CN203708166U - Low-voltage motor control system - Google Patents

Abstract

The utility model discloses a low-voltage motor control system, which comprises an electric power loop and an ZKK control loop; the power circuit consists of a molded case circuit breaker, a primary plug-in and a motor load which are sequentially connected from a three-phase alternating current power supply A, B, C phase line; the ZKK control loop comprises a ZKK electric operating mechanism powered by a direct current power supply, and at least one group of closing loop and opening loop connected with the ZKK electric operating mechanism, wherein the ZKK electric operating mechanism is used for controlling the closing and opening of the molded case circuit breaker. The scheme of configuring the electric operating mechanism for the molded case circuit breaker has a space requirement which is much smaller than that of the original contactor scheme; the scheme that the plastic shell is provided with the electric operating mechanism not only meets the original control requirement, but also simplifies secondary configuration, has larger space in the drawer, is more beneficial to normal heat dissipation when the equipment runs, and is beneficial to long-term safe running of the equipment.

Description

A low-voltage motor control system

technical field

The utility model relates to the field of low-voltage power distribution, in particular to a low-voltage motor control system.

Background technique

Most of the 380V low-voltage motors in power plant projects are controlled by contactors. Generally, closing and tripping relays are used to separate the closing circuit and tripping circuit. The power circuit is shown in Figure 1, and the electrical control circuit diagram is shown in Figure 2; the working principle of the control circuit:

a. Start: the control circuit miniature circuit breaker DK is energized. If the transfer switch ZK is switched to the local position, the connection between ZK: 3 and ZK: 4 will be connected. Because the control circuit of the tripping relay TJ is in the disconnected state, it will be closed at this time. The TJ closed point in the gate circuit remains unchanged. If the closing button HA is pressed, the closing relay coil is energized, and the HJ open point in the contactor control circuit is closed, and the TJ closed point in the contactor circuit remains closed (because the tripping relay TJ The control circuit is in the disconnected state and all the contact states remain unchanged), at this time the contactor coil is energized and moves, and the C open point in the contactor control circuit is closed, so the contactor closing signal is maintained and the contactor can be kept closed In normal operation, the molded case circuit breaker at the upper end of the contactor and the main switch in the circuit are in the closed state. After the contactor is closed, the load at the lower end is energized and operates normally (if the transfer switch ZK is switched to the remote state, then ZK: 1, ZK : 2 is connected, after the DCS terminal sends the start command, the program is the same as that after the HA is closed, so that the contactor C is finally closed and the closed state is maintained through the self-holding point);

b. Shutdown: connect to state a, if it is necessary to stop the operation of the load at the lower end of the circuit, the shutdown can be realized by the following operations: If the transfer switch ZK is switched to the local position, then ZK:3 and ZK:4 are connected, and the trip button TA is pressed. The TJ coil of the relay is energized, and the TJ closed point action in the control circuit of the contactor coil becomes an open point to disconnect the contactor coil circuit, the contactor coil loses power and returns (tripping), and the lower end load stops due to power loss (if When the transfer switch ZK is switched to the remote state, ZK: 1 and ZK: 2 are connected. After the DCS end sends a start command, the program is the same as after TA is closed, and the contactor C trips, and the lower end load stops running).

As mentioned above, the control circuit of this type of scheme contains more components, the secondary circuit is more complicated, and the motor circuit is generally installed in a drawer type. Due to the relatively fixed positions of the molded case circuit breakers in the drawers of various drawer cabinets (including MNSG cabinets, GCS, GCK and new general-purpose cabinets), the primary input and output terminals are relatively fixed, so the remaining space in the drawer is very limited. There are too many configurations of sub-components, and a slight improper selection of closing and opening relays will cause the components in the drawer to be installed, or all components are barely installed in the drawer, but it is difficult to dissipate heat during normal operation of the equipment, which will affect the life of the components. And the safety of use is a very big test, and it also lays a lot of hidden dangers for future failures. Then, how to simplify the configuration and achieve the same control requirements under the condition of very limited drawer space is a common concern of many designers.

Utility model content

In order to solve the above technical problems, the purpose of this utility model is to provide a low-voltage motor control system with simplified circuit structure.

The technical scheme that the utility model adopts is:

A low-voltage motor control system, characterized in that:

Including a power loop and a ZKK control loop;

The power circuit is composed of a molded case circuit breaker, a primary plug-in unit, and a motor load sequentially connected from the A, B, and C phase lines of the three-phase AC power supply;

The ZKK control circuit includes a ZKK electric operating mechanism powered by a DC power supply, and at least one combination circuit and opening circuit connected to the ZKK electric operating mechanism. The ZKK electric operating mechanism is used to control the closing and opening of the molded case circuit breaker. Gates and openings.

The closing circuit and the opening circuit have two groups, one group is the closing circuit and the opening circuit controlled locally, and the other group is the closing circuit and the opening circuit controlled remotely.

