of the operating capacitor Cr and one end of the starting capacitor Cs. The other end of the starting capacitor Cs is connected to one end of the relay switch RL3a. The other end of the resistor Rs, the other end of the relay switch RL4a, and the other end of the relay switch RL3a are connected in common and connected to the other end of the AC power supply 22.
[0004]
The control circuit 23 performs on / off control of the relay switches RL1a, RL3a, and RL4a. The control circuit 23 turns on the relay switches RL1a and RL3a and turns off the relay switch RL4a when starting the compressor. Then, the control circuit 23 turns on the relay switch RL4a and turns off the relay switch RL3a after the compressor has started normally.
[0005]
Recently, a microcomputer (hereinafter referred to as a microcomputer) is used as a part of the control circuit 23, and the microcomputer has started normally based on the current value flowing through the single-phase induction motor or the like. There is a commercialized product that detects whether it has failed and performs a control to try to start the compressor again after an appropriate time if the compressor fails to start.
[0006]
[Problems to be solved by the invention]
The control device for the single-phase induction motor of FIG. 7 is configured so that, for example, a voltage that is ½ of the voltage output from the AC power supply 22 is applied to both ends of the resistor Rs when the compressor is started. Limit the current value at. Then, if the voltage applied to the main winding L1 of the compressor is reduced to ½ of the voltage output from the AC power source 22, it is difficult to start the normal compressor. By additionally connecting a capacitor Cs, the electrical phase shift between the main winding L1 and the auxiliary winding L2 is increased, and the starting torque is increased to compensate for the startability of the compressor.
[0007]
Here, the voltage output from the AC power supply 22 is 240V, and the compressor for the air conditioner driven by the single-phase induction motor has a refrigerating capacity of about 2.5 horsepower (= 1.865 [kW]). In the case of a compressor, the power consumption in the resistor Rs is about 4 [kW] for a short time when the compressor is started. Since the energization time of the resistor Rs at the time of starting the compressor is about 0.2 seconds to 0.3 seconds, a resistor Rs having a rated power of several tens [W] is used under the condition of energizing for a short time. .
[0008]
When the compressor fails to start, the control circuit 23 turns off the relay switches RL1a, RL3a, and RL4a and stops the operation of the control device for the single-phase induction motor.
[0009]
However, for example, when the relay switch RL1a is welded, the relay switch RL4a is off even if the operation of the control device for the single-phase induction motor is stopped, so the AC power supply 22 → the main winding L1 → the resistance Rs → AC Since the closed circuit of the power source 22 is formed, current continues to flow through the resistor Rs, and the resistor Rs generates heat and is in a dangerous state.
[0010]
By the way, various causes can be considered as a cause of failure in starting the compressor driven by the single-phase induction motor. For example, because the compressor installed in the air conditioner has not passed enough time since the last stop, the refrigeration cycle is not balanced between high and low pressures, or because it has not been used for a long time It is conceivable that the start-up failure, the voltage output from the AC power supply 22 is abnormally low, or the relay switch RL1a does not operate normally due to a failure of the control circuit 23 or the relay switch RL1a.
[0011]
Further, an abnormality may occur during the operation of the compressor, and the operation of the compressor may be stopped. This can be caused by various causes. For example, when an instantaneous power failure occurs in the AC power source 22, the voltage output from the AC power source 22 decreases, the heat exchange in the heat exchanger deteriorates, and the compressor overcurrent relay 14 operates, There are cases where the control device of the single-phase induction motor fails.
[0012]
However, it is difficult for the control device for the single-phase induction motor of FIG. 7 to specify the cause of the failure when such a failure such as a compressor start failure or an abnormal stop occurs. Therefore, it took time to repair the defective part during production or service.
[0013]
The control device for the single-phase induction motor of FIG. 7 includes an instantaneous power failure detection circuit (not shown). The instantaneous power failure detection circuit generates an AC power supply synchronization pulse signal that is inverted every zero crossing of the voltage output from the AC power supply 22, and outputs the AC power supply synchronization pulse signal to the control circuit 23. In general, the control circuit 23 determines an instantaneous power failure when several pulses are missing in consideration of the influence of noise, and stops the start or operation of the compressor.
[0014]
In the event of an instantaneous power failure of the AC power source 22, if the AC power source 22 recovers before the control circuit 23 detects the instantaneous power failure, the restart will usually fail to restart the compressor in normal operation. Become. At that time, since the relay switch RL4a is on, a large current flows through the main winding L1 of the single-phase induction motor 15.
[0015]
Further, in the above-described instantaneous power failure detection circuit, the AC circuit 22 described above in the control circuit 23 is caused by a decrease in the output voltage of the AC power supply 22 caused by a large current at the time of starting the compressor or a disturbance in the output voltage waveform of the AC power supply 22. An error occurred when reading the power supply synchronization pulse signal. Note that this reading error tends to easily occur when a compressor for an air conditioner having a particularly high refrigerating capacity is driven and the impedance of the AC power supply 22 is relatively high.
[0016]
In the control device for the single-phase induction motor shown in FIG. 7, the compressor circuit depends on whether or not the voltage across the resistor Rs changes within the time limit (fixed value) after the control circuit 23 turns on the relay switch RL1a. Judging whether the start has failed. The time limit is set so that the resistance Rs can sufficiently withstand the heat generation for a short time when the compressor is started, and the compression can be started with a margin under various temperature conditions. However, since the time during which the voltage across the resistor Rs changes after the relay switch RL1a is turned on differs depending on the type of the compressor driven by the single-phase induction motor and the type of the resistor Rs, the time limit is fixed. The single-phase induction motor control device cannot be applied to various compressors.
[0017]
In view of the above problems, the present invention provides a control device for a single-phase induction motor capable of preventing a current limiting resistor from generating heat and becoming a dangerous state when a switch means for controlling energization is welded. The purpose is to provide.
[0018]
It is another object of the present invention to provide a control device for a single-phase induction motor in which the cause of the failure can be easily determined.
[0019]
Moreover, this invention provides the control apparatus of the single phase induction motor which can prevent the restart failure after an instantaneous power failure, and can prevent a large current from flowing at the time of the restart after an instantaneous power failure. Objective.
[0020]
Another object of the present invention is to provide a control device for a single-phase induction motor that can prevent erroneous detection of an instantaneous power failure.
[0021]
Another object of the present invention is to provide a control device for a single-phase induction motor that is applicable to various compressors and has excellent versatility.
