A time-delay relay for a motor control circuit

Abstract

A time-delay relay for a motor control circuit is provided with a rectification module, a comparison circuit, a relay coil and a trip contact, and a monostable circuit. The input end of the monostable circuit is connected to an auxiliary contact S1. The comparison circuit is connected to the relay coil after passing through an amplification circuit. The trip contact controlled by the relay coil is connected in series in the motor control circuit. The rectification module is used for input of AC or DC power supply, and the AC and DC control circuits are common.

Description

Technical Field

[0001] The present invention relates to a relay, and particularly to a relay with a time-delay protection for a motor control circuit. Background Art

[0002] In the existing motor control circuit, the motor position is mainly judged according to the travel switch or other position signals. However, due to the harsh on-site use environment or other factors leading to misjudgment of the position signal, the motor operation will be abnormal and the equipment will be damaged. Therefore, auxiliary contacts need to be added to protect the motor and improve the safety and reliability of the application environment. However, there are no other resources on site, and there is no solution on how to control the auxiliary contacts, where the control power supply of the auxiliary contacts comes from, and how to set the time-delay protection time. Summary of the Invention

[0003] Object of the Invention: In order to overcome the harsh on-site use environment and lack of resources, a series-connected time-delay relay for a motor control circuit is provided. When "electric hold" occurs in the motor control circuit, the time-delay function is started. When the set time is reached, the "electric hold" is released. Only the negative terminal of the motor control circuit needs to be disconnected and this module is connected in series, without the need to externally connect a power supply device again. The power supply for this module's control is completely from the control circuit itself, and it is small in size and convenient to install. It solves the problem that in the actual environment, due to factors in the control circuit itself, the motor control is abnormal but the control circuit cannot be disconnected in time.

[0004] Technical Solution: To achieve the above object, the technical solution adopted by the present invention is as follows: A time-delay relay for a motor control circuit, characterized in that: it is provided with a rectification module, a comparison circuit, a relay coil and a make contact, and a monostable circuit. The input end of the monostable circuit is connected to an auxiliary contact S1, and the comparison circuit is connected to the relay coil through an amplification circuit. The relay coil and the make contact controlled by the relay coil are connected in series in the motor control circuit.

[0005] The rectification module is used for AC or DC power input, and the AC and DC control circuits are common.

[0006] When the current in the motor control circuit is not less than 50 mA, the relay time-delay function can be started, and it has a time-delay setting, and the required time-delay protection time can be set according to customer requirements.

[0007] The set range of the time-delay protection time set by the monostable circuit is 1 s to 20 s.

[0008] Two-stage jumpers are set. Among them, there is a jumper at the position of a switch S1 in the output of the monostable circuit, which is the first-stage jumper; if the switch is short-circuited, the time-delay is 5 s, which is the second-stage jumper. If not connected, the time-delay is 10 s; the time-delay is set according to customer requirements. The conventional time-delays are two gears of 5 s and 10 s; the working current at the input end of the monostable circuit is above 50 mA.

[0009] Application of the time-delay relay, with the time-delay protection time setting range of 1 s to 20 s. Just disconnect the negative terminal of the motor control circuit and connect this product in series; when this time-delay relay is connected in series to the motor control circuit, when the motor circuit is working, the current in the control circuit is not less than 50 mA, the time-delay protection circuit is started and starts to delay. If the motor control circuit automatically releases the self-locking within the set time-delay range, the current in the control circuit is 0, the relay remains normally closed, and the time-delay is cleared; if the time-delay arrives and the motor control circuit does not automatically release the self-locking, the normally closed contact of the relay disconnects, the self-locking release circuit is released, the current in the control circuit is 0, and the relay contact closes again; the open contact controlled by the relay coil is connected in series to the motor control circuit.

[0010] As a time-delay protection device for the motor operation circuit, when the "electrical hold" appears in the motor control circuit, the time-delay function is started, and when the set time-delay is reached, the "electrical hold" is released. It is mainly applied to the situation where the motor circuit is in a long-term "electrical hold" due to its own reasons or the auxiliary contacts are not in place for a long time, which will cause abnormal motor operation. At this time, as long as the set time-delay of this product is reached, the motor circuit can still be cut off, thus ensuring the safety of the circuit. It includes a housing, a power supply inlet end, a comparison circuit, a monostable circuit, a rectifier bridge, a relay open circuit, and a coil. When the motor operation is abnormal due to its own reasons, this product can provide auxiliary contacts to protect the motor control circuit with time delay. This time-delay relay is applicable to all occasions that require auxiliary protection for the motor control circuit.

[0011] Beneficial effects: Therefore, the product of the present invention can provide auxiliary protection for the motor control circuit, solve the problem when the "electrical hold" fault appears in the motor control circuit, improve the reliability of the system, and has a small volume, is installed on the guide rail, and is convenient for transformation and use. Description of the Drawings

[0012] Figure 1 Internal schematic diagram of the time-delay relay for the motor control circuit;

[0013] Figure 2 Wiring diagram of the time-delay relay for the motor control circuit. Detailed Embodiment

[0014] The present invention will be further described below with reference to the drawings.

[0015] Figure 1 Internal circuit schematic diagram of the time-delay relay for the motor control circuit, Figure 1This is the delay relay circuit of the control loop of the present invention. The circuit is provided with a rectification module D1, a comparison circuit, a monostable circuit, resistors and capacitors, a relay coil REL1 and a trip contact. When the input power supply is AC or DC, the delay relay is connected to the control loop. As long as the current in the control loop is not less than 50 mA, the delay protection function can be started. The specific delay time can be set according to the actual situation on site. U1 is a monostable chip used for delaying. At the moment of power-on, the triode Q2 conducts, so the third pin of U1 is at a high level. Until the delay time of the monostable circuit arrives, the third pin of U1 outputs a low level, then the triode Q1 conducts, the relay coil has 5V power, the relay contact disconnects, and the control loop is powered off, thus playing a role in delay protection. D2 is a 5.1V zener diode, D3 is a 2.4V zener diode, and D4 is a 1N4007, which are used to protect the relay coil.

