CN204886397U - A backup power automatic switching circuit - Google Patents

Abstract

The utility model provides a stand -by power supply automatic switch -over circuit, includes an ac contactor (b) KM1 (b) and the 2nd ac contactor KM2, the switching circuit is including postponing control circuit, it has included auxiliary relay KA1, time relay KT1, relay KA2 to postpone control circuit. Postpone control circuit through setting up to it has corresponding delay at the in -process that stand -by power supply is switching to make, and sets up the start -up that stand -by power supply was controlled to auxiliary relay, time relay and relay through the centre in circuit arrangement, makes the reliability of circuit increase simple structure.

Description

A backup power automatic switching circuit

technical field

The utility model relates to the field of equipment power supply control, in particular to an automatic switching circuit for a standby power supply.

Background technique

In some production equipment, if the line fails, there will be no electricity available on the production line, which will bring great losses to production, so it is necessary to increase the backup power supply. When the line of the main power supply connected to the grid fails, the backup power supply can be automatically switched to production for production.

In the prior art, the switching of the backup power supply is generally carried out by using a group of AC contactors. The normally closed contact of the AC contactor is connected between the backup power supply and the equipment, and the coil of the AC contactor is connected to the main power circuit. When the main power supply Under normal circumstances, the coil end of the AC contactor drives the contacts to open. At this time, the main power supply is supplied. When the main power is cut off, the contact end of the AC contactor is closed again, and the backup power is cut off. Although this method can solve the problem of the main power failure. Switching between the backup power supply and the backup power supply, but the delayed switching and power cut are not considered. If the circuit controlling the switching of the backup power supply can consume as little energy as possible, the utilization rate will be greatly improved.

Utility model content

The technical problem to be solved by the utility model is to provide an automatic switching circuit for standby power supply with low energy consumption, simple structure, reliable control and high efficiency.

In order to solve the above technical problems, the utility model provides an automatic switching circuit for standby power supply, which includes a first AC contactor KM1 and a second AC contactor KM2, the first AC contactor includes a main contact KM1-1, the The main contact KM1-1 is connected between the main power supply and the electrical equipment, the second AC contactor includes the main contact KM2-1, and the main contact KM2-1 is connected between the backup power supply and the electrical equipment During the period, the coil end of the first AC contactor KM1 is connected to the main power circuit, the switching circuit includes a delay control circuit, and the delay control circuit includes an intermediate relay KA1, a time relay KT1, a relay KA2, a power module and a non- The first AC contactor includes an auxiliary contact KM1-2, the coil end of the intermediate relay KA1 is connected in series with the auxiliary contact KM1-2 in the backup power circuit, and the relay KA1 includes a first contact KA1-1, and the second contact KA1-2, the first contact KA1-1 is connected in series with the coil end of the time relay KT1 in the backup power circuit, the second contact KA1-2 is connected to the power module The input end is connected in series to the standby power circuit, the output end of the power module is connected to a NOT gate, the contact KT1-1 of the time relay KT1 is connected in series between the input of the NOT gate and the ground of the power module, and the output terminal of the NOT gate The coil end of the relay KA2 is controlled, and the contact KA2-1 of the relay KA2 is connected in series with the coil end of the second AC contactor KM2 in the backup power circuit.

Preferably, the second AC contactor KM2 includes an auxiliary contact KM2-2, the auxiliary contact KM2-2 is connected in series with the coil end of the first AC contactor KM1, and the auxiliary contact KM2-2 is in a normal state For normally closed contacts.

Preferably, the second AC contactor KM2 includes an auxiliary contact KM2-3, and the auxiliary contact KM2-3 is connected in series with the coil end of the time relay KT1.

Preferably, the second AC contactor KM2 includes an auxiliary contact KM2-4, and the auxiliary contact KM2-4 is connected in parallel with the contact KA2-1 of the relay KA2.

Preferably, the second AC contactor KM2 includes an auxiliary contact KM2-5, and the auxiliary contact KM2-5 is connected in series with the coil end of the intermediate relay KA1.

Preferably, the auxiliary contacts KM2-3 and KM2-5 are normally closed contacts under normal conditions, and the auxiliary contacts KM2-4 are normally open contacts under normal conditions

Preferably, the power module includes a transformer and a rectification and voltage stabilization circuit, and the output of the NOT gate drives the relay KA2 through a triode.

Preferably, the main contact KM1-1, the main contact KM2-1, the first contact KA1-1, the second contact KA1-2, the contact KT1-1, and the contact KA2-1 are normally A normally open contact, the auxiliary contact KM1-2 is a normally closed contact under normal conditions.

Beneficial effects: by setting the delay control circuit, there is a corresponding delay in the switching process of the backup power supply, and in the circuit setting, the intermediate relay, the time relay and the relay are set in the middle to control the start of the backup power supply, so that the circuit is reliable. Increased performance and simple structure.