[0022]
[Means for Solving the Problems]
To achieve the above object, in the control device for a single-phase induction motor according to the present invention, a single-phase induction motor having a main winding and an auxiliary winding, and power supply from an AC power source to the single-phase induction motor. A first switch means for controlling, a second switch means, a third switch means, an operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding, and the second switch means. Start that is connected in series and has a larger electrical phase shift between the main winding and the auxiliary winding when the second switch means is closed than when the second switch means is open And a capacitor for limiting current, which is connected in parallel to the third switch means and limits the current flowing to the single-phase induction motor when the third switch means is open, and from the AC power source Single phase induction A current detection means for detecting a current flowing through the machine, and whether or not the first switch means is welded based on an output signal of the current detection means, and when it is determined that the first switch means is welded Control means for bringing the third switch means into a closed state.
[0023]
With this configuration, the current limiting resistor can be short-circuited when the first switch means is welded. Therefore, when the switch means for controlling energization is welded, it is possible to prevent the current limiting resistor from generating heat and entering a dangerous state.
[0024]
Further, even if the current detection means detects a current while the single-phase induction motor is stopped, if the output signal of the current detection means is not within a predetermined range, the control means is the first switch means. You may make it not determine with having welded.
[0025]
Even if a short circuit or disconnection occurs in the current detection means, the current detection means detects the current. However, according to the above configuration, if the detected current value is not within the predetermined range, the first switch means is welded. Therefore, it can be accurately determined that the first switch means is welded.
[0026]
Moreover, a unit for determining whether the single-phase induction motor is in an overload state based on an output signal of the current detection unit may be provided.
[0027]
This makes it possible to determine whether the single-phase induction motor is in an overload state without providing new detection means. Therefore, cost reduction and size reduction can be achieved.
[0028]
In the control device for a single-phase induction motor according to the present invention, a single-phase induction motor having a main winding and an auxiliary winding, and a first switch for controlling power supply from an AC power source to the single-phase induction motor Means, second switch means, third switch means, an operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding, and connected in series to the second switch means, A starting capacitor for increasing a deviation in an electrical phase between the main winding and the auxiliary winding when the second switch means is in a closed state as compared with when the second switch means is in an open state; A current limiting resistor for limiting the current flowing through the single-phase induction motor when the third switch means is in an open state, and a pulse signal synchronized with the output voltage of the AC power supply. Generate AC power supply synchronous pulse signal generation means, first voltage detection means for detecting the voltage across the current limiting resistor, second voltage detection means for detecting the voltage across the second switch means, and the pulse A defect that identifies a cause or a malfunction location based on a signal, an output signal from the first voltage detection means, and an output signal from the second voltage detection means, and performs display according to the identified malfunction cause or malfunction location Display means.
[0029]
According to such a configuration, the cause of the failure or the location of the failure is identified, and the display according to the identified cause of the failure or the location of the failure is performed. Repairing time can be shortened.
[0030]
The first voltage detection means and the second voltage detection means may each have full-wave rectification means.
[0031]
Thereby, the speed of defect detection can be increased, and safety can be improved.
[0032]
In addition, even if a failure different from the first occurs after the failure display means first specifies the failure cause or failure location, the display corresponding to the failure cause or failure location specified first may be continued.
[0033]
Thereby, the cause investigation and repair of a malfunction can be performed accurately and in a short time.
[0034]
In the control device for a single-phase induction motor according to the present invention, a single-phase induction motor having a main winding and an auxiliary winding, and a first switch for controlling power supply from an AC power source to the single-phase induction motor Means, second switch means, third switch means, an operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding, and connected in series to the second switch means, A starting capacitor for increasing a deviation in an electrical phase between the main winding and the auxiliary winding when the second switch means is in a closed state as compared with when the second switch means is in an open state; A current limiting resistor for limiting the current flowing through the single-phase induction motor when the third switch means is in an open state, and a pulse signal synchronized with the output voltage of the AC power supply. Generate AC power supply synchronous pulse signal generating means and if the pulse signal is missing even one pulse, it is determined that there is an instantaneous power failure. If it is determined that there is an instantaneous power failure, the operation of the single-phase induction motor is stopped and a predetermined time is And a control means for controlling the first to third switch means so as to restart the single-phase induction motor after a lapse of time.
[0035]
With such a configuration, an instantaneous power failure can be reliably detected. As a result, since the instantaneous power failure cannot be detected despite the instantaneous power failure, the situation where the single-phase induction motor is restarted in the normal operation state after the recovery from the instantaneous power failure does not occur. Therefore, it is possible to prevent a restart failure after an instantaneous power failure and to prevent a large current from flowing when restarting after the instantaneous power failure.
[0036]
In the control device for a single-phase induction motor according to the present invention, a single-phase induction motor having a main winding and an auxiliary winding, and a first switch for controlling power supply from an AC power source to the single-phase induction motor Means, second switch means, third switch means, an operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding, and connected in series to the second switch means, A starting capacitor for increasing a deviation in an electrical phase between the main winding and the auxiliary winding when the second switch means is in a closed state as compared with when the second switch means is in an open state; A current limiting resistor for limiting the current flowing through the single-phase induction motor when the third switch means is in an open state, and a pulse signal synchronized with the output voltage of the AC power supply. Generate AC power supply synchronous pulse signal generation means, and when the pulse signal lacks a predetermined number of pulses during operation of the single-phase induction motor and other than when the single-phase induction motor is started, an instantaneous power failure occurs. If it is determined that there is an instantaneous power failure, the operation of the single-phase induction motor is stopped, and the first-phase third motor is restarted after a predetermined time has elapsed. Control means for controlling the switch means.
[0037]
According to such a configuration, the determination of instantaneous power failure is not performed at the start of the single-phase induction motor. It is possible to prevent erroneous detection of instantaneous power failure caused by.
[0038]
In the control device for a single-phase induction motor according to the present invention, a single-phase induction motor having a main winding and an auxiliary winding, and a first switch for controlling power supply from an AC power source to the single-phase induction motor Means, second switch means, third switch means, an operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding, and connected in series to the second switch means, A starting capacitor for increasing a deviation in an electrical phase between the main winding and the auxiliary winding when the second switch means is in a closed state as compared with when the second switch means is in an open state; A current limiting resistor that is connected in parallel to the three switch means and limits the current flowing through the single-phase induction motor when the third switch means is in an open state, and detects a voltage across the current limiting resistor. First voltage detection And if the voltage detected by the first voltage detecting means does not change within a time limit after the first switch means is closed, it is determined that the starting of the single-phase induction motor has failed. And means for changing the set value of the time limit.
