JP2005341750A - Motor starting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save energy by achieving no power consumption by a starting device used for staring the motor of an electric compressor. <P>SOLUTION: A positive temperature coefficient thermistor 7 and a contact 102 are connected in series to an auxiliary winding 3 of the motor 1. By closing the contact 102 by using a pulse voltage at a starting time and by opening and closing the contact with less electric power both at the starting time and after starting, the auxiliary windings are electrically separated from a power source. As a result, the motor starting device consumes almost no electric power so that the motor starting device of high-energy efficiency can be provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor starting device for an electric compressor mounted on an electric refrigerator, an air conditioner or the like.

  2. Description of the Related Art Conventionally, devices using a positive temperature coefficient thermistor have been widely used as motor starting devices for electric compressors. However, in recent years, it has been desired that energy efficiency is high considering the global environment, and attention is paid to the fact that the power supply voltage continues to be applied to the positive temperature coefficient thermistor even after the motor is started, and the motor is started. After that, there is one that cuts off the power supply voltage applied to the positive temperature coefficient thermistor (see, for example, Patent Document 1).

  Hereinafter, the conventional motor starting device will be described with reference to the drawings.

  FIG. 4 is a circuit diagram of a conventional motor starting device described in Patent Document 1. In FIG.

  In FIG. 4, a main winding 2 and an auxiliary winding 3 of a motor 1 constituting an electric compressor (not shown) are provided, and are connected to an AC power source 4 via a switch 5. The starting device 6 is a positive temperature coefficient thermistor 7 connected in series to the auxiliary winding 3 of the motor 1, a thermostat 8 which is connected in series to the positive temperature coefficient thermistor 7 and opens and closes due to the influence of heat, and a positive characteristic. The heating element 9 is a positive temperature coefficient thermistor that is connected in parallel to the thermistor 7 and the thermostat 8 and has a thermal effect on the thermostat 8.

  The positive temperature coefficient thermistor 7 is made of, for example, an oxide semiconductor ceramic containing barium titanate as a main component, has a Curie temperature, and has a characteristic that an electric resistance value rapidly increases when the Curie temperature is exceeded.

  The operation of the motor starting device configured as described above will be described below.

  For example, when the inside of the refrigerator is lowered to a set temperature, the switch 5 is in an open state, and the electric compressor is stopped.

  However, for example, when the refrigerator internal temperature rises and the electric compressor is operated, the switch 5 is closed, electricity is supplied from the AC power supply 4, and a starting current flows through the main winding 2. Then, a starting current flows through the auxiliary winding 3 through the thermostat 8 and the positive characteristic thermistor 7, and a current determined by the resistance value of the heating element 9 also flows through the heating element 9.

  Since the temperature of the heating element 9 is low at the start-up, the thermostat 8 is closed, and the positive temperature coefficient thermistor 7 is also in a low electric resistance value. Starts driving.

  After the motor 1 is started, the positive temperature coefficient thermistor 7 self-heats above the Curie temperature in a few seconds, so that the electrical resistance value increases rapidly and the current of the auxiliary winding 3 decreases, so that the auxiliary winding 3 is substantially disconnected. It is. Normally, the positive temperature coefficient thermistor 7 continues to maintain the self-heating necessary for maintaining a high electrical resistance value, and thus continues to consume several watts of power during the operation of the motor 1.

Further, since the power supply voltage is also applied to the heating element 9 connected in parallel with the positive temperature coefficient thermistor 7, the heating element 9 self-heats, and the thermostat 8 senses the self-heating of the heating element 9 and reaches a set temperature. Turn off. When the thermostat 8 is turned off, the application of the power supply voltage to the positive temperature coefficient thermistor 7 is cut off, and no power is consumed in the positive temperature coefficient thermistor 7, thereby saving energy.
JP-A-6-38467

  However, in the above conventional configuration, the power consumption of the positive temperature coefficient thermistor 7 is eliminated and the power consumption is reduced as a whole. However, during operation of the motor 1, the heating element 9 is energized due to self-heating, and the power is consumed. Had a problem of consumption.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a motor starter with high energy efficiency that eliminates most of the power consumption of the motor starter during motor operation.

