A contactor winding undervoltage protection module

Abstract

The utility model discloses a contactor winding undervoltage protection module, including a varistor, a rectifier bridge and a MOS tube, wherein a first varistor is connected to a contactor start winding coil through a rectifier bridge, a second varistor is connected in parallel with the MOS tube and then connected in series with the contactor start winding coil and the rectifier bridge to form a complete closed circuit, the MOS tube provides and protects voltage input through a voltage regulator tube, the power supply end of the contactor winding is connected to the input end of the rectifier bridge through the first varistor, the positive pole of the output end of the rectifier bridge is connected to one end of the contactor start winding coil, the other end of the contactor start winding coil is connected to the source of the MOS tube, and the drain of the MOS tube is connected to the negative pole of the rectifier bridge. The utility model has low requirements for the power supply of the contactor winding, does not need to distinguish between the positive and negative poles of the power supply, controls the conduction and shutdown of the MOS tube through the threshold start voltage of the first voltage regulator tube, and realizes that under undervoltage, a single winding can achieve a high release voltage, and a double winding can achieve the purpose of protecting the start winding.

Description

Technical Field

[0001] The utility model relates to the technical field of contactors, in particular to a contactor winding undervoltage protection module. Background Art

[0002] The contactor needs to achieve wide voltage range pull-in. If the single-winding contactor wants to achieve wide voltage range pull-in, the winding power needs to be relatively high, but the release voltage is relatively low. For the double-winding contactor, the pull-in winding has fewer turns and the holding winding has more turns. The pull-in winding is energized at the moment of connection. After connection, the pull-in winding and the holding winding are energized, and the auxiliary contact is disconnected. Therefore, it will not overheat during long-term operation. However, if the power supply voltage is low and the pull-in force is insufficient, the pull-in winding will be energized, but the auxiliary contact cannot be disconnected, so that the contactor start winding is always in a high current state or the contactor is repeatedly switched in the start-up hold state. After a long time, it will cause the start winding to burn or the auxiliary contact to stick. At present, most undervoltage protection circuits are judged by voltage sampling and voltage comparison through chips or comparators. The circuit is relatively complex and the reliability is low. Utility Model Content

[0003] In view of the above-mentioned shortcomings and deficiencies, the utility model provides a contactor winding undervoltage protection module, which has low requirements for the contactor winding power supply, does not need to distinguish between the positive and negative poles of the power supply, can also be powered by AC, and only needs to replace components to change the undervoltage action voltage, making it more convenient to change the action threshold.

[0004] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0005] A contactor winding undervoltage protection module, characterized in that it includes a first and a second varistor, a rectifier bridge and a MOS tube, the first varistor is connected to the contactor starting winding coil through the rectifier bridge, the second varistor is connected in parallel with the MOS tube and then connected in series with the contactor starting winding coil and the rectifier bridge to form a complete closed circuit, and the MOS tube provides and protects voltage input through a voltage regulator tube.

[0006] The first and second power supply ends of the contactor winding are respectively connected to the AC side input end of the rectifier bridge through the first varistor, the positive pole of the DC side output end of the rectifier bridge is connected to one end of the contactor starting winding coil, the other end of the contactor starting winding coil is connected to the source of the MOS tube, the drain of the MOS tube is connected to the negative pole of the rectifier bridge, and the second varistor is connected in parallel to the source and drain of the MOS tube.

[0007] The voltage regulator tube includes first and second voltage regulator tubes, and the DC side output end of the rectifier bridge is provided with a first resistor, a first voltage regulator tube and a second voltage regulator tube which are connected in series and in parallel as a whole between the positive and negative electrodes of the rectifier bridge.

[0008] The positive electrode of the DC output end of the rectifier bridge is connected to one side of the first resistor, the other side of the first resistor is connected to the negative electrode of the first voltage regulator tube, the positive electrode of the first voltage regulator tube is connected to the negative electrode of the second voltage regulator tube, the negative electrode of the second voltage regulator tube is connected to the negative electrode of the output end of the rectifier bridge, and the second voltage regulator tube, the first voltage regulator tube, and the first resistor are connected in series and connected in parallel to the positive and negative electrodes of the rectifier bridge as a whole.

[0009] The gate and drain of the MOS tube are connected in parallel with a second voltage regulator tube, a second resistor and a capacitor; the gate of the MOS tube is connected to the positive electrode of the first voltage regulator tube and the negative electrode of the second voltage regulator tube.

[0010] The utility model has the following beneficial effects and advantages:

[0011] 1. The utility model has low requirements for the power supply of the contactor winding, does not need to distinguish the positive and negative poles of the power supply, can also be powered by AC, and only needs to replace the components to change the undervoltage action voltage, which is more convenient to change the action threshold;

[0012] 2. Through the threshold turn-on voltage of the first voltage regulator tube VD1, the on and off of the MOS tube Q1 is controlled, so that under undervoltage, the single winding can achieve a high release voltage, and the double winding can achieve the purpose of protecting the starting winding;

[0013] For single-winding contactors, the contactor can be prevented from working when the voltage is lower than a certain voltage while ensuring a high pull-in voltage range, thus releasing a higher voltage; for double-winding contactors, the contactor can be prevented from working when the voltage is lower than a certain voltage due to insufficient switching of the auxiliary contacts, and no current will flow through the winding, thereby protecting the starting winding and auxiliary contacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the schematic diagram of the contactor winding undervoltage protection module.