[0039]
The time that the voltage detected by the first voltage detecting means changes after the first switch means is closed differs depending on the type of compressor driven by the single-phase induction motor and the type of current limiting resistor. With the above configuration, it is possible to determine the start failure of the single-phase induction motor according to the type of the compressor driven by the phase induction motor and the type of the current limiting resistor. Therefore, it can be applied to various compressors.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. Here, the case where the control device for a single-phase induction motor according to the present invention is applied to a split type air conditioner will be described. FIG. 1 shows a schematic circuit configuration of a split type air conditioner provided with a control device for a single phase induction motor according to the present invention. The split-side air conditioner in FIG. 1 includes an indoor unit 100 and an outdoor unit 101.
[0041]
First, the circuit configuration of the indoor unit 100 will be described. One output end of the power plug 5 is connected to the terminal Na, and the other output end of the power plug 5 is connected to the terminal 1a. The two output ends of the power plug 5 are connected to the control circuit 8 via the power transformer 7.
[0042]
A current transformer 6 for detecting a current flowing between the power plug 5 and the terminal Na is connected to the control circuit 8. An indoor fan motor 9 is connected to the terminal Na and the control circuit 8.
[0043]
One end of the relay switch RY1a, one end of the relay switch RY2a, and one end of the relay switch RY3a are connected in common and connected to the terminal 1a. The other end of the relay switch RY1a is connected to the terminal 2a, the other end of the relay switch RY2a is connected to the terminal 3a, and the other end of the relay switch RY3a is connected to the terminal 4a. Note that on / off control of the relay switches RY1a, RY2a, and RY3a is performed by the control circuit 8.
[0044]
Next, the circuit configuration of the outdoor unit 101 will be described. Terminal 1b is connected to one end of overcurrent relay 14 via relay switch RL1a. The other end of the overcurrent relay 14 is connected to a single-phase induction motor 15. The single-phase induction motor 15 has a main winding L1 and an auxiliary winding L2, and one end of the main winding L1 and one end of the auxiliary winding L2 are connected to the other end of the overcurrent relay 14.
[0045]
The other end of the main winding L1 is connected to one end of the operating capacitor Cr, one end of the resistor Rs, and one end of the relay switch RL4a. The other end of the auxiliary winding L2 is connected to the other end of the operating capacitor Cr and one end of the starting capacitor Cs. The other end of the starting capacitor Cs is connected to one end of the relay switch RL3a. The other end of the resistor Rs, the other end of the relay switch RL4a, and the other end of the relay switch RL3a are connected in common and connected to the terminal Nb.
[0046]
The outdoor fan motor 10 is connected to the terminals Nb and 2b, and the four-way switching valve 11 is connected to the terminals Nb and 3b. One end of the relay switch RL2a is connected to the terminal Nb via the relay coil RL1b, and the other end of the relay switch RL2a is connected to the terminal 4b. The relay coil RL1b and the relay switch RL1a form one relay. One input end of the power transformer 12 is connected to the terminal Nb, and the other input end is connected to the terminal 4b. The output side of the power transformer 12 is connected to the control circuit 13.
[0047]
The indoor unit 100 and the outdoor unit 101 are connected by connecting the terminal Na and the terminal Nb, the terminal 1a and the terminal 1b, the terminal 2a and the terminal 2b, the terminal 3a and the terminal 3b, and the terminal 4a and the terminal 4b, respectively.
[0048]
The current transformer 6 detects the total current flowing through the air conditioner in FIG. 1 and outputs the detection result to the control circuit 8. The control circuit 8 determines whether the single-phase induction motor 15 is in an overload state based on the output signal of the current transformer 6, and if it is determined that the single-phase induction motor 15 is in an overload state, the control circuit 8 sets the relay switch RY3a. Turn off and stop the air conditioner.
[0049]
FIG. 2 shows a detailed circuit configuration of a portion directly related to the control of the single-phase induction motor 15 in the outdoor unit 101. 2 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.
[0050]
The anode of the diode D4 is connected to a connection node between the operation capacitor Cr and the relay switch RL4a via the resistor R1. The anode of the diode D3 is connected to the terminal Nb via the resistor R2. The cathode of the diode D3 and the cathode of the diode D4 are connected in common, and are connected to one end of the resistor R3, one end of the capacitor C3, and the anode of the light emitting diode that is a component of the photocoupler PC1. The other end of the resistor R3, the other end of the capacitor C3, and the cathode of the light emitting diode that is a component of the photocoupler PC1 are connected to one end of the resistor R4 and one end of the resistor R5. The other end of the resistor R4 is connected to a connection node between the operation capacitor Cr and the relay switch RL4a, and the other end of the resistor R5 is connected to the terminal Nb. The collector of the phototransistor, which is a component of the photocoupler PC1, is connected to the port P3 of the microcomputer 21, one end of the resistor R11, and one end of the capacitor C5. The other end of the resistor R11 and the other end of the capacitor C5 are at ground potential. -5 [V] is applied to the emitter of the phototransistor which is a component of the photocoupler PC1.
[0051]
The circuit composed of the capacitors C3 and C5, the diodes D3 and D4, the resistors R1 to R5 and R11, and the photocoupler PC1 having such a configuration detects the voltage across the resistor Rs, and the voltage across the resistor Rs is When the voltage is zero, a detection signal is output to the port P3 of the microcomputer 21. When the voltage across the resistor Rs is not zero, the detection signal is set to a low level. Since this circuit uses a full-wave rectifier circuit composed of diodes D3 and D4, the detection speed of the voltage across the resistor Rs is fast.
[0052]
The anode of the diode D2 is connected to a connection node between the starting capacitor Cs, the relay switch RL3a, and one end of the resistor R16 via the resistor R6. The other end of the resistor R16 is connected to a connection node between the driving capacitor Cr and the starting capacitor Cs. The anode of the diode D1 is connected to the terminal Nb via the resistor R7. The cathode of the diode D1 and the cathode of the diode D2 are connected in common, and are connected to one end of the resistor R8, one end of the capacitor C2, and the anode of the light emitting diode that is a component of the photocoupler PC2. The other end of the resistor R8, the other end of the capacitor C2, and the cathode of the light emitting diode that is a component of the photocoupler PC2 are connected to one end of the resistor R9 and one end of the resistor R10. The other end of the resistor R9 is connected to a connection node between the starting capacitor Cs, the relay switch RL3a, and one end of the resistor R16, and the other end of the resistor R10 is connected to the terminal Nb. The collector of the phototransistor, which is a component of the photocoupler PC2, is connected to the port P2, the one end of the resistor R12, and the one end of the capacitor C4. The other end of the resistor R12 and the other end of the capacitor C4 are at ground potential. -5 [V] is applied to the emitter of the phototransistor which is a component of the photocoupler PC2.
