Direct current motor starting device

Abstract

The utility model discloses a DC motor starting device, which comprises a power supply, a PLC controller, a starting resistor, a DC motor and a contactor, the DC motor comprises a first DC motor and a second DC motor, the output end of the power supply is divided into two paths, one path is electrically connected with the PLC controller, and the other path is divided into two branches, wherein one branch is electrically connected with a first direct-current motor with higher power after a starting resistor is connected in series in an armature loop, the other branch is directly and electrically connected with a second direct-current motor with lower power, the direct-current motors are electrically connected with the PLC through a contactor, and a starting interlocking circuit of the two direct-current motors is arranged in a control circuit of the PLC. According to the utility model, the PLC is adopted to control the starting circuit of the direct current motor, the resistor is connected in series in the armature loop of the motor, and the PLC is utilized to control the time for cutting off the resistor, thereby effectively solving the problems of serious heating of the high-power direct current motor, large impact on a power supply, influence on other equipment in the same power supply line and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic circuits, and in particular relates to a DC motor starting device. Background Art

[0002] DC motors are widely used in various fields such as railway transportation, industrial production, agricultural automation, shipping, aerospace and household appliances. DC motors have the advantages of good mechanical characteristics, convenient speed control and stable and reliable operation. Compared with other types of motors, DC motors have greater overload capacity, large thermal and braking torque, can achieve smooth stepless speed regulation, and a wide speed regulation range. Therefore, DC motors are often used in occasions with high requirements for starting and speed regulation.

[0003] When a DC motor is started at full voltage, the starting impact current can be up to ten to twenty times the rated current, which will damage the motor and the equipment being driven. Excessive starting current will cause the motor to heat up severely, and will also damage the motor armature winding. It will also cause the grid voltage to drop instantly, affecting the normal operation of other nearby electrical equipment. Especially for large and medium capacity motors, the starting current is even greater, and the starting torque is also very large. Excessive torque will damage the transmission mechanism of the driving system and affect the service life of the equipment. Excessive current causes a great impact on the power supply, greatly shortening its service life. Therefore, control equipment must be used to limit the starting current; in addition, if the capacity of the power transformer is not large enough, direct starting will cause the output voltage of the power transformer to drop significantly, which will not only reduce the starting torque of the motor itself, but also affect the normal operation of other equipment in the same power supply line. Utility Model Content

[0004] The purpose of the utility model is to provide a DC motor starting device, aiming to solve the problems existing in the prior art in the above-mentioned background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A DC motor starting device comprises a power supply, a PLC controller, a starting resistor, a DC motor and a contactor, wherein the DC motor comprises a first DC motor and a second DC motor, wherein the output end of the power supply is divided into two paths, one path is electrically connected to the PLC controller, and the other path is divided into two branches, wherein one branch is electrically connected to the first DC motor after being connected in series with a starting resistor in an armature circuit, and the other branch is directly electrically connected to the second DC motor, wherein the power of the first DC motor is greater than that of the second DC motor, the first DC motor and the second DC motor are electrically connected to the PLC controller respectively through a contactor, and a starting interlocking circuit for the first DC motor and the second DC motor is provided in a control circuit of the PLC controller.

[0007] Preferably, the output end of the power supply is also provided with an extension terminal, the PLC controller is electrically connected to a timer and / or a counter and / or a timer through a relay, and the timer, the counter, and the timer are electrically connected to the extension terminal. Further, the relay adopts a Siemens 3RH2122-2KF40 contactor relay.

[0008] Preferably, the power supply adopts a MZMW S-5000-110 switching power supply with an input of AC220V, an output of DC110V, and a maximum output current of 45A.

[0009] Preferably, the PLC controller adopts Siemens s7-200PLC CPU222 programmable logic controller.

[0010] Preferably, the contactor is ABB AF09-30-10-13 contactor.

[0011] Preferably, the starting resistor is a 200W 2Ω gold aluminum shell resistor.

[0012] Compared with the shortcomings and deficiencies of the prior art, the utility model has the following beneficial effects:

[0013] The utility model adopts a PLC controller to control the starting circuit of the DC motor, and can accurately and efficiently control the start and stop time, running time, emergency stop of the DC motor, etc.; by connecting a resistor in series with the motor armature circuit and using the PLC to control the time of cutting off the resistor, the starting current of the motor is limited to make it smoother, thereby achieving the purpose of protecting the motor. It better solves the problems of serious heating of high-power DC motors, large impact on power supply, and affecting other equipment in the same power supply line, and realizes stable starting and smooth speed regulation of the starting circuit, prolongs the service life of the DC motor, reduces the operating steps of the operator, and strengthens the power use specifications and operation safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of a DC motor starting device provided by an embodiment of the utility model.

[0015] Figure 2 The utility model provides an electrical control principle diagram of a DC motor starting device.

[0016] In the figure: 1. power supply, 2. PLC controller, 3. starting resistor, 4. first DC motor, 5. second DC motor, 6. contactor, 7. air switch, 8. relay, 9. external motor terminal, 10. extension terminal, 11. start button, 12. fixing plate. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0018] Reference Figure 1-2 A DC motor starting device includes a power supply 1, a PLC controller 2, a starting resistor 3, a first DC motor 4, a second DC motor 5 and a contactor 6, wherein the power supply 1, the PLC controller 2, the starting resistor 3 and the contactor 6 are installed on a fixed plate 12, and the output end of the power supply 1 is divided into two paths, one of which is electrically connected to the PLC controller 2, and the other is divided into two branches, one of which is electrically connected to the first DC motor 4 with a larger power (within 2.2kW) after the starting resistor 3 is connected in series in the armature circuit, and the starting is completed by connecting the starting resistor 3 in series in the armature circuit; the other branch is directly electrically connected to the second DC motor 5 with a smaller power. The first DC motor 4 and the second DC motor 5 are electrically connected to the PLC controller 2 through the contactor 6 respectively, and the control circuit of the PLC controller 2 is provided with a starting interlock circuit of the first DC motor 4 and the second DC motor 5. Since the starting interlock of the two motors is set in the PLC, only one DC motor can be operated at a time through the control of the PLC controller 2, and a starting button 11 for controlling the starting of the first DC motor 4 and the second DC motor 5 is provided on the PLC controller 2, Figure 2 The start button 11 of the first DC motor 4 is SB1, and the start button 11 of the second DC motor 5 is SB2.

[0019] The power supply 1 adopts MZMW S-5000-110 switching power supply, with an input of AC220V, an output of DC110V, and a maximum output current of 45A; the PLC controller 2 adopts Siemens s7-200PLC CPU222 programmable logic controller, which can meet more complex control requirements, is easy to operate, simple to use, and has a rich instruction set; the contactor 6 adopts ABB AF09-30-10-13 contactor, and the starting resistor 3 adopts a 200W 2Ω gold aluminum shell resistor. Figure 2 A, B, C, D, E, and F are external motor connection terminals 9, and B and E are not used in practice.

[0020] The output end of the power supply 1 is also provided with an expansion terminal 10 ( Figure 2 In FIG. 1 , the PLC controller 2 is electrically connected to a timer and / or a counter and / or a timer through a relay 8. The timer, the counter and the timer are electrically connected to the extension terminal 10. The relay 8 adopts a Siemens 3RH2122-2KF40 contactor relay.

[0021] Reference Figure 2 , Principle of DC motor starting device:

[0022] 220V AC power is input to the input end of the switching power supply UR through a 63A air switch 7, and a DC voltage of 110V is output at the output end, with a maximum output current of 45A. One circuit supplies power to the PLC controller 2, and the other circuit supplies power to the DC motor that needs to be started.

[0023] The starting process of the first DC motor 4: When the start button SB1 of the first DC motor 4 is pressed, the I0.0 input of the PLC controller 2 is 24V, and the Q0.0 output is high potential (110V). The coil of the KM1 contactor 6 is energized, the KM1 contactor 6 is energized, the main contact KM1-1 is connected, point A is connected to the motor excitation winding, and point C is connected to the armature circuit winding in series with the starting resistor 3. The motor is started in stages, the KM3 contactor 6 is energized, and the KM3-1 main contact is energized to short-circuit the resistor R1. Then, the KM4 contactor 6 is energized, and the KM4-1 main contact is energized to short-circuit the resistor R2. The current limiting resistor is cut off, and the first DC motor 4 enters normal operation. When the start button SB1 is pressed again, the I0.0 input is disconnected, Q0.1 outputs a low potential, the KM1 contactor 6 coil loses power, the main contact is disconnected, the first DC motor 4 stops, and at the same time, Q0.2 and Q0.3 of the PLC controller 2 output a low potential, causing the KM3 contactor 6 and KM4 contactor 6 coils to lose power, the main contact is released, and the current limiting resistor is added to the circuit to prepare for the next start.

[0024] The starting process of the second DC motor 5: when the start button SB2 of the second DC motor 5 is pressed, the I0.1 input of the PLC controller 2 is 24V, and the Q0.1 outputs a high potential (110V), the KM2 contactor 6 coil is energized, the KM2 contactor 6 is energized, the main contact KM2-1 is connected, the motor's excitation winding is connected at point D, and the motor's armature circuit winding is connected at point F, and the second DC motor 5 works. When the start button SB2 is pressed again, the I0.1 input is disconnected, the Q0.1 outputs a low potential, the KM2 contactor 6 coil is de-energized, the main contact is disconnected, and the second DC motor 5 stops.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A DC motor starting device, characterized in that: It includes a power supply, a PLC controller, a starting resistor, a DC motor and a contactor. The DC motor includes a first DC motor and a second DC motor. The output end of the power supply is divided into two paths, one of which is electrically connected to the PLC controller, and the other is divided into two branches. One branch is electrically connected to the first DC motor after being connected in series with a starting resistor in an armature circuit, and the other branch is directly electrically connected to the second DC motor. The power of the first DC motor is greater than that of the second DC motor. The first DC motor and the second DC motor are electrically connected to the PLC controller respectively through a contactor. A starting interlocking circuit for the first DC motor and the second DC motor is provided in the control circuit of the PLC controller.

2. The DC motor starting device according to claim 1, characterized in that: The output end of the power supply is also provided with an extension terminal, and the PLC controller is electrically connected to a timer and / or a counter and / or a timer through a relay, and the timer, the counter, and the timer are electrically connected to the extension terminal.

3. The DC motor starting device according to claim 2, characterized in that: The relay is a Siemens 3RH2122-2KF40 contactor relay.

4. The DC motor starting device according to claim 1 or 2, characterized in that: The power supply adopts a MZMW S-5000-110 switching power supply with an input of AC220V, an output of DC110V, and a maximum output current of 45A.

5. The DC motor starting device according to claim 1, characterized in that: The PLC controller adopts Siemens s7-200PLC CPU222 programmable logic controller.

6. The DC motor starting device according to claim 1, characterized in that: The contactor is ABB AF09-30-10-13 contactor.

7. The DC motor starting device according to claim 1, characterized in that: The starting resistor is a 200W 2Ω gold aluminum shell resistor.

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