Low-power-consumption motor starter
By using a combination of current transformer, thyristor, and positive temperature coefficient thermistor in the motor starter, the problem of high power consumption of motor starter in the prior art is solved, and the motor starting effect with low power consumption and high reliability is achieved.
Patent Information
- Application Number
- CN202420655633.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-01
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-04-01
AI Technical Summary
In the prior art, the motor starter has a problem of high power consumption, especially after the start is completed, the current still passes, resulting in waste of electricity.
A low-power motor starter is adopted, including a current transformer, a thyristor and a positive temperature coefficient thermistor. The current transformer samples the current signal of the main winding circuit, triggers the on-off conversion of the thyristor, and effectively shuts down the heating power consumption generated by starting the PTC chip.
The ultra-low power consumption of the motor starter is achieved, close to the "zero power consumption" starter, which improves energy saving efficiency, and improves the reliability and safety of the equipment by simplifying circuit layout and reducing the number of components.
Smart Images
Figure CN222620915U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a low-power motor starter, which is mainly used for starting a refrigerator compressor motor and can also be used for starting other single-phase asynchronous motors. Background Art
[0002] At present, the fixed-frequency refrigeration compressors used in refrigerators generally use single-phase asynchronous motors. Single-phase asynchronous motors are usually composed of a rotor and a stator, and the stator is composed of a main winding and a secondary winding. In addition to starting the motor, the secondary winding can also participate in auxiliary operation when the motor is running normally to improve the operating efficiency of the motor. Therefore, the complete secondary winding circuit can usually be represented by a parallel secondary winding operation circuit and a secondary winding starting circuit. When the motor is powered on, the main winding and the secondary winding are energized at the same time. The current flowing through the winding generates an alternating rotating magnetic field on the stator, causing the rotor to start rotating, and gradually increases in speed as the rotor torque increases. Generally, when the speed reaches more than 75%-80% of the rated speed, the secondary winding starting circuit should be cut off in time. At this time, the motor can continue to increase in speed until the rated speed and enter the normal operating state. The connection and disconnection of the secondary winding are completed by the starter.
[0003] The starters currently used include PTC starters, electronic starters, and current induction starters.
[0004] The PTC starter uses the R / T characteristics of the PTC thermistor to achieve starting. When the motor starts, the PTC has a low resistance at room temperature, and the current flowing through the secondary winding is large, causing the PTC to heat up and the resistance to rise rapidly. When the temperature reaches the Curie point, the resistance can reach more than several thousand ohms, reducing the current in the secondary winding circuit to about ten milliamperes, basically cutting off the secondary winding. After starting, in order to maintain the heating of the PTC element and maintain a high resistance state, a maintenance current of more than ten milliamperes still flows through the PTC element. This maintenance current will generate a power consumption of about 3W, resulting in a large waste of electrical energy. In order to reduce this power consumption, the current measure is to add a bidirectional thyristor and a trigger PTC that controls the on and off of the bidirectional thyristor on the basis of the PTC starter. Its working principle is to use the trigger current of the series circuit of the trigger junction of the trigger PTC and the bidirectional thyristor to control the main switch of the bidirectional thyristor to delay the shutdown of the starting PTC circuit, thereby eliminating the power consumption of about 3W generated by the starting PTC. However, the trigger PTC needs to maintain the small current of the trigger circuit of the bidirectional thyristor, which will still generate a power consumption of about 0.5W.
[0005] The working principle of the electronic starter is to use an electronic circuit to control the on and off of the starting circuit switch. The electronic starters currently used generally have complex circuit designs and more electronic components, resulting in higher manufacturing costs and increased reliability risks. At the same time, there is also a certain amount of power consumption, so they are not widely used in the market.
[0006] The working principle of the current induction starter is to control the on and off of the switch in series on the secondary winding by sampling the current change of the main winding of the motor and using the principle of current induction. At the beginning of starting, the starting current of the main winding is large, and the starting circuit switch is controlled to be turned on; after the motor is started, the main winding current drops, and the starting circuit switch is controlled to be turned off to complete the entire starting process. The starting circuit switch uses mechanical contacts for the heavy hammer starter. The starting circuit switch uses an electronic switch for the induction type contactless starter, and the bidirectional thyristor is generally used more. The contactless starter can effectively improve the problems of short life and explosion-proof caused by the ignition of mechanical contacts. However, the induction type contactless starter in the prior art still has the problem of unreasonable device layout. Summary of the invention
[0007] The technical problem solved by the present application is to overcome the above-mentioned deficiencies in the prior art and to provide a current induction type low-power consumption motor starter with a more reasonable structural design.