[0053]
The circuit composed of the capacitors C2 and C4, the diodes D1 and D2, the resistors R6 to R10, R12, and R16, and the photocoupler PC2 configured as described above detects the voltage across the relay switch RL3a and detects the relay switch RL3a. When the voltage at both ends of the relay switch RL3a is zero, the detection signal is output to the port P2 of the microcomputer 21 when the voltage across the relay switch RL3a is not zero. Since this circuit uses a full-wave rectifier circuit composed of diodes D1 and D2, the detection speed of the voltage across the relay switch RL3a is fast.
[0054]
A fuse Fu1 is provided between the terminal 4b and the relay switch RL2a. One end of the varistor 16, one end of the capacitor C1, and one end of the primary winding of the power transformer 12 are connected to a connection point between the relay switch RL2a and the fuse Fu1. The other end of the varistor 16, the other end of the capacitor C1, and the other end of the primary winding of the power transformer 12 are connected to the terminal Nb. The secondary winding of the power transformer 12 is connected to the input side of a rectifier circuit composed of diodes D5 to D8.
[0055]
Since the output voltage of the AC power supply (not shown) is applied between the terminal Nb and the terminal 4b, the rectifier circuit composed of the diodes D5 to D8 is a full-wave voltage obtained by transforming the output voltage of the AC power supply (not shown). Rectify.
[0056]
The positive output side of the rectifier circuit composed of the diodes D5 to D8 is connected to the anode of the diode D9. The cathode of the diode D9 is connected to the input terminal of the three-terminal regulator 17 and the positive polarity side of the capacitor C6. The negative output side of the rectifier circuit including the diodes D5 to D8 is connected to the negative polarity side of the capacitor C6, the ground terminal of the three-terminal regulator 17, the negative polarity side of the capacitor C7, and one end of the resistor R13, and −12 [V] is Applied. The other end of the resistor R13 is connected to the anode of the Zener diode ZD1, the negative polarity side of the capacitor C8, and one end of the capacitor C9, and −5 [V] is applied. The output terminal of the three-terminal regulator 17 is connected to the positive side of the capacitor C7, the cathode of the Zener diode ZD1, the positive side of the capacitor C8, the other end of the capacitor C9, and the port P1 of the microcomputer 21. Note that the potential of the output terminal of the three-terminal regulator 17 becomes the ground potential.
[0057]
Accordingly, a DC voltage of the ground potential is supplied to the port P1 of the microcomputer 21. This DC voltage of the ground potential becomes the power supply voltage of the microcomputer 21.
[0058]
The positive output side of the rectifier circuit composed of the diodes D5 to D8 is also connected to one end of the resistor R15. The other end of the resistor R15 is connected to the input end of the digital transistor Q1 and one end of the capacitor C10. The output terminal of the digital transistor Q1 is connected to one end of the resistor R14, the port P10 of the microcomputer 21, and one end of the capacitor C11. −5 [V] is applied to the other end of the capacitor C10 and the other end of the capacitor C11. Further, −5 [V] is applied as a power supply voltage to the digital transistor Q1.
[0059]
The other end of the resistor R14 is connected to the anode of an LED (Light Emitting Diode) 19, the input terminal of the reset IC 18, and one end of the capacitor C12, and is at ground potential. The cathode of the LED 19 is connected to the port P11 of the microcomputer 21 via the resistor R17. The output terminal of the reset IC 18 is connected to the positive polarity side of the capacitor C13, one end of the capacitor C14, and the port P9 of the microcomputer 21. The other end of the capacitor C12, the ground terminal of the reset IC 18, the negative polarity side of the capacitor C13, and the other end of the capacitor C14 are connected in common, and −5 [V] is applied.
[0060]
The AC power supply synchronization pulse generation circuit creates an AC power supply synchronization pulse signal PUL (see FIG. 3) that is inverted at the zero crossing of an AC voltage output from an AC power supply (not shown), and the AC power supply synchronization pulse signal PUL is ported. Output to P10. Further, a reset signal is sent from the reset IC 18 to the port P9. Further, the LED 19 blinks in response to a signal output from the port P11.
[0061]
A circuit 20 composed of a crystal resonator and two capacitors is connected to ports P7 and P8 of the microcomputer 21. Then, −5 [V] is applied to the connection node of the two capacitors.
[0062]
The port P4 of the microcomputer 21 is connected to the input terminal of the digital transistor Q2. The output end of the digital transistor Q2 is connected to the cathode of the diode D10 and one end of the relay coil RL2b. The port P5 of the microcomputer 21 is connected to the input terminal of the digital transistor Q3. The output end of the digital transistor Q3 is connected to the cathode of the diode D11 and one end of the relay coil RL3b. The port P6 of the microcomputer 21 is connected to the input terminal of the digital transistor Q4. The output end of the digital transistor Q4 is connected to the cathode of the diode D12 and one end of the relay coil RL4b. The anode of the diode D10 and the other end of the relay coil RL2b are connected to one end of the temperature fuse Fu2. The anode of the diode D11, the other end of the relay coil RL3b, the anode of the diode D12, and the other end of the relay coil RL4b are connected to the other end of the temperature fuse Fu2, and −12 [V] is applied. In addition, a ground potential voltage is applied to the digital transistors Q2 to Q4 as a power supply voltage. The relay coil RL2b and the relay switch RL2a form one relay, the relay coil RL3b and the relay switch RL3a form one relay, and the relay coil RL4b and the relay switch RL4a form one relay. The temperature fuse Fu2 is installed in the vicinity of the resistor Rs, and the temperature fuse Fu2 is blown when the resistor Rs generates heat abnormally and the temperature of the resistor Rs exceeds a predetermined value.
[0063]
Next, the operation when the compressor starts normally will be described with reference to the time chart of FIG. 3 showing the states of the relay switches RL1a to RL4a when the compressor starts normally. When the power plug 5 (see FIG. 1) is connected to a commercial power outlet, an AC voltage is applied between the terminal 1b and the terminal Nb. Further, since the control circuit 8 turns on the relay switch RY3a when starting and operating the compressor, an AC voltage is also applied between the terminal Nb and the terminal 4b. As a result, the power transformer 12 is energized, a DC voltage is supplied to the port P1, and the microcomputer 21 starts operating. At the start of the operation of the microcomputer 21, the relay switches RL1a to RL4a are all off. Therefore, the relay switches RL1a to RL4a are in the period T shown in FIG. _A It becomes the state of.