[0016] In the actual use of the present invention, the delay relay is connected in series to the motor control loop. When the motor loop is working and the current in the control loop is not less than 50 mA, the delay protection circuit is started and the delay begins. If the motor control loop automatically releases the self-locking within the set delay time range, the current in the control loop becomes 0, the relay remains in the normally closed state, and the delay time is cleared. If the delay time arrives and the motor control loop does not automatically release the self-locking, the normally closed contact of the relay disconnects, the self-locking loop is released, the current in the control loop becomes 0, and the relay contact closes again. The trip contact controlled by the relay coil is connected in series to the motor control loop. The delay time of the delay relay DTM is set to 10 s. Figure 1 In which the S1 switch is disconnected, and U1 is the signal output by the monostable chip and is connected according to the appendix Figure 2 to the motor control loop that can be used for both AC and DC 220V ([[]]END]] Figure 2 in which A1 and A2 respectively correspond to Figure 1 the inout power input terminals in

[0017] Embodiment 1:

[0018] Set the delay time of the delay relay to 10 s (the S1 switch is disconnected, and the delay time is jointly determined by R5 and C5. At power-on, the monostable circuit is triggered to start the delay. Until the delay time arrives, the third pin of U1 changes from a high level to a low level, causing Q1 to conduct, the relay coil is energized, and the relay contact disconnects.), and connect it according to the appendix Figure 2It is connected to a motor control circuit that can be powered by both AC and DC 220V. At the same time, power the control circuit with AC 220V, perform the closing operation, and then artificially make the position of the travel switch abnormal so that the control circuit continuously controls the motor to rotate. It can be seen that when the delay of 10s arrives, the motor stops rotating, and the protection is effective.

[0019] Embodiment 2:

[0020] Set the delay time of the time-delay relay to 10s and follow the appendix Figure 2 It is connected to a motor control circuit that can be powered by both AC and DC 220V. At the same time, power the control circuit with DC 220V, perform the closing operation, and then artificially make the position of the travel switch abnormal so that the control circuit continuously controls the motor to rotate. It can be seen that when the delay of 10s arrives, the motor stops rotating, and the protection is effective. The travel switch is the position signal contact of the motor control circuit itself. Simulate that the travel switch is not in place and see if the time-delay relay can play a protective role.

[0021] Embodiment 3:

[0022] Set the delay time of the time-delay relay to 10s and follow the appendix Figure 2 It is connected to a motor control circuit that can be powered by both AC and DC 220V. At the same time, power the control circuit with DC 220V, perform the closing operation, and the motor runs normally. Ensure that the motor stop rotation time is less than the set delay of 10s, then the delay time is cleared and the next operation starts timing again. K is the relay control circuit, and DTM is the time-delay relay module.

[0023] The above are only the embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A time-delay relay for a motor control circuit, characterized in that: There are a rectification module, a comparison circuit, resistors and capacitors, a relay coil and a make contact, a monostable circuit, and a delay circuit; the rectification module D1, the comparison circuit, the monostable circuit, and the delay circuit are connected in sequence. The comparison circuit is composed of transistor circuits Q1 and Q2. The input end of the monostable circuit is connected to the auxiliary contact S1. The comparison circuit is connected to the relay coil after passing through an amplification circuit. The make contact controlled by the relay coil is connected in series in the motor control circuit. When the input power supply is AC or DC, a time-delay relay is connected to the control circuit. As long as the current in the control circuit is not less than 50 mA, the time-delay protection function is started. The specific delay time is set according to the actual situation on site. In the monostable circuit, the monostable chip U1 and the connected capacitor C5 and resistor R5 form a delay circuit for delaying. At the moment of power-on, the Q2 transistor of the comparison circuit conducts, so the third pin of U1 is at a high level. Until the delay time of the monostable circuit arrives, the third pin of U1 outputs a low level, then the Q1 transistor of the comparison circuit conducts, the relay coil has 5V power, the relay contact disconnects, and the control circuit loses power, thus playing a role in time-delay protection. There is a zener diode to protect the relay coil; The time-delay relay is connected in series to the motor control circuit. When the motor circuit works, the delay starts. If the motor control circuit automatically releases the self-locking within the set delay time range, the current in the control circuit is 0, and the relay remains in the normally closed state, and the delay time is cleared. If the delay time arrives and the motor control circuit does not automatically release the self-locking, the normally closed contact of the relay disconnects, the self-locking circuit will be released, the current in the control circuit is 0, and the relay contact closes again; the make contact controlled by the relay coil is connected in series in the motor control circuit; Q1 and Q2 are transistors and both work in the saturation state.

2. The time delay relay according to claim 1, wherein: The rectification module is used for AC or DC power input.

3. The time delay relay according to claim 1, characterized in that: The set range of the delay protection time set by the monostable circuit is 1 s to 20 s.

4. The time delay relay according to claim 1, wherein: There are two-position jumpers. Among them, there is a switch S1 at the output of the monostable circuit. The position of the jumper at one place is the first-stage jumper; if the switch is short-circuited, the delay time is 5S, which is the second-stage jumper. If it is not connected, the delay time is 10S; The delay time is set according to the customer's requirements. The conventional delay times are two gears: 5s and 10s; the operating current at the input end of the monostable circuit is above 50 mA.

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