[0008] The technical solution adopted by the present application to solve the above technical problems is: a low-power motor starter, including a current transformer, a bidirectional thyristor, a positive temperature coefficient thermistor, a first connecting terminal, a second connecting terminal, and a third connecting terminal. The main winding of the motor is connected in series to the two ends of the AC power supply through the first connecting terminal, the primary coil of the current transformer, and the third connecting terminal. The second pole of the bidirectional thyristor is connected to the third connecting terminal. It is characterized in that: the motor auxiliary winding is connected in series with the second connecting terminal, the positive temperature coefficient thermistor, and the bidirectional thyristor to form a switching motor auxiliary winding loop, and the secondary coil of the current transformer is connected between the trigger pole of the bidirectional thyristor and the positive temperature coefficient thermistor; when the main winding of the motor is started, the bidirectional thyristor is turned on to assist the motor to start, and when the motor enters a normal operating state, the bidirectional thyristor is turned off, so that the power consumption generated by the low-power motor starter reaches an ultra-low power consumption of milliwatts, which is close to a "zero power" starter.
[0009] The first connection method of the present application is: one end of the positive temperature coefficient thermistor is connected to the secondary winding end of the motor through the second connecting terminal; the second pin of the secondary coil of the current transformer is respectively connected to the other end of the positive temperature coefficient thermistor and the first pole of the bidirectional thyristor.
[0010] The second connection method of the present application is: one end of the positive temperature coefficient thermistor is connected to the second pin of the secondary coil of the current transformer and then connected to the secondary winding end of the motor through the second connecting terminal; the other end of the positive temperature coefficient thermistor is connected to the first pole of the bidirectional thyristor.
[0011] The low-power motor starter comprises a first connection terminal, a second connection terminal, a third connection terminal, a spring sheet, a connector, a bidirectional thyristor, a current transformer, and a positive temperature coefficient thermistor. The first connection terminal is provided with a first connection terminal welding end, a first connection terminal jack end, and a first connection terminal plug end. The second connection terminal is provided with a second connection terminal spring end, a second connection terminal jack end, and a second connection terminal plug end. The third connection terminal is provided with a third connection terminal welding end 1, a third connection terminal welding end 2, and a third connection terminal plug end. The spring sheet is provided with a spring sheet spring end and a spring sheet welding end, the connector is provided with a connector welding end, the bidirectional thyristor is provided with a first pole, a second pole and a trigger pole, and the current transformer is provided with a primary coil first pin, a primary coil second pin, a secondary coil first pin and a secondary coil second pin; the overall layout is arranged in four rows from front to back, the first row is configured with a first connection terminal body and a second connection terminal, the second row is configured with a positive temperature coefficient thermistor, the third row is configured with a spring sheet spring end, the fourth row is configured with a bidirectional thyristor, a connector, a current transformer and a first connection terminal welding end, a spring sheet welding port and a third connection terminal, and the bidirectional thyristor is installed in the front and back directions to reduce the influence of the positive temperature coefficient thermistor heating on the bidirectional thyristor, The positive temperature coefficient thermistor is relatively located in the middle to reduce the possibility of accidental damage; the first connection terminal and the third connection terminal body are located on the same side, and the first connection terminal welding end is connected to the first pin of the primary coil of the current transformer; the second connection terminal spring end is connected to one side of the positive temperature coefficient thermistor, and the other side of the positive temperature coefficient thermistor is connected to the spring end of the spring sheet, and the spring sheet welding end is connected to the first pin of the secondary coil of the current transformer and the first pole of the bidirectional thyristor; the third connection terminal welding end one is connected to the second pin of the primary coil of the current transformer CT, and the third connection terminal welding end two is connected to the second pole of the bidirectional thyristor; the bidirectional thyristor trigger pole is connected to the second pin of the secondary coil of the current transformer through the connector welding end.
[0012] Compared with the prior art, this application has the following advantages:
[0013] After the layout of the circuit design product is optimized, the distance between the lead pins of each connection end is larger, and there is a better electrical clearance. When assembling the first, second, and third connection terminals, the base is first installed in the direction of the plug end, which has better guidance, positioning and processability. When the user assembles, the mutual inductor and thyristor can be more stably positioned without shifting the position. Therefore, the production glue filling process is removed. Since the PTC chip is directly connected in series with the motor auxiliary winding, it will be placed in the center of the product during the design layout to better prevent damage and breakage of the PTC chip during falling or transportation collision.
[0014] The present application uses a current transformer to sample the current signal of the main winding loop and triggers the on-off conversion of the bidirectional thyristor, which can effectively shut down the heat power consumption generated by the starting PTC chip. The power consumption of the current sampling system can be as low as milliwatts when the motor is operating normally, close to "zero power consumption", thereby greatly improving energy saving efficiency. In addition, the number of components is small, the circuit layout is reasonable, safe and reliable, which ensures the motor starting function and improves the reliability of the motor starting performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is the electrical schematic diagram of Example 1 of the present application.
[0016] Figure 2 This is the electrical schematic diagram of Example 2 of the present application.
[0017] Figure 3 It is a schematic diagram of the three-dimensional structure of an embodiment of the present application.
[0018] Figure 4 It is a schematic diagram of the connection structure of the embodiment of the present application after the outer shell is removed.
[0019] In the figure: a first pin 1 of a primary coil, a second pin 2 of a primary coil, a first pin 3 of a secondary coil, a second pin 4 of a secondary coil, a first connecting terminal 5, a first connecting terminal welding end 51, a first connecting terminal socket end 52, a first connecting terminal plug end 53, a second connecting terminal 6, a second connecting terminal spring end 61, a second connecting terminal socket end 62, a second connecting terminal plug end 63, a third connecting terminal 7, a third connecting terminal welding end 1 71, a third connecting terminal welding end 2 72, a third connecting terminal plug end 73, a spring sheet 8, a spring sheet spring end 81, a spring sheet welding port 82, a connector 9, a connector welding end 91, a bidirectional thyristor T, a first pole A1, a second pole A2, a trigger pole G, a positive temperature coefficient thermistor PTC, a current transformer CT, and a housing 10. DETAILED DESCRIPTION
[0020] The present application will be further described in detail below in conjunction with the accompanying drawings and through examples. The following examples are intended to explain the present application but the present application is not limited to the following examples. Figure 4 The left side in the middle is the front and the right side is the back.
[0021] See also Figure 1 to Figure 4The low-power motor starter of the embodiment of the present application includes a current transformer CT, a bidirectional thyristor T, and a positive temperature coefficient thermistor PTC; the low-power motor starter can start the motor MY after being connected to the motor MY and the AC power supply. The motor auxiliary winding of the present application is connected in series with the second connection terminal 6, the positive temperature coefficient thermistor PTC, and the bidirectional thyristor T to form a switch-type motor auxiliary winding loop, and the secondary coil of the current transformer CT is connected between the trigger pole G of the bidirectional thyristor T and the positive temperature coefficient thermistor PTC; when the main winding of the motor is started, the bidirectional thyristor T is turned on to assist the motor MY in starting, and when the motor MY enters the normal operating state, the bidirectional thyristor T is turned off, so that the power consumption generated by the low-power motor starter reaches ultra-low power consumption of milliwatt level, which is close to a "zero power consumption" starter.
[0022] The low-power motor starter of the present application includes a first connecting terminal 5, a second connecting terminal 6, a third connecting terminal 7, a spring sheet 8, a connector 9, a bidirectional thyristor T, a current transformer CT, and a positive temperature coefficient thermistor PTC. The first connecting terminal 5 is provided with a first connecting terminal welding end 51, a first connecting terminal jack end 52, and a first connecting terminal plug end 53. The second connecting terminal 6 is provided with a second connecting terminal spring end 61, a second connecting terminal jack end 62, and a second connecting terminal plug end 63. The third connecting terminal 7 is provided with a third connecting terminal welding end 1 71, a third connecting terminal welding end 2 72, and a third connecting terminal plug end 73. The spring sheet 8 is provided with a spring sheet spring end 81 and a spring sheet welding end 82. The connector 9 is provided with a connector welding end 91. The bidirectional thyristor T is provided with a first pole A1, a second pole A2 and a trigger pole G. The current transformer CT is provided with a primary coil first pin 1, a primary coil second pin 2, a secondary coil first pin 3, and a secondary coil second pin 4. The overall layout of the electrical components of the present application is as follows: four rows are arranged in sequence from front to back, the first row is configured with the first connection terminal 5 body (including the first connection terminal jack end 52, the first connection terminal plug end 53), the second connection terminal 6, the second row is configured with the positive temperature coefficient thermistor PTC, the third row is configured with the spring leaf spring end 81, the fourth row is configured with the bidirectional thyristor T, the connector 9, the current transformer CT and the first connection terminal welding end 51, the spring leaf welding port 82, and the third connection terminal 7; the bidirectional thyristor T is installed in the front and back directions to reduce the influence of the positive temperature coefficient thermistor PTC heating on the bidirectional thyristor T, and the positive temperature coefficient thermistor PTC is relatively located in the middle to reduce the possibility of accidental damage; the first connection terminal 5 and the third connection terminal 7 body (including the third connection terminal welding end) are connected to the main body of the first connection terminal 5 and the third connection terminal 7. The first connection terminal welding end 51 is connected to the first pin 1 of the primary coil of the current transformer CT; the second connection terminal spring end 61 is connected to one side of the positive temperature coefficient thermistor PTC, and the other side of the positive temperature coefficient thermistor PTC is connected to the spring end 81 of the spring sheet, and the spring sheet welding end 82 is connected to the first pin 3 of the secondary coil of the current transformer CT and the first pole A1 of the bidirectional thyristor T; the third connection terminal welding end 71 and the third connection terminal welding end 72 are respectively connected to the second pin 2 of the primary coil of the current transformer CT and the second pole A2 of the bidirectional thyristor T; the trigger pole G of the bidirectional thyristor T is connected to the second pin 4 of the secondary coil of the current transformer CT through the connector welding end 91.
[0023] Example 1
[0024] The low power consumption motor starter in this embodiment adopts Figure 1The first technical solution shown in FIG. 1 includes a current transformer CT, a bidirectional thyristor T, and a positive temperature coefficient thermistor PTC. The overall structure is as follows: Figure 3 As shown, a first connecting terminal 5, a second connecting terminal 6, and a third connecting terminal 7 are provided. The first connecting terminal 5 and the second connecting terminal 6 are respectively connected to the two ends of the motor MY, and the third connecting terminal 7 is connected to the N end of the AC power supply. The primary coil 1 end of the current transformer CT is connected to the main winding end M of the motor MY through the first connecting terminal 5; one end of the positive temperature coefficient thermistor PTC is connected to the secondary winding end S of the motor MY through the second connecting terminal 6; the primary coil 2 end of the current transformer CT is connected to the second pole A2 of the bidirectional thyristor T and then connected to the N end of the AC power supply through the third connecting terminal 7; the secondary coil 3 end of the current transformer CT is respectively connected to the other end of the positive temperature coefficient thermistor PTC and the first pole A1 of the bidirectional thyristor T, the secondary coil 4 end of the current transformer CT is connected to the trigger pole G of the bidirectional thyristor T, and the C end of the motor MY is connected to the L end of the AC power supply. From the above connection, it can be seen that the main winding of the motor MY and the primary coil of the current transformer CT are connected in series to form the main winding running circuit, the secondary coil of the current transformer CT and the G-A1 junction of the bidirectional thyristor T are connected in series to form the bidirectional thyristor trigger circuit, and the secondary winding of the motor MY, the positive temperature coefficient thermistor PTC and the main switch A1-A2 of the bidirectional thyristor T are connected in series to form the secondary winding starting circuit. After the AC power supply L and N terminals are energized, since the motor is in a stalled state at the beginning of power-on, a large current will pass through its main winding circuit, causing a large current to flow through the primary coil of the current transformer CT. Under the action of electromagnetic induction, the secondary coil of the current transformer CT will induce a current of a corresponding proportion. Under the premise that the current transformer CT selects appropriate parameters, the induced current of the secondary coil is sufficient to trigger the main switch A1-A2 of the bidirectional thyristor T to turn on, the secondary winding starting circuit is connected to generate a starting current, and the motor starts to run. The positive temperature coefficient thermistor PTC connected in series in the starting circuit is in the starting current. Under the action of the current transformer CT, the induced current of the secondary coil is also much smaller than the initial power-on period. Under the premise of selecting appropriate parameters for the current transformer CT, the induced current will not trigger the main switch A1-A2 of the bidirectional thyristor T to turn on, and the auxiliary winding starting circuit will be completely shut down. At this time, the power consumption generated by the current transformer CT sampling system can reach ultra-low power consumption at the milliwatt level, which is similar to a "zero power" starter.
[0025] Example 2
[0026] The low power consumption motor starter in this embodiment adopts Figure 2The second technical solution shown in the figure has been appropriately improved on the basis of the first technical solution in terms of its connection mode. The difference is that one end of the positive temperature coefficient thermistor PTC is connected to the secondary coil 3 end of the current transformer CT and then connected to the secondary winding end S of the motor MY through the second connection terminal 6; the other end of the positive temperature coefficient thermistor PTC is connected to the first pole A1 of the bidirectional thyristor T. In this solution, the secondary coil of the current transformer CT, the positive temperature coefficient thermistor PTC and the G-A1 junction of the bidirectional thyristor T are connected in series to form a trigger circuit. The appropriate parameters of the current transformer CT are selected so that when the motor starts, the induced current of the secondary coil of the current transformer CT is sufficient to trigger the main switch A1-A2 of the bidirectional thyristor T to connect the secondary winding starting circuit. When the motor starts and is in normal operation after completion, the induced current of the secondary coil of the current transformer CT will not trigger the main switch A1-A2 of the bidirectional thyristor T to connect the secondary winding starting circuit.
Claims
1. A low-power motor starter, comprising a current transformer, a bidirectional thyristor, a positive temperature coefficient thermistor, a first connection terminal, a second connection terminal, and a third connection terminal, wherein the motor main winding is connected in series to the two ends of an AC power supply through the first connection terminal, the primary coil of the current transformer, and the third connection terminal, and the second pole of the bidirectional thyristor is connected to the third connection terminal, characterized in that: The motor auxiliary winding is connected in series with the second connecting terminal, the positive temperature coefficient thermistor, and the bidirectional thyristor to form a switching motor auxiliary winding loop, and the secondary coil of the current transformer is connected between the bidirectional thyristor trigger pole and the positive temperature coefficient thermistor; when the motor main winding is started, the bidirectional thyristor is turned on to assist the motor to start, and when the motor enters the normal operating state, the bidirectional thyristor is turned off.
2. The low power consumption motor starter according to claim 1, characterized in that: One end of the positive temperature coefficient thermistor is connected to the secondary winding end of the motor through a second connecting terminal; the second pin of the secondary coil of the current transformer is respectively connected to the other end of the positive temperature coefficient thermistor and the first pole of the bidirectional thyristor.
3. The low power consumption motor starter according to claim 1, characterized in that: One end of the positive temperature coefficient thermistor is connected to the second pin of the secondary coil of the current transformer and then connected to the secondary winding end of the motor through the second connecting terminal; the other end of the positive temperature coefficient thermistor is connected to the first pole of the bidirectional thyristor.
4. The low power consumption motor starter according to claim 1, characterized in that: The low-power motor starter comprises a first connection terminal, a second connection terminal, a third connection terminal, a spring sheet, a connector, a bidirectional thyristor, a current transformer, and a positive temperature coefficient thermistor. The first connection terminal is provided with a first connection terminal welding end, a first connection terminal jack end, and a first connection terminal plug end. The second connection terminal is provided with a second connection terminal spring end, a second connection terminal jack end, and a second connection terminal plug end. The third connection terminal is provided with a third connection terminal welding end 1, a third connection terminal welding end 2, and a third connection terminal plug end. The spring sheet is provided with a spring sheet spring end and a spring sheet welding end, the connector is provided with a connector welding end, the bidirectional thyristor is provided with a first pole, a second pole and a trigger pole, and the current transformer is provided with a primary coil first pin, a primary coil second pin, a secondary coil first pin and a secondary coil second pin; the overall layout is arranged in four rows from front to back, the first row is configured with a first connection terminal body and a second connection terminal, the second row is configured with a positive temperature coefficient thermistor, the third row is configured with a spring sheet spring end, the fourth row is configured with a bidirectional thyristor, a connector, a current transformer and a first connection terminal welding end, a spring sheet welding port and a third connection terminal, and the bidirectional thyristor is installed in the front and back directions to reduce the influence of the positive temperature coefficient thermistor heating on the bidirectional thyristor, The positive temperature coefficient thermistor is relatively located in the middle to reduce the possibility of accidental damage; the first connection terminal and the third connection terminal body are located on the same side, and the first connection terminal welding end is connected to the first pin of the primary coil of the current transformer; the second connection terminal spring end is connected to one side of the positive temperature coefficient thermistor, and the other side of the positive temperature coefficient thermistor is connected to the spring end of the spring sheet, and the spring sheet welding end is connected to the first pin of the secondary coil of the current transformer and the first pole of the bidirectional thyristor; the third connection terminal welding end one is connected to the second pin of the primary coil of the current transformer CT, and the third connection terminal welding end two is connected to the second pole of the bidirectional thyristor; the bidirectional thyristor trigger pole is connected to the second pin of the secondary coil of the current transformer through the connector welding end.