[0064]
Period T _A When a high level signal is input to the port P3 of the microcomputer 21 and a high level signal is input to the port P2 of the microcomputer 21, the microcomputer 21 turns on the relay switch RL3a. Thereby, the period T _A To period T _B Migrate to
[0065]
Period T _A To period T _B When 100 [msec] has passed since the transition to, if a high level signal is input to the port P3 of the microcomputer 21 and a high level signal is input to the port P2 of the microcomputer 21, the microcomputer 21 is connected to the relay switch RL2a. Turn on. Thereby, the period T _B To period T _C Migrate to
[0066]
When the relay switch RL2a is turned on, the relay switch RL1a is also turned on. Thereby, the period T _C To period T _D Migrate to It is normal if a low level signal is input to the port P3 of the microcomputer 21 and a high level signal is input to the port P2 of the microcomputer 21 after the relay switch RL1a is turned on. If the compressor starts normally, the period T _C To period T _D The signal input to the port P3 of the microcomputer 21 changes from the low level to the high level after 0.2 seconds to 0.3 seconds have elapsed from the time of transition to the state. Period T _D Is usually 0.2 to 0.3 seconds, but if the compressor is difficult to start, wait until a maximum of 1.7 seconds have elapsed, and if the above signal condition is not met after waiting for more, start the compressor Judge as failure.
[0067]
When the signal input to the port P3 of the microcomputer 21 changes from Low level to High level, if the signal input to the port P2 of the microcomputer 21 is High level, the microcomputer 21 turns on the relay switch RL4a, and the relay switch Turn off RL3a. Thereby, the period T _D To period T _E The operation state of the compressor is switched from the start operation to the normal operation.
[0068]
Period T _E When the signal input to the port P3 of the microcomputer 21 is at a high level and the signal input to the port P2 of the microcomputer 21 is at a low level, the compressor is normally operating normally. When the compressor is normally started, the normal operation of the compressor is continued until the supply of the AC voltage from the AC power source is cut off or a stop instruction is issued.
[0069]
After the compressor has started normally, ie the period T _D To period T _E After shifting to, the microcomputer 21 determines whether or not the power supply synchronization pulse signal PUL is normally input in addition to the input signals of the ports P2 and P3.
[0070]
If the microcomputer 21 stops detecting the power supply synchronization pulse signal PUL during the normal operation of the compressor, the microcomputer 21 turns off the relay switch RL2a and the relay switch RL4a in order to stop the operation of the compressor. In the present embodiment, the control circuit 8 provided in the indoor unit 100 turns off the relay switch RY3a when detecting the operation stop operation or the thermo OFF by the user. As a result, the relay coil RL1b of the outdoor unit 101 is cut off from the supply of power, so that the relay switch RL1a is turned off before the relay switch RL2a is turned off, and the operation of the compressor is stopped. Therefore, the period T _F It becomes the state of.
[0071]
Next, the operation at the time of abnormality will be described. As is clear from FIG. 1, when the relay switch RL1a is welded, the AC power supply (not shown) → the power plug 5 → the terminal 1a → the terminal 1b → the relay switch RL1a (welded) → main while the air conditioner is stopped. Since the closed circuit of the winding L1 → resistance Rs → terminal Nb → terminal Na → power plug 5 → AC power supply (not shown) is formed, the compressor current continuously flows through the resistance Rs. In this state, the resistor Rs generates heat and becomes dangerous.
[0072]
In order to prevent such a dangerous state, the air conditioner of FIG. 2 operates as follows. When the control circuit 8 receives the detection signal output from the current transformer 6 and determines that a current is flowing through the single-phase induction motor 15 from the result of the detection signal even when the compressor is stopped, the control circuit 8 It is determined that the switch RL1a is welded, and the relay switch RY3a is turned on. As a result, the power transformer 12 is energized, and the microcomputer 21 starts operating even when the compressor is stopped. Therefore, the microcomputer 21 can perform control when an abnormality occurs.
[0073]
As a cause of the current transformer 6 detecting the current while the compressor is stopped, for example, a short circuit or disconnection of the current transformer 6 may occur in addition to the case where the relay switch RL1a is welded. Therefore, even when the current transformer 6 detects a current while the compressor is stopped, the control circuit 8 does not determine that the relay switch RL1a is welded unless the detected current value is within a predetermined range. As a result, the control circuit 8 can accurately determine that the relay switch RL1a is welded.
[0074]
Next, the operation of the microcomputer 21 will be described with reference to the flowchart of FIG. When a predetermined DC voltage is supplied to the port P1, the microcomputer 21 starts operating. Note that the variable stage is set to any one of A to G, and the time when the stage is A to D corresponds to the starting operation of the compressor. The microcomputer 21 is in an initial state at the start of operation, that is, the stage is set to A, the timer is not set, and the safety time is set to non-zero.
[0075]
First, it is determined whether the stage is A (step # 1). If the stage is A (Yes in Step # 1), the process proceeds to Step # 2. On the other hand, if the stage is not A (No in Step # 1), the safety time is set to 3 minutes and the time measurement is started (Step # 8), and then the process proceeds to Step # 21.
[0076]
In step # 2, it is determined whether it is during the safety time. If the safety time is not zero (Yes in Step # 2), the process proceeds to Step # 3. On the other hand, if the safety time is zero (No in step # 2), the process proceeds to step # 109.
[0077]
In step # 3, it is determined whether or not the input signal of the port P3 is at a high level. If the input signal of the port P3 is High level (Yes in Step # 3), the process proceeds to Step # 4. On the other hand, if the input signal of the port P3 is not High level (No in Step # 3), the process proceeds to Step # 9.
[0078]
In step # 4, it is determined whether or not the input signal of the port P2 is at a high level. If the input signal of the port P2 is High level (Yes in Step # 4), the relay switch RL3a is turned on (Step # 5), the timer is set to 0.1 second, and time measurement is started (Step # 6). ) After changing the stage to B (step # 7), the process proceeds to step # 109. On the other hand, if the input signal of the port P2 is not High level (No in Step # 4), the process proceeds to Step # 9.
[0079]
In step # 9, the microcomputer 21 determines that the problem of welding of the relay switch RL1a has occurred, and stores that the problem of welding of the relay switch RL1a has occurred. After the operation of step # 9, the microcomputer 21 turns off the relay switch RL2a (step # 10), turns off the relay switch 3a (step # 11), turns on the relay switch RL4a (step # 12), and sets the stage. After changing to G (step # 13), the process proceeds to step # 109.
[0080]
In step # 21, it is determined whether the stage is B. If the stage is B (Yes in step # 21), the process proceeds to step # 22. On the other hand, if the stage is not B (No in step # 21), the process proceeds to step # 41.