  In order to solve the above problems, a motor starting device of the present invention includes a motor having a main winding and an auxiliary winding, a first coil that opens a contact when energized, and a second that closes a contact when energized. The power is consumed by the motor starter by energizing the first coil and closing the contact when the compressor is started by the control circuit, and energizing the second coil and opening the contact after the start. Can be reduced.

  The motor starter of the present invention starts the motor by closing the contact with a small amount of electric power at the time of start-up, and electrically disconnects the auxiliary winding via the contact with a small amount of power after the start-up. It is possible to provide a motor starter with almost no energy efficiency.

  The invention according to claim 1 includes a positive temperature coefficient thermistor and a contact arranged in series with the auxiliary winding, a first coil that opens the contact when energized, and a second coil that closes the contact when energized And a control circuit having a first energizing means for energizing the first coil with a pulse voltage and a second energizing means for energizing the second coil with a pulse voltage, and the first coil and the first coil The contact is opened and closed by energizing the second coil, and the auxiliary winding is electrically disconnected from the power supply after the motor is started. A small amount of power is required to open and close the contact of the motor starting device. However, electric power for continuing the open state and the closed state of the contact is not necessary, and a motor starter with high energy efficiency can be provided.

  According to a second aspect of the present invention, there is provided a control circuit according to the first aspect, further comprising timer means for measuring a time after the motor is started and outputting a signal to the second energizing means after a predetermined time of the start. The energizing means 2 energizes the second coil by the output of the timer means, and the time for closing the contact can be arbitrarily set, and the auxiliary winding can be electrically disconnected by the timer. In addition to the effects of the described invention, it is possible to reliably start the motor with the simple function of the timer and to reliably disconnect the auxiliary winding from the power source.

  According to a third aspect of the present invention, the control circuit includes: a current detection unit that detects a current of the positive temperature coefficient thermistor; and a current determination unit that determines a current value detected by the current detection unit and outputs a result. The energizing means energizes the second coil by the output of the current determining means, and detects that the positive temperature coefficient thermistor has become high resistance by the current of the positive temperature coefficient thermistor and opens the contact. In addition to the effects of the described invention, the contact can be reliably opened after the resistance becomes high regardless of variations in the resistance change time of the positive temperature coefficient thermistor, and the start-up can be ensured.

According to a fourth aspect of the present invention, the control circuit includes a voltage detection unit that detects the voltage of the positive temperature coefficient thermistor, and a voltage determination unit that determines a voltage value detected by the voltage detection unit and outputs the result. The energizing means energizes the second coil by the output of the voltage determining means, and detects that the positive temperature coefficient thermistor becomes high resistance due to a change in voltage across the positive temperature coefficient thermistor. In addition to the effect of the invention, the contact can be reliably opened after the resistance becomes high, regardless of variations in the resistance change time of the positive temperature coefficient thermistor, and the start-up can be ensured. Furthermore, it can be realized at low cost.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

  Further, the same components as those of the conventional example are denoted by the same reference numerals, and detailed description thereof is omitted.

(Embodiment 1)
FIG. 1 is a circuit diagram of a motor starting device according to Embodiment 1 of the present invention.

  Hereinafter, the present embodiment will be described with reference to FIG.

  In FIG. 1, a starting device 101 includes a positive temperature coefficient thermistor 7, a contact 102, a first coil 104 that opens the contact 102 with a pulse voltage, and a second coil that closes the contact 102 with a pulse voltage. 105.

  The control circuit 106 includes a timer unit 107, a first energizing unit 108, and a second energizing unit 109. The first energization means 108 outputs a voltage pulse to the first coil 104 when the switch 5 is closed.

  The timer means 107 starts a timer operation when the motor 1 is started after the switch 5 is closed, measures the time after the motor 1 is started, and sends a signal to the second energizing means 109 when the preset time is reached. The second energizing means 109 receives the output of the timer means 107 and outputs a voltage pulse to the second coil 105.

  The operation and action of the motor starting device configured as described above will be described below.

  For example, when the internal temperature of the refrigerator rises and the electric compressor is operated, the switch 5 is closed, electricity is supplied from the AC power supply 4, and a starting current flows through the main winding 2. Further, the closing of the switch 5 is detected, and the first energizing means 108 outputs a voltage pulse to the first coil 104, whereby the contact 102 is closed, and the starting current is passed through the auxiliary winding 3 through the positive temperature coefficient thermistor 7 and the contact 102. Flows and the motor 1 starts. At this time, only the pulse of the first energizing means 108 is required to close the contact 102.

  The timer means 107 detects the closing of the switch 5 and starts a timer operation. Then, when a preset time is reached, a signal is output to the second energizing means 109, and the second energizing means 109 outputs a voltage pulse to the second coil 105 to open the contact 102. Then, the current flowing through the positive temperature coefficient thermistor 7 is cut off to complete the start-up.

  Since only the pulse of the second energizing means 109 may be used as the power for opening the contact 102, almost no power is consumed, and no power is consumed to maintain the contact 102 open. .

  Therefore, after the start-up is completed, the supply of the power supply voltage to the positive temperature coefficient thermistor 7 is cut off, and the power of the circuit that cuts off the supply of the power supply voltage to the positive temperature coefficient thermistor 7 is not required, so that the energy saving of the starter can be achieved. Moreover, it can be configured with a simple configuration with a timer function.

  In addition, the timer means can arbitrarily set the time after starting to output a signal to the second energizing means, so higher energy saving is realized by setting the optimal time according to the motor and the starting device can do.

(Embodiment 2)
FIG. 2 is a circuit diagram of the motor starting device according to Embodiment 2 of the present invention.

  Note that the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  Hereinafter, the present embodiment will be described with reference to FIG.

  In FIG. 2, the starting device 110 includes a positive temperature coefficient thermistor 7, a contact 102, a current detection unit 112, a first coil 104 that opens the contact 102 with a pulse voltage, and a contact that is closed with the pulse voltage. A second coil 105 is provided. The current detection means 112 detects the current flowing through the positive temperature coefficient thermistor 7 and outputs an output proportional to the flowing current to the current determination means 114.

  The control circuit 113 includes a current determination unit 114, a first energization unit 108, and a second energization unit 109. The current determination unit 114 detects the output of the current detection unit 112, and outputs a signal to the second energization unit 109 when the current is less than a preset value. The second energization unit 109 applies a voltage to the second coil 105. Output a pulse.

  Further, the first energization means 108 outputs a voltage pulse to the first coil 104 when the switch 5 is closed.

  The operation and action of the motor starting device configured as described above will be described below.

  If the internal temperature of the refrigerator rises and is closed when the electric compressor is operated, the switch 5 is closed, electricity is supplied from the AC power supply 4, and a starting current flows through the main winding 2. Further, the closing of the switch 5 is detected, and the first energizing means 108 outputs a voltage pulse to the first coil 104, whereby the contact 102 is closed, and the starting current is passed through the auxiliary winding 3 through the positive temperature coefficient thermistor 7 and the contact 102. Flows and the motor 1 starts. At this time, only the pulse of the first energizing means 108 is required to close the contact 102.

  When the motor 1 is started, a large current flows because the resistance value of the positive temperature coefficient thermistor 7 is low. The current detection means 112 detects the current flowing through the positive characteristic thermistor 7 and sends an output proportional to the current to the current determination means 114. The current determination means 114 has a preset output value of the current detection means 112. If it becomes below, a signal will be output to the 2nd electricity supply means 109. FIG.

  Therefore, since the current flowing through the positive temperature coefficient thermistor 7 is large, the current determination means 114 does not output a signal to the second energization means 109, the contact 102 is not opened and the closed state is maintained, and the current flows through the positive temperature coefficient thermistor 7. to continue.

  Thereafter, the positive temperature coefficient thermistor 7 self-heats above the Curie temperature in a few seconds, the electric resistance value increases rapidly, and the current of the auxiliary winding 3 decreases after the motor 1 is started.

  The current detection means 112 outputs a value corresponding to the current to the current determination means 114, the current determination means 114 determines that the current has decreased, outputs a signal to the second energization means 109, and the second The energization means 109 outputs a voltage pulse to the second coil 105 to open the contact 102. When the contact 102 is in an open state, the current flowing through the positive temperature coefficient thermistor 7 is cut off and the start-up is completed.

  Since only the pulse of the second energizing means 109 may be used as the power for opening the contact 102, almost no power is consumed, and no power is consumed to maintain the contact 102 open. .

  Therefore, after the start-up is completed, the supply of the power supply voltage to the positive temperature coefficient thermistor 7 is cut off, and the power of the circuit for cutting off the supply of the power supply voltage to the positive temperature coefficient thermistor 7 is no longer necessary, thereby eliminating the power consumption of the starter. Energy saving can be achieved.

  Further, when electricity is supplied from the AC power supply 4, the positive temperature coefficient thermistor 7 rises in temperature and changes its resistance value. However, there is a variation in the resistance value over time, and the resistance value increases substantially. Although the time when the auxiliary winding 3 is disconnected varies, in the present embodiment, by detecting the current, the contact 102 is surely opened regardless of the variation with time of the resistance of the positive temperature coefficient thermistor 7. And start-up can be completed reliably.

  In the embodiment of the present invention, the current detection unit and the current determination unit are provided. However, the current detection unit and the current determination unit are the same unit, and the current flowing through the positive temperature coefficient thermistor is detected and the current value is detected. If it has a function of judging the above and outputting the result, it can be implemented similarly.

(Embodiment 3)
FIG. 3 is a circuit diagram of a motor starting device according to Embodiment 3 of the present invention.

  The same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  Hereinafter, the present embodiment will be described with reference to FIG.

  In FIG. 3, the starting device 120 includes a positive temperature coefficient thermistor 7, a contact 102, a first coil 104 that opens the contact 102 with a pulse voltage, and a second coil 105 that closes the contact with a pulse voltage. doing.

  The control circuit 121 includes voltage detection means 123, voltage determination means 122, first energization means 108, and second energization means 109. The voltage determination means 122 determines the voltage value detected by the voltage detection means for detecting the voltage across the positive characteristic thermistor 7, and outputs a signal to the second energization means 109 if the voltage value exceeds a preset value. The second energization means 109 outputs a voltage pulse to the second coil 105.

  Further, the first energization means 108 outputs a voltage pulse to the first coil 104 when the switch 5 is closed.

  About operation | movement of the motor starting apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  If the internal temperature of the refrigerator rises and is closed when the electric compressor is operated, the switch 5 is closed, electricity is supplied from the AC power supply 4, and a starting current flows through the main winding 2. Further, the closing of the switch 5 is detected, and the first energizing means 108 outputs a voltage pulse to the first coil 104, whereby the contact 102 is closed, and the starting current is passed through the auxiliary winding 3 through the positive temperature coefficient thermistor 7 and the contact 102. Flows and the motor 1 starts. At this time, only the pulse of the first energizing means 108 is required to close the contact 102.

  Since the resistance value of the positive temperature coefficient thermistor 7 is low when the motor 1 is started, the voltage at both ends is small. Here, the voltage determination unit 122 determines the voltage value of the voltage detection unit 123 that detects the voltage across the positive characteristic thermistor 7 and outputs a signal to the second energization unit 109 if the voltage value exceeds a preset value. Since the voltage at both ends is low, no signal is output to the second energizing means 109, the contact 102 is not opened and the closed state is maintained, and the current continues to flow through the positive temperature coefficient thermistor 7.