[0015] Among them, A1 is the first power supply end of the contactor winding, A2 is the second power supply end of the contactor winding, BR1 is a rectifier bridge, R1 is a resistor, C1 is a capacitor, VD1 is a first voltage regulator tube, VD2 is a second voltage regulator tube, ZNR1 is a first varistor, ZNR2 is a second varistor, Q1 is a MOS tube, and L1 is a contactor starting winding coil. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings of the specification. Figure 1As shown, the utility model is a contactor winding undervoltage protection module, including first and second varistors, a rectifier bridge and a MOS tube. The first varistor is connected to the contactor starting winding coil through the rectifier bridge, and the second varistor is connected in parallel with the MOS tube and then connected in series with the contactor starting winding coil and the rectifier bridge to form a complete closed circuit. The MOS tube provides and protects voltage input through a voltage regulator tube.

[0017] The first and second power supply terminals A1 and A2 of the contactor winding are respectively connected to the AC side input terminal of the rectifier bridge BR1 through the first varistor ZNR1, the positive pole of the DC side output terminal of the rectifier bridge BR1 is connected to one end of the contactor starting winding coil L1, the other end of the contactor starting winding coil L1 is connected to the source of the MOS tube Q1, the drain of the MOS tube Q1 is connected to the negative pole of the rectifier bridge BR1, and the second varistor ZNR2 is connected in parallel to the source and drain of the MOS tube Q1.

[0018] The voltage regulator tube includes a first and a second voltage regulator tube VD1 and VD2. The positive electrode of the DC side output end of the rectifier bridge BR1 is connected to one side of the first resistor R1, and the other side of the first resistor R1 is connected to the negative electrode of the first voltage regulator tube VD1. The positive electrode of the first voltage regulator tube VD1 is connected to the negative electrode of the second voltage regulator tube VD2, and the negative electrode of the second voltage regulator tube VD2 is connected to the negative electrode of the output end of the rectifier bridge BR1. The second voltage regulator tube VD2, the first voltage regulator tube VD1, and the first resistor R1 are connected in series and connected in parallel to the positive and negative electrodes of the rectifier bridge BR1 as a whole.

[0019] The gate and drain of the MOS tube Q1 are connected in parallel with a second voltage regulator tube VD2, a second resistor R2 and a capacitor C1; the gate of the MOS tube Q1 is connected to the positive electrode of the first voltage regulator tube VD1 and the negative electrode of the second voltage regulator tube VD2.

[0020] The threshold turn-on voltage of the first voltage regulator tube VD1 is used to control the on and off of the MOS tube Q1, so that under undervoltage, the single winding can achieve a high release voltage, and the double winding can achieve the purpose of protecting the starting winding; the function of the rectifier bridge BR1 is to make the input power supply not distinguish between positive and negative poles and AC and DC; the first varistor ZNR1 is overvoltage protection; the first resistor R1 plays a role in current limiting, limiting the current on the first voltage regulator tube VD1; the second voltage regulator tube VD2 and the capacitor C1 and the second resistor R2 constitute the gate startup protection circuit of the MOS tube Q1; the second varistor ZNR2 protects the MOS tube Q1.

Claims

1. A contactor winding undervoltage protection module, characterized in that: It includes first and second varistors, a rectifier bridge and a MOS tube. The first varistor is connected to the contactor starting winding coil through the rectifier bridge. The second varistor is connected in parallel with the MOS tube and then connected in series with the contactor starting winding coil and the rectifier bridge to form a complete closed circuit. The MOS tube provides and protects voltage input through a voltage regulator tube.

2. The contactor winding undervoltage protection module according to claim 1, characterized in that: The first and second power supply ends of the contactor winding are respectively connected to the AC side input end of the rectifier bridge through the first varistor, the positive pole of the DC side output end of the rectifier bridge is connected to one end of the contactor starting winding coil, the other end of the contactor starting winding coil is connected to the source of the MOS tube, the drain of the MOS tube is connected to the negative pole of the rectifier bridge, and the second varistor is connected in parallel to the source and drain of the MOS tube.

3. The contactor winding undervoltage protection module according to claim 1, characterized in that: The voltage regulator tube includes first and second voltage regulator tubes, and the DC side output end of the rectifier bridge is provided with a first resistor, a first voltage regulator tube and a second voltage regulator tube which are connected in series and in parallel as a whole between the positive and negative electrodes of the rectifier bridge.

4. The contactor winding undervoltage protection module according to claim 3, characterized in that: The positive electrode of the DC output end of the rectifier bridge is connected to one side of the first resistor, the other side of the first resistor is connected to the negative electrode of the first voltage regulator tube, the positive electrode of the first voltage regulator tube is connected to the negative electrode of the second voltage regulator tube, the negative electrode of the second voltage regulator tube is connected to the negative electrode of the output end of the rectifier bridge, and the second voltage regulator tube, the first voltage regulator tube, and the first resistor are connected in series and connected in parallel to the positive and negative electrodes of the rectifier bridge as a whole.

5. The contactor winding undervoltage protection module according to claim 1, characterized in that: The gate and drain of the MOS tube are connected in parallel with a second voltage regulator tube, a second resistor and a capacitor; the gate of the MOS tube is connected to the positive electrode of the first voltage regulator tube and the negative electrode of the second voltage regulator tube.

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