[0081]
In step # 22, it is determined whether the input signal of the port P3 is at a high level. If the input signal of the port P3 is High level (Yes in Step # 22), the process proceeds to Step # 23. On the other hand, if the input signal of the port P3 is not High level (No in Step # 22), the process proceeds to Step # 28.
[0082]
In step # 23, it is determined whether or not the input signal of the port P2 is at a high level. If the input signal of the port P2 is High level (Yes in Step # 23), the process proceeds to Step # 24. On the other hand, if the input signal of the port P3 is not High level (No in Step # 23), the process proceeds to Step # 28.
[0083]
In step # 24, it is determined whether the set time of the timer has elapsed. If the set time of the timer has elapsed (Yes in step # 24), the relay switch RL2a is turned on (step # 25), the timer is set to 0.1 second, and time measurement is started (step # 26). After changing the stage to C (step # 27), the process proceeds to step # 109. On the other hand, if the set time of the timer has not elapsed (No in step # 24), the process directly proceeds to step # 109.
[0084]
In step # 28, the microcomputer 21 determines that the failure of welding of the relay switch RL1a has occurred, and stores that the failure of welding of the relay switch RL1a has occurred. After the operation of step # 28, the microcomputer 21 turns off the relay switch RL2a (step # 29), turns off the relay switch 3a (step # 30), turns on the relay switch RL4a (step # 31), and sets the stage. After changing to G (step # 32), the process proceeds to step # 109.
[0085]
In step # 41, it is determined whether the stage is C. If the stage is C (Yes in step # 41), the process proceeds to step # 42. On the other hand, if the stage is not C (No in step # 41), the process proceeds to step # 61.
[0086]
In step # 42, it is determined whether or not the input signal of the port P2 is at a high level. If the input signal of the port P2 is High level (Yes in Step # 42), the process proceeds to Step # 43. On the other hand, if the input signal of the port P2 is not High level (No in Step # 42), the process proceeds to Step # 47.
[0087]
In step # 43, it is determined whether the set time of the timer has elapsed. If the set time of the timer has not elapsed (No in step # 43), the process proceeds to step # 44. On the other hand, if the set time of the timer has elapsed (Yes in step # 43), the process proceeds to step # 48.
[0088]
In step # 44, it is determined whether or not the input signal of the port P3 is at a low level. If the input signal of the port P3 is Low level (Yes in Step # 44), the timer is set to 1.7 seconds to start measuring time (Step # 45), and the stage is changed to D (Step # 46). Thereafter, the process proceeds to step # 109. Note that the set time of the timer in step # 45 can be changed by an external signal S1 (see FIG. 3) input to the port P12. This makes it possible to set the set time of the timer in step # 45 according to the type of compressor to be driven and the type of resistor Rs. Since the set time of the timer in step # 45 is a time limit used when determining whether or not the start of the compressor has failed, various changes can be made by changing the set time of the timer in step # 45. It can be applied to a compressor. On the other hand, if the input signal of the port P3 is not Low level (No in Step # 44), the process directly proceeds to Step # 109.
[0089]
In step # 47, the microcomputer 21 determines that the malfunction that the relay switch RL3a does not operate has occurred, and stores that the malfunction that the relay switch RL3a does not operate has occurred.
[0090]
In step # 48, the microcomputer 21 determines that the malfunction that the relay switch RL1a does not operate has occurred, and stores that the malfunction that the relay switch RL1a does not operate has occurred.
[0091]
After the operation of step # 47 or step # 48, the microcomputer 21 turns off the relay switch RL2a (step # 49), turns off the relay switch 3a (step # 50), and changes the stage to A (step #). 51) to Step # 109.
[0092]
In step # 61, it is determined whether or not the stage is D. If the stage is D (Yes in step # 61), the process proceeds to step # 62. On the other hand, if the stage is not D (No in step # 61), the process proceeds to step # 81.
[0093]
In step # 62, it is determined whether or not the input signal of the port P2 is at a high level. If the input signal of the port P2 is High level (Yes in Step # 62), the process proceeds to Step # 63. On the other hand, if the input signal of the port P2 is not High level (No in Step # 62), the process proceeds to Step # 69.
[0094]
In step # 63, it is determined whether the timer set time has elapsed. If the set time of the timer has not elapsed (No in step # 63), the process proceeds to step # 64. On the other hand, if the set time of the timer has elapsed (Yes in step # 63), the process proceeds to step # 70.
[0095]
In step # 64, it is determined whether the input signal of the port P3 is at a high level. If the input signal of the port P3 is High level (Yes in Step # 64), the relay switch RL3a is turned off (Step # 65), the relay switch RL4a is turned on (Step # 66), and the timer is set to 0.1 second. The time is set to start (step # 67), the stage is changed to E (step # 68), and then the process proceeds to step # 109. On the other hand, if the input signal of the port P3 is not High level (No in Step # 64), the process directly proceeds to Step # 109.
[0096]
In step # 69, the microcomputer 21 determines that the malfunction that the relay switch RL3a does not operate has occurred, and stores that the malfunction that the relay switch RL3a does not operate.
[0097]
In step # 70, the microcomputer 21 determines that the problem of failure in starting the compressor has occurred, and stores that the problem of failure in starting the compressor has occurred.
[0098]
After the operation of Step # 69 or Step # 70, the microcomputer 21 turns off the relay switch RL2a (Step # 71), turns off the relay switch 3a (Step # 72), and changes the stage to A (Step # 71). 73) to Step # 109.
[0099]
In step # 81, it is determined whether or not the stage is E. If the stage is E (Yes in step # 81), the process proceeds to step # 82. On the other hand, if the stage is not E (No in step # 81), the process proceeds to step # 101.
[0100]
In step # 82, it is determined whether or not the input signal of the port P3 is at a high level. If the input signal of the port P3 is High level (Yes in Step # 82), the process proceeds to Step # 83. On the other hand, if the input signal of the port P3 is not High level (No in Step # 82), the process proceeds to Step # 86.
[0101]
In step # 83, it is determined whether the timer set time has elapsed. If the set time of the timer has elapsed (Yes in step # 83), the process proceeds to step # 84. On the other hand, if the set time of the timer has not elapsed (No in step # 83), the process proceeds to step # 109.
[0102]
In step # 84, it is determined whether the power supply synchronization pulse signal PUL has a missing pulse. If there is no missing pulse in the power supply synchronization pulse signal PUL (Yes in step # 84), the process proceeds to step # 85. On the other hand, if there is even one missing pulse in the power supply synchronization pulse signal PUL (No in step # 84), the process proceeds to step # 87.