By connecting a normally closed auxiliary contact of the AC contactor KM2 to the coil end of the AC contactor KM1, before the maintenance of the main power supply is determined, even if the main power supply is restored, the power supply cannot be continued, and the overall reliability of the circuit is improved. sex.

At the same time, use the other auxiliary contacts of AC contactor KM2 to control the intermediate relay and time relay at the same time, and use the auxiliary contacts of AC contactor KM2 to perform self-locking, so that only the coil of AC contactor KM2 The line with the auxiliary contact KM2-4 has power, and the other lines have no power, thereby achieving the function of power limitation and reducing line loss.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail:

Fig. 1 is a schematic circuit diagram of Embodiment 1 of automatic switching of standby power supply of the present invention.

Detailed ways

Example 1:

As shown in Figure 1, the utility model is an automatic switching circuit for standby power supply, including a first AC contactor KM1 and a second AC contactor KM2, the first AC contactor includes a main contact KM1-1, the The main contact KM1-1 is connected between the main power supply and the electrical equipment, the second AC contactor includes the main contact KM2-1, and the main contact KM2-1 is connected between the backup power supply and the electrical equipment During the period, the coil end of the first AC contactor KM1 is connected to the main power circuit, and it is characterized in that the switching circuit includes a delay control circuit, and the delay control circuit includes an intermediate relay KA1, a time relay KT1, a relay KA2, The power module and the NOT gate, the first AC contactor includes an auxiliary contact KM1-2, the coil end of the intermediate relay KA1 is connected in series with the auxiliary contact KM1-2 in the backup power circuit, and the relay KA1 includes The first contact KA1-1, and the second contact KA1-2, the first contact KA1-1 and the coil end of the time relay KT1 are connected in series in the standby power circuit, and the second contact KA1-2 is connected to the The input end of the power module is connected in series to the backup power circuit, the output end of the power module is connected to a NOT gate, and the contact KT1-1 of the time relay KT1 is connected in series between the input of the NOT gate and the ground of the power module. The output end of the gate controls the coil end of the relay KA2, and the contact KA2-1 of the relay KA2 is connected in series with the coil end of the second AC contactor KM2 in the standby power circuit.

In this embodiment, the main contact KM1-1, the main contact KM2-1, the first contact KA1-1, the second contact KA1-2, the contact KT1-1, and the contact KA2-1 are in It is a normally open contact under normal conditions, and the auxiliary contact KM1-2 is a normally closed contact under normal conditions. The main power supply and the standby power supply are respectively equipped with leakage circuit breakers and fuses before they are connected. Under normal circumstances, the leakage circuit breakers QS1 and QS2 are closed. The closing of leakage circuit breaker QS1 makes the coil of AC contactor KM1 energized, its main contact KM1-1 is closed, and the main power is sent to user equipment through leakage circuit breaker QS1, fuse FU1 and main contact KM1-1. At the same time, the auxiliary contact KM1-2 of the AC contactor KM1 is disconnected, the coil of the intermediate relay KA1 is not powered, and its second contact KA1-2 is not closed, the primary side of the transformer T of the power module has no power, and the secondary side of the transformer T There is also no voltage, and its subsequent circuits do not work. There is no voltage at the coil end of relay KA2, and its contact KA2-1 does not pull in. The AC contactor KM2 coil cannot be powered, and its main contact KM2-1 does not pull in. The power supply does not deliver power to user equipment.

When the main power supply is cut off due to a fault, the AC contactor KM1 coil loses power, its main contact KM1-1 is disconnected, the main power supply on the grid is disconnected, the user cannot get electricity from the grid, and the grid line is waiting for maintenance. At the same time, due to the de-energization of the coil of the AC contactor KM1, its auxiliary contact KM1-2 is closed, and the one-phase voltage of the backup power supply energizes the coil of the intermediate relay KA1. The energization of the intermediate relay KA1 coil, on the one hand, makes its second contact KA1-2 close, so the primary side of the transformer T is energized, and the AC voltage is sent from the secondary side after the step-down of the transformer T, and then works through the rectifier UR Obtain pulsating direct current, and then through the work of the voltage regulator IC1, a stable +5V direct current voltage is obtained at both ends of the capacitor C2; on the other hand, the first contact KA1-1 is closed, and the coil of the time relay KT1 After being powered on, after a proper delay, its contact KT1-1 is closed, and the input side of the inverter IC2 inputs a low level, then the output side of the inverter IC2 receives a high level, and this high level drives the transistor VT saturation conduction The coil of the relay KA2 is energized, and its contact KA2-1 is closed, and finally the coil of the AC contactor KM2 is energized, the main contact KM2-1 of KM2 is closed, and the backup power supply passes through the leakage circuit breaker QS2, Fuse FU3 and main contact KM2-1 provide voltage to users.

By setting the delay control circuit, there is a corresponding delay in the switching process of the backup power supply, and in the circuit setting, the intermediate relay, the time relay and the relay are set in the middle to control the start of the backup power supply, so that the reliability of the circuit is increased. Simple structure.

In this embodiment, in order to improve reliability, before the maintenance of the main power supