Forward and reverse rotation direct current motor and fly-wheel diode protection circuit

Abstract

The utility model discloses a forward and reverse direct current motor and fly-wheel diode protection circuit, which comprises a direct current motor M, and a fly-wheel diode D1 and a fly-wheel diode D2 which are connected with the positive electrode and the negative electrode of the direct current motor M. A contactor KM1 is switched on, a contactor KM2 is switched off, the direct current motor M rotates forward, and at the moment of power failure, current maintains that a direct current voltage positive electrode M1 flows to a direct current voltage negative electrode M2; the reverse potential is completely limited by the normally-closed contact KM2, the fly-wheel diode D1 and the return direct-current voltage positive electrode M1, the contactor KM2 is switched on, the contactor KM1 is switched off, and the direct-current motor M rotates reversely, at the moment of power failure, the direct-current voltage negative electrode M2 is maintained to flow towards the direct-current voltage positive electrode M1 by current, and the reverse potential is completely limited by the normally-closed contact KM1, the fly-wheel diode D2 and the return direct-current voltage negative electrode M2. Therefore, the direct-current motor M is protected, the motor is prevented from being damaged by overhigh voltage pulse generated by reverse induced potential at the switching moment of the direct-current motor M, and the service life of the direct-current motor is further prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of DC motor operation, and in particular relates to a forward and reverse DC motor and freewheeling diode protection circuit. Background Art

[0002] The forward and reverse control circuit of the DC motor is not only widely used in the control circuit of the power test equipment, but also widely used in some industrial automation equipment to adjust the voltage rise and fall and the reactor air gap by the forward and reverse rotation of the motor. In order to control the reverse potential, a varistor is connected to the motor in the conventional way. When controlling the forward and reverse rotation of the DC motor, reverse induced potential and overvoltage will appear at the moment of switching of the DC motor, which may easily generate excessively high voltage pulses that will damage the motor and cause other faults, and thus fail to play the role of protection in the switching of the DC motor. Utility Model Content

[0003] The utility model aims to provide a forward and reverse DC motor and a freewheeling diode protection circuit to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a forward and reverse DC motor and freewheeling diode protection circuit, comprising a DC motor M, and a freewheeling diode D1 and a freewheeling diode D2 connected to the positive and negative poles of the DC motor M, the negative poles of the freewheeling diode D1 and the freewheeling diode D2 are connected to a normally closed contact KM1 and a normally closed contact KM2, and the DC voltage positive pole M1 end and the DC voltage negative pole M2 end of the DC motor M are connected to contactors KM1 and KM2 for limiting the reverse potential of the DC motor M in forward and reverse rotation.

[0005] Preferably, one end of the contactor KM1 is connected to one end of the contactor KM2, wherein one end of the contactor KM1 and the contactor KM2 are connected to the normally closed contact KM1 and the normally closed contact KM2, and the normally closed contact KM1 and the normally closed contact KM2 can be used to limit the reverse current during the switching process of the DC motor.

[0006] Preferably, the cathode of the freewheeling diode D1 is connected to one end of the DC voltage positive electrode M1 of the DC motor M, the cathode of the freewheeling diode D2 is connected to one end of the DC voltage negative electrode M2 ​​of the DC motor M, and the anode of the freewheeling diode D1 is connected to the anode of the freewheeling diode D2, so as to protect the current during the forward and reverse switching of the DC motor M.

[0007] Preferably, the normally closed contact KM1 and the normally closed contact KM2 are connected to each other, and one end of the normally closed contact KM1 is connected to one end of the DC voltage positive electrode M1 of the DC motor M, and the normally closed contact KM2 is connected to one end of the DC voltage negative electrode M2 ​​of the DC motor M. The normally closed contact KM1 and the normally closed contact KM2 are connected to the positive electrodes of the freewheeling diode D1 and the freewheeling diode D2 through a wire, and the freewheeling diode achieves a better effect of limiting reverse overvoltage when switching the rotation direction, and has a better protection effect.

[0008] Preferably, both ends of the electromagnetic coil contacts of the contactors KM1 and KM2 are connected to the DC voltage positive electrode M1 and the DC voltage negative electrode M2 ​​of the DC motor M to control the start and stop of the DC motor. When the contactor is in a closed state, it allows current to pass, thereby connecting the circuit; when it is in an open state, it disconnects the current path and prevents the flow of current.

[0009] Compared with the prior art, the technical effects and advantages of the utility model are as follows: the forward and reverse DC motor and freewheeling diode protection circuit controls the forward and reverse start and stop of the DC motor M through the freewheeling diode D1, the freewheeling diode D2 and the contactor KM1, the contactor KM2. When the contactor KM1 is closed and the contactor KM2 is disconnected, the DC motor M rotates forward. At the moment of power failure, the current maintains the DC voltage positive electrode M1 to flow to the DC voltage negative electrode M2, and the contact KM2 is often closed, the freewheeling diode D1 returns to the DC voltage positive electrode M1, and the current is completely limited. The reverse potential is controlled, contactor KM2 is closed, contactor KM1 is disconnected, and DC motor M reverses. At the moment of power failure, the current maintains the flow from the negative DC voltage M2 to the positive DC voltage M1, and the contact KM1 is often closed, the freewheeling diode D2 returns to the negative DC voltage M2, completely limiting the reverse potential, thereby protecting DC motor M, preventing the reverse induced potential of DC motor M at the moment of switching, and generating excessively high voltage pulses that will damage the motor and cause other faults, further improving the service life of the DC motor and reducing the failure rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the utility model. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0012] See also Figure 1The utility model provides a technical solution: a forward and reverse DC motor and freewheeling diode protection circuit, comprising a DC motor M, and freewheeling diodes D1 and D2 connected to the positive and negative poles of the DC motor M. In the circuit, when the current is suddenly interrupted, a reverse voltage will be generated, which may damage other components, and a low-impedance path can be provided to allow the current in the inductive load to continue to flow, thereby preventing the generation of a reverse voltage. The negative poles of the freewheeling diodes D1 and D2 are connected with normally closed contacts KM1 and KM2, so that the circuit can be switched on and off, which is very useful when it is necessary to keep the circuit closed when a power failure occurs. The DC voltage positive pole M1 end and the DC voltage negative pole M2 end of the DC motor M are connected with contactors KM1 and KM2 for limiting the reverse potential of the DC motor M in forward and reverse rotation. When the contactors are closed, the fixed contacts and the moving contacts are in contact to form a closed loop; and when the contactors are opened, they are separated to disconnect the circuit connection.

[0013] One end of the contactor KM1 is connected to one end of the contactor KM2, wherein one end of the contactor KM1 and the contactor KM2 are connected to the normally closed contact KM1 and the normally closed contact KM2, the cathode of the freewheeling diode D1 is connected to one end of the DC voltage positive electrode M1 of the DC motor M, the cathode of the freewheeling diode D2 is connected to one end of the DC voltage negative electrode M2 ​​of the DC motor M, and the anode of the freewheeling diode D1 is connected to the anode of the freewheeling diode D2, and the normally closed contact KM1 and the normally closed contact KM2 are mutually connected. The normally closed contact KM1 and the normally closed contact KM2 are connected, and one end of the normally closed contact KM1 is connected to one end of the DC voltage positive electrode M1 of the DC motor M, and the normally closed contact KM2 is connected to one end of the DC voltage negative electrode M2 ​​of the DC motor M. The normally closed contact KM1 and the normally closed contact KM2 are connected to the positive electrodes of the freewheeling diodes D1 and D2 through a wire, and the two ends of the electromagnetic coil contacts of the contactor KM1 and the contactor KM2 are connected to the DC voltage positive electrode M1 and the DC voltage negative electrode M2 ​​of the DC motor M to control the start and stop of the DC motor.

[0014] Specifically, when in use, when contactor KM1 is closed and contactor KM2 is disconnected, the DC voltage positive pole M1 is positive and the DC voltage negative pole M2 is negative, and the DC motor M rotates forward. At this moment of power failure, the current of the DC motor M maintains the DC voltage positive pole M1 flowing toward the DC voltage negative pole M2, and the contact KM2 is often closed, and the freewheeling diode D1 returns to the DC voltage positive pole M1, completely limiting the reverse potential. When contactor KM2 is closed and contactor KM1 is disconnected, the DC voltage positive pole M1 is negative and the DC voltage negative pole M2 is positive, the DC motor M reverses. At this moment of power failure, the current of the DC motor M maintains the DC voltage negative pole M2 flowing toward the DC voltage positive pole M1, and the contact KM1 is often closed, and the freewheeling diode D2 returns to the DC voltage negative pole M2, completely limiting the reverse potential, thereby protecting the DC motor M, preventing the reverse induced potential of the DC motor M at the switching moment, and generating an excessively high voltage pulse that will damage the motor and cause other faults, further improving the service life of the DC motor and reducing the failure rate.

[0015] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A forward and reverse DC motor and freewheeling diode protection circuit, comprising a DC motor M, and a freewheeling diode D1 and a freewheeling diode D2 connected to the positive and negative electrodes of the DC motor M, characterized in that: The cathodes of the freewheeling diodes D1 and D2 are connected to the normally closed contacts KM1 and KM2, and the DC voltage positive electrode M1 and DC voltage negative electrode M2 ​​of the DC motor M are connected to the contactors KM1 and KM2 for limiting the reverse potential of the DC motor M in forward and reverse rotation.

2. A forward and reverse DC motor freewheeling diode protection circuit according to claim 1, characterized in that: One end of the contactor KM1 is connected to one end of the contactor KM2, wherein one end of the contactor KM1 and the contactor KM2 are connected to the normally closed contact KM1 and the normally closed contact KM2.

3. A forward and reverse DC motor freewheeling diode protection circuit according to claim 1, characterized in that: The cathode of the freewheeling diode D1 is connected to one end of the DC voltage positive electrode M1 of the DC motor M, the cathode of the freewheeling diode D2 is connected to one end of the DC voltage negative electrode M2 ​​of the DC motor M, and the anode of the freewheeling diode D1 is connected to the anode of the freewheeling diode D2.

4. A forward and reverse DC motor freewheeling diode protection circuit according to claim 1, characterized in that: The normally closed contact KM1 and the normally closed contact KM2 are connected to each other, and one end of the normally closed contact KM1 is connected to one end of the DC voltage positive electrode M1 of the DC motor M, and the normally closed contact KM2 is connected to one end of the DC voltage negative electrode M2 ​​of the DC motor M. The normally closed contact KM1 and the normally closed contact KM2 are connected to the positive electrodes of the freewheeling diodes D1 and D2 through a wire.

5. A forward and reverse DC motor freewheeling diode protection circuit according to claim 1, characterized in that: The two ends of the electromagnetic coil contacts of the contactor KM1 and the contactor KM2 are connected to the DC voltage positive electrode M1 and the DC voltage negative electrode M2 ​​of the DC motor M to control the start and stop of the DC motor.

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