The closing circuit of the local control is composed of a transfer switch connected in series at both ends of the ZKK electric operating mechanism, a closing button, a travel switch, and a normally closed contact of an intermediate relay; the opening circuit of the local control is composed of a switch connected in series The transfer switch at both ends of the ZKK electric operating mechanism, the opening button, and the normally open contact of the intermediate relay; the closing circuit of the remote control is composed of a transfer switch connected in series at both ends of the ZKK electric operating mechanism, a DCS closing switch, a travel switch, The normally closed contact of the intermediate relay is composed of; the opening circuit of the remote control is composed of a transfer switch connected in series at both ends of the ZKK electric operating mechanism, a DCS opening switch, and a normally open contact of the intermediate relay; the coil of the intermediate relay and the plastic The auxiliary normally open contacts of the case circuit breaker are connected in series with the positive and negative output terminals of the DC power supply.

A non-working position trip switch is connected in parallel with the break-off circuit.

The coil of the intermediate relay and the auxiliary normally open contact of the molded case circuit breaker are connected in series in parallel with a red light indicating circuit and a green light indicating circuit, wherein the red light indicating circuit consists of a red light and an auxiliary normally open contact of the intermediate relay It is formed in series, and the green light indicating circuit is formed by series connection of the green light and the auxiliary normally closed contact of the intermediate relay.

The positive and negative output terminals of the DC power supply are provided with control switches.

The beneficial effects of the utility model:

The low-voltage motor control system of the utility model cancels the contactor configured in the original circuit, and configures the electric operating mechanism for the main switch in the circuit, that is, the molded case circuit breaker; The gate relay HJ, opening relay TJ and contactor C are all cancelled, and the space requirement of the molded case circuit breaker with electric operating mechanism is much smaller than that required by the original contactor scheme; the scheme of molded case circuit breaker with electric operating mechanism not only It meets the original control requirements and simplifies the secondary configuration. The space in the drawer is larger, which is more conducive to the normal heat dissipation of the equipment during operation, and is conducive to the long-term safe operation of the equipment.

Description of drawings

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described further.

Figure 1 is a schematic diagram of the power circuit of a traditional low-voltage motor control system;

Fig. 2 is a schematic diagram of a control loop of a traditional low-voltage motor control system;

Fig. 3 is a schematic diagram of the power circuit of the utility model low-voltage motor control system;

Fig. 4 is a schematic diagram of the control circuit of the low-voltage motor control system of the present invention.

Detailed ways

Referring to Fig. 3 and shown in Fig. 4, it is a kind of low-voltage motor control system of the present utility model, including a power circuit and a ZKK control circuit;

Wherein, the power circuit is composed of a molded case circuit breaker ZKK, a primary plug-in 100, and a motor load D sequentially connected from the three-phase AC power supply A, B, and C phase lines, as shown in Figure 3;

As shown in Figure 4, the ZKK control circuit includes a ZKK electric operating mechanism M powered by DC power supply +KM2, -KM2, and at least one combination and opening circuit connected to the ZKK electric operating mechanism M. The ZKK electric operating mechanism M is used to control the closing and opening of the molded case circuit breaker ZKK. The positive and negative output terminals +KM2 and -KM2 of the DC power supply are provided with a control switch DK. In this example, the control switch DK is a miniature circuit breaker device.

The closing circuit and the opening circuit have two groups, one group is the closing circuit and the opening circuit controlled locally, and the other group is the closing circuit and the opening circuit controlled remotely.

The closing circuit of the local control is composed of the transfer switch ZK connected in series at both ends S1 and S2 of the ZKK electric operating mechanism M, the closing button HA, the travel switch YW, and the normally closed contact of the intermediate relay ZJ; The controlled opening circuit is composed of transfer switch ZK, opening button TA, and intermediate relay ZJ normally open contacts connected in series at both ends S1 and S4 of the ZKK electric operating mechanism M;

The closing circuit of the remote control is composed of the transfer switch ZK connected in series at both ends S1 and S2 of the ZKK electric operating mechanism M, the DCS closing switch, the travel switch YW, and the normally closed contact of the intermediate relay ZJ; the remote control The opening circuit is composed of transfer switch ZK, DCS opening switch, and intermediate relay ZJ normally open contact connected in series at both ends S1 and S4 of the ZKK electric operating mechanism M;

The coil of the intermediate relay ZJ and the auxiliary normally open contact OF/ZKK of the molded case circuit breaker ZKK are connected in series at the positive and negative output terminals of the DC power supply.

The above opening circuit is connected in parallel with a non-working position trip switch SW, which is used to implement a trip command in an emergency or to trip the circuit in conjunction with the upper power supply circuit.

The coil of the intermediate relay and the auxiliary normally open contact OF/ZKK of the molded case circuit breaker ZKK are connected in series in parallel with a red light indicating circuit and a green light indicating circuit, wherein the red light indicating circuit consists of a red light HD and an intermediate relay ZJ The auxiliary normally open contacts of the green light are connected in series, and the green light indicator circuit is formed by the green light LD and the auxiliary normally closed contacts of the intermediate relay ZJ connected in series.