[0103]
In step # 85, it is determined whether or not the input signal of the port P2 is at a low level. If the input signal of the port P2 is Low level (Yes in Step # 85), the process proceeds to Step # 109. On the other hand, if the input signal of the port P2 is not Low level (No in Step # 85), the process proceeds to Step # 88.
[0104]
In step # 86, the microcomputer 21 determines that the malfunction that the relay switch RL4a does not operate has occurred, and stores that the malfunction that the relay switch RL4a does not operate.
[0105]
In step # 87, the microcomputer 21 determines that a problem of instantaneous power failure has occurred, and stores that a problem of instantaneous power failure has occurred.
[0106]
In step # 88, the microcomputer 21 determines that a problem of operation of the overcurrent relay (OCR) 14 has occurred, and stores that a problem of operation of the overcurrent relay (OCR) 14 has occurred.
[0107]
After the operation of step # 86, # 87, or # 88, the microcomputer 21 turns off the relay switch RL2a (step # 89), sets the timer to 0.01 seconds, and starts measuring time (step # 90). Then, the stage is changed to F (step # 91) and the process proceeds to step # 109.
[0108]
In step # 101, it is determined whether the stage is F. If the stage is F (Yes in step # 101), the process proceeds to step # 102. On the other hand, if the stage is not F (No in step # 101), that is, if the stage is G, the relay switch RL2a is turned off (step # 105), the relay switch RL3a is turned off (step # 106), and the relay switch The RL 4a is turned on (step # 107), the stage remains G (step # 108), and the process proceeds to step # 109.
[0109]
In step # 102, it is determined whether the set time of the timer has elapsed. If the set time of the timer has elapsed (Yes in Step # 102), the relay switch RL4a is turned off (Step # 103), the stage is changed to A (Step # 104), and the process proceeds to Step # 109. On the other hand, if the set time of the timer has not elapsed (No in step # 102), the process directly proceeds to step # 109.
[0110]
In step # 109, the microcomputer 21 generates a control signal according to the type of the stored failure, and causes the LED 19 to blink by outputting the control signal from the port P11. The blinking pattern of the LED 19 is as shown in FIG. When normal, the LED 19 blinks at a cycle of 1 second. On the other hand, when an abnormality occurs, the LED 19 blinks in a pattern in which three blinks of a 0.2 second cycle are inserted a number of times corresponding to the type of the defect between blinks of a 1 second cycle. For example, the blinking state of the LED 19 when the compressor fails to start is as shown in FIG.
[0111]
As shown in FIG. 5, since seven types of defects are displayed by blinking of the LED 19, the defective part can be repaired in a short time during production or service.
[0112]
The microcomputer 21 first identifies the cause of the failure or the location of the failure, and causes the LED 19 to display according to the identified failure. If the failure is minor, the gas pressure balance of the refrigeration cycle is stable. The compressor is restarted after a suitable time has elapsed. Even if this restart is performed normally, the microcomputer 21 continues to display the LED 19 according to the first identified failure. As a result, even when a problem occurs occasionally or when the reproducibility of the problem is poor, the cause of the problem can be easily determined.
[0113]
Furthermore, even if a problem different from the problem first identified when restarting occurs, the microcomputer 21 continues to display the LED 19 according to the problem identified first. Thereby, the cause investigation and repair of a malfunction can be performed accurately and in a short time. For example, when the failure that the relay switch RL4a does not operate first occurs, the temperature fuse Fu2 is secondarily cut. Thereafter, when the compressor is restarted, the microcomputer 21 determines that a failure has occurred in which the relay switch RL1a does not operate due to the blowout of the thermal fuse Fu2. Here, if the microcomputer 21 causes the LED 19 to display according to the malfunction of the temperature fuse Fu2, the temperature fuse Fu2 is first replaced when repairing, but the relay switch RL4a is not repaired, so the temperature fuse Fu2 again. Will be cut. Therefore, as in the present embodiment, it is desirable that the microcomputer 21 operates so as to continuously display the LED 19 according to the first identified defect.
[0114]
After performing the operation of step # 109, the process proceeds to step # 1.
[0115]
When the microcomputer 21 determines that the relay switch RL1a is welded, the microcomputer 21 turns on the relay switch RL4a (step # 12 or # 31) to short-circuit the resistor Rs. Therefore, when the relay switch RL1a is welded, the resistor Rs is reduced. It is possible to prevent a dangerous state due to heat generation.
[0116]
In step # 84 and # 87, the microcomputer 21 determines that the AC power supply synchronization pulse signal PUL is missing even at one pulse, it is an instantaneous power failure, stops the compressor, and balances the gas pressure in the refrigeration cycle. The compressor is restarted after a time suitable for stabilization (timer set time in step # 90) has elapsed. As a result, it is possible to prevent a failure in restarting the compressor caused by restarting the compressor in a normal operation state because no instantaneous power failure is detected when a short instantaneous power failure occurs, and a large current is supplied to the single-phase induction motor 15. Can be prevented from flowing.
[0117]
Further, the microcomputer 21 determines whether or not the AC power supply synchronization pulse signal PUL has a missing pulse when the stage is E, but the AC power supply when the corresponding stage is A to D during the starting operation of the compressor. Because it does not determine whether the synchronization pulse signal PUL has a missing pulse, it is caused by a decrease in the output voltage of the AC power supply caused by a large current flowing at the start of the single-phase induction motor that drives the compressor, or a disturbance in the output voltage waveform of the AC power supply It is possible to prevent erroneous detection of instantaneous power failure.
[0118]
In the present embodiment, the control device for a single-phase induction motor according to the present invention is applied to a split-type air conditioner. However, the control device can also be applied to a window air conditioner or other electric device including a single-phase induction motor.
[0119]
【The invention's effect】
According to the present invention, it is possible to realize a control device for a single-phase induction motor that can prevent a current limiting resistor from generating heat and becoming a dangerous state when a switch means for controlling energization is welded.
[0120]
In addition, according to the present invention, it is possible to realize a control device for a single-phase induction motor that makes it easy to investigate the cause of a failure.
[0121]
Further, according to the present invention, it is possible to realize a control device for a single-phase induction motor that can prevent a restart failure or a large current after an instantaneous power failure.
[0122]
Moreover, according to the present invention, it is possible to realize a control device for a single-phase induction motor capable of preventing erroneous detection of an instantaneous power failure.
[0123]
Moreover, according to the present invention, it is possible to realize a control device for a single-phase induction motor that is applicable to various compressors and has excellent versatility.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic circuit configuration of a split type air conditioner provided with a control device for a single-phase induction motor according to the present invention.
FIG. 2 is a diagram showing a circuit configuration relating to a portion directly related to control of a single-phase induction motor in the outdoor unit included in the air conditioner of FIG.