  Thereafter, the positive temperature coefficient thermistor 7 self-heats above the Curie temperature within a few seconds, the electric resistance value increases rapidly, and after the motor 1 starts, the voltage across the positive temperature coefficient thermistor 7 of the auxiliary winding 3 rises.

  Then, the voltage determination means 122 determines that the voltage at both ends has increased, outputs a signal to the second energization means 109, and the second energization means 109 outputs a voltage pulse to the second coil 105. The contact 102 is opened. When the contact 102 is in an open state, the current flowing through the positive temperature coefficient thermistor 7 is cut off and the start-up is completed.

  Since only the pulse of the second energizing means 109 may be used as the power for opening the contact 102, almost no power is consumed, and no power is consumed to maintain the contact 102 open. .

  Therefore, after the start-up is completed, the supply of the power supply voltage to the positive temperature coefficient thermistor 7 is cut off, and the power of the circuit for cutting off the supply of the power supply voltage to the positive temperature coefficient thermistor 7 is not required, so that the power consumption of the starter is eliminated. Energy saving can be achieved.

  Further, when electricity is supplied from the AC power supply 4, the positive temperature coefficient thermistor 7 rises in temperature and changes its resistance value. However, there is a variation in the resistance value over time, and the resistance value increases substantially. Although the time when the auxiliary winding 3 is disconnected varies, in the present embodiment, by detecting the voltage, the contact 102 is surely opened regardless of the variation with time of the resistance of the positive temperature coefficient thermistor 7. And start-up can be completed reliably.

  Moreover, since it has a simple configuration for detecting the voltage across the positive temperature coefficient thermistor 7, it can be realized at low cost.

  In the embodiment of the present invention, the voltage detection means and the voltage determination means are provided. However, the voltage detection means and the voltage determination means are the same one means, and the voltage across the positive characteristic thermistor is detected and its voltage value is detected. If it has a function of judging the above and outputting the result, it can be implemented similarly.

  As described above, since the motor starter according to the present invention can save energy, it can be applied to refrigeration cycles such as a dehumidifier, a showcase, and a vending machine in addition to an electric refrigerator and an air conditioner.

Circuit diagram of motor starter according to Embodiment 1 of the present invention Circuit diagram of motor starter according to Embodiment 2 of the present invention Circuit diagram of motor starter according to Embodiment 3 of the present invention Circuit diagram of conventional motor starter

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Main winding 3 Auxiliary winding 7 Positive characteristic thermistor 102 Contact 104 1st coil 105 2nd coil 106,113,121 Control circuit 107 Timer means 108 1st electricity supply means 109 2nd electricity supply means 112 Current Detection means 114 Current determination means 122 Voltage determination means 123 Voltage detection means

Claims (4)

  A motor having a main winding and an auxiliary winding, a positive temperature coefficient thermistor and a contact arranged in series with the auxiliary winding, a first coil that opens the contact when energized, and a contact that is closed when energized A control circuit having a second coil, a first energizing means for energizing the first coil with a pulse voltage, and a second energizing means for energizing the second coil with a pulse voltage; A motor starter characterized in that the contact is opened and closed by energizing the coil and the second coil, and the auxiliary winding is electrically disconnected from the power supply after the motor is started.   The control circuit includes a timer unit that measures a time after the start of the motor and outputs a signal to the second energization unit after a predetermined time of the start, and the second energization unit is configured to output a second signal by the output of the timer unit. The motor starting device according to claim 1, wherein the coil is energized.   The control circuit includes a current detection unit that detects a current of the positive temperature coefficient thermistor, and a current determination unit that determines a current value detected by the current detection unit and outputs a result, and the second energization unit includes the current The motor starting device according to claim 1, wherein the second coil is energized by the output of the determining means.   The control circuit includes voltage detection means for detecting the voltage of the positive temperature coefficient thermistor, and voltage determination means for determining the voltage value detected by the voltage detection means and outputting the result, and the second energization means includes the voltage The motor starting device according to claim 1, wherein the second coil is energized by the output of the determining means.

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