Its working principle is:

a. Start: When the drawer is in the working position, the drawer travel switch YW is closed, and the relay ZJ coil circuit is not connected, so the ZJ contact remains unchanged, that is, ZJ in the ZKK closing circuit remains closed, and the control circuit miniature circuit breaker DK controls the circuit. Electricity, ZKK operating power supply is ready to close, at this time, if the transfer switch ZK is switched to the local position, ZK: 3, ZK: 4 will be connected, press the closing button HA, the ZKK closing circuit will be energized and Closing, because the electric operating mechanism of the molded case circuit breaker is a mechanical self-holding type, after closing, even if HA is reset and disconnected, ZKK can also be self-maintaining. When the switch ZK is switched to the remote state, ZK: 1 and ZK: 2 are connected. After the DCS terminal sends the start command, the program is the same as that after the HA is closed, so that the molded case circuit breaker is closed and the mechanical self-maintains the closed state);

b. Shutdown: connected to state a, after ZKK is closed, its auxiliary point OF is that the action of OF/ZKK in the figure becomes a closed point, after the intermediate relay ZJ coil is energized, the ZJ auxiliary contact acts, and the ZJ open point in the ZKK trip circuit is closed. When the switch ZK is switched to the local position, ZK: 3 and ZK: 4 are connected, and the trip button TA is pressed, the ZKK trip circuit is energized until ZKK trips, and the lower end load stops due to power loss (if the transfer switch ZK is switched to the remote In the state, ZK: 1 and ZK: 2 are connected, and after the DCS terminal sends a start command, the program is the same as that after TA is closed, causing the molded case circuit breaker ZKK to trip, and the lower end load to stop running).

The low-voltage motor control system of the utility model cancels the contactor configured in the original circuit, and configures the electric operating mechanism for the main switch in the circuit, that is, the molded case circuit breaker; The gate relay HJ, the opening relay TJ and the contactor C are cancelled. The space requirement of the molded case circuit breaker with electric operating mechanism is much smaller than that of the original contactor scheme; the molded case circuit breaker with electric operating mechanism is not only It meets the original control requirements and simplifies the secondary configuration. The space in the drawer is larger, which is more conducive to the normal heat dissipation of the equipment during operation, and is conducive to the long-term safe operation of the equipment. This solution is a good solution for drawer renovation or drawer with limited space and must be closed and opened by remote control.

The above is only the preferred implementation of the utility model, the utility model is not limited to the above implementation, as long as the technical solutions to achieve the purpose of the utility model by basically the same means are within the scope of protection of the utility model.

Claims (6)

1. A low-voltage motor control system, characterized in that: Including a power loop and a ZKK control loop; The power circuit is composed of a molded case circuit breaker, a primary plug-in unit, and a motor load sequentially connected from the A, B, and C phase lines of the three-phase AC power supply; The ZKK control circuit includes a ZKK electric operating mechanism powered by a DC power supply, and at least one combination circuit and opening circuit connected to the ZKK electric operating mechanism. The ZKK electric operating mechanism is used to control the closing and opening of the molded case circuit breaker. Gates and openings. 2. A low-voltage motor control system according to claim 1, characterized in that: the closing circuit and the opening circuit have two groups, one group is the closing circuit and the opening circuit controlled locally, and the other The group is the closing circuit and opening circuit of remote control. 3. A low-voltage motor control system according to claim 2, characterized in that: the closing circuit of the local control is composed of a transfer switch, a closing button, a travel switch, and a middle switch connected in series at both ends of the ZKK electric operating mechanism. The normally closed contact of the relay is composed of; the opening circuit of the local control is composed of a transfer switch connected in series at both ends of the ZKK electric operating mechanism, the opening button, and the normally open contact of the intermediate relay; the closing circuit of the remote control is composed of The transfer switch connected in series at both ends of the ZKK electric operating mechanism, the DCS closing switch, the travel switch, and the normally closed contact of the intermediate relay are composed; The opening switch is composed of a normally open contact of an intermediate relay; the coil of the intermediate relay and the auxiliary normally open contact of the molded case circuit breaker are connected in series at the positive and negative output terminals of the DC power supply. 4. A low-voltage motor control system according to claim 2, characterized in that: said opening circuit is connected in parallel with a non-working position trip switch. 5. A low-voltage motor control system according to claim 3, characterized in that: the series circuit formed by the coil of the intermediate relay and the auxiliary normally open contact of the molded case circuit breaker is connected in parallel with a red light indicating circuit and a green light indicating circuit, wherein the red light indication circuit is formed by series connection of the red light and the auxiliary normally open contact of the intermediate relay, and the green light indication circuit is formed by series connection of the green light and the auxiliary normally closed contact of the intermediate relay. 6. A low-voltage motor control system according to any one of claims 1-5, characterized in that: the positive and negative output terminals of the DC power supply are provided with control switches.