FIG. 3 is a time chart showing the state of a relay switch when the compressor is normally started.
4 is a flowchart showing an operation of a microcomputer provided in an outdoor unit included in the air conditioner of FIG.
5 is a diagram showing a blinking pattern of LEDs provided in an outdoor unit included in the air conditioner of FIG. 1. FIG.
6 is a diagram showing an example of a blinking pattern of LEDs provided in an outdoor unit included in the air conditioner of FIG. 1. FIG.
FIG. 7 is a diagram showing a schematic circuit configuration example of a conventional control device for a single-phase induction motor.
[Explanation of symbols]
6 Current transformer
8, 13 Control circuit
15 Single-phase induction motor
19 LED
21 Microcomputer
C1-C14 capacitors
Cr operation capacitor
Cs capacitor for starting
D1-D12 diode
L1 main winding
L2 Auxiliary winding
R1-R17 resistance
RL1a to RL4a Relay switch
RL1b to RL4b Relay coil
Rs Current limiting resistor
S1 External signal

Claims (9)

A single-phase induction motor having a main winding and an auxiliary winding;
First switch means for controlling power supply from an AC power source to the single-phase induction motor;
A second switch means;
A third switch means;
An operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding;
It is connected in series to the second switch means, and when the second switch means is in the closed state, the electric power between the main winding and the auxiliary winding is greater than when the second switch means is in the open state. A starting capacitor to increase the phase shift;
A current limiting resistor connected in parallel to the third switch means and limiting a current flowing through the single-phase induction motor when the third switch means is in an open state;
In a control device for a single-phase induction motor equipped with
Current detection means for detecting a current flowing from the AC power source to the single-phase induction motor;
Based on the output signal of the current detection means, it is determined whether the first switch means is welded, and when it is determined that the first switch means is welded, the third switch means is closed. Control means;
A control device for a single-phase induction motor. Even if the current detection means detects a current while the single-phase induction motor is stopped, if the output signal of the current detection means is not within a predetermined range, the control means welds the first switch means. The control device for a single-phase induction motor according to claim 1, which is not determined as follows. The control device for a single-phase induction motor according to claim 1 or 2, further comprising means for determining whether the single-phase induction motor is in an overload state based on an output signal of the current detection means. A single-phase induction motor having a main winding and an auxiliary winding;
First switch means for controlling power supply from an AC power source to the single-phase induction motor;
A second switch means;
A third switch means;
An operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding;
It is connected in series to the second switch means, and when the second switch means is in the closed state, the electric power between the main winding and the auxiliary winding is greater than when the second switch means is in the open state. A starting capacitor to increase the phase shift;
A current limiting resistor connected in parallel to the third switch means and limiting a current flowing through the single-phase induction motor when the third switch means is in an open state;
In a control device for a single-phase induction motor equipped with
AC power supply synchronization pulse signal generating means for generating a pulse signal synchronized with the output voltage of the AC power supply,
First voltage detecting means for detecting a voltage across the current limiting resistor;
Second voltage detecting means for detecting a voltage across the second switch means;
Based on the pulse signal, the output signal of the first voltage detection means, and the output signal of the second voltage detection means, the cause of the failure or the failure location is specified, and a display corresponding to the specified failure cause or failure location is displayed. Malfunction display means to perform,
A control device for a single-phase induction motor. 5. The control device for a single-phase induction motor according to claim 4, wherein each of the first voltage detection means and the second voltage detection means has full-wave rectification means. 5. The display according to claim 4 or claim 4, wherein, even if a defect different from the first occurs after the defect display means first identifies the defect cause or defect location, the display according to the first identified failure cause or defect location is continued. The control device for a single-phase induction motor according to claim 5. A single-phase induction motor having a main winding and an auxiliary winding;
First switch means for controlling power supply from an AC power source to the single-phase induction motor;
A second switch means;
A third switch means;
An operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding;
It is connected in series to the second switch means, and when the second switch means is in the closed state, the electric power between the main winding and the auxiliary winding is greater than when the second switch means is in the open state. A starting capacitor to increase the phase shift;
A current limiting resistor connected in parallel to the third switch means and limiting a current flowing through the single-phase induction motor when the third switch means is in an open state;
In a control device for a single-phase induction motor equipped with
AC power supply synchronization pulse signal generating means for generating a pulse signal synchronized with the output voltage of the AC power supply,
If even one pulse is missing, it is determined that there is an instantaneous power failure. If it is determined that there is an instantaneous power failure, the operation of the single-phase induction motor is stopped, and the single-phase induction motor is turned off after a predetermined time has elapsed. Control means for controlling the first to third switch means to restart,
A control device for a single-phase induction motor. A single-phase induction motor having a main winding and an auxiliary winding;
First switch means for controlling power supply from an AC power source to the single-phase induction motor;
A second switch means;
A third switch means;
An operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding;
It is connected in series to the second switch means, and when the second switch means is in the closed state, the electric power between the main winding and the auxiliary winding is greater than when the second switch means is in the open state. A starting capacitor to increase the phase shift;
A current limiting resistor connected in parallel to the third switch means and limiting a current flowing through the single-phase induction motor when the third switch means is in an open state;
In a control device for a single-phase induction motor equipped with
AC power supply synchronization pulse signal generating means for generating a pulse signal synchronized with the output voltage of the AC power supply,
If the pulse signal lacks a predetermined number of pulses during a period other than when the single-phase induction motor is operating and during the operation of the single-phase induction motor, it is determined that there is an instantaneous power failure, Control means for controlling the first to third switch means to stop the operation of the single-phase induction motor when it is determined and restart the single-phase induction motor after a predetermined time has elapsed;
A control device for a single-phase induction motor. A single-phase induction motor having a main winding and an auxiliary winding;
First switch means for controlling power supply from an AC power source to the single-phase induction motor;
A second switch means;
A third switch means;
An operating capacitor for shifting the electrical phase of the main winding and the auxiliary winding;
It is connected in series to the second switch means, and when the second switch means is in the closed state, the electric power between the main winding and the auxiliary winding is greater than when the second switch means is in the open state. A starting capacitor to increase the phase shift;
A current limiting resistor connected in parallel to the third switch means and limiting a current flowing through the single-phase induction motor when the third switch means is in an open state;
In a control device for a single-phase induction motor equipped with
First voltage detecting means for detecting a voltage across the current limiting resistor;
Means for determining that the start of the single-phase induction motor has failed if the voltage detected by the first voltage detection means does not change within a time limit after the first switch means is closed;
Means for changing a set value of the time limit;
A control device for a single-phase induction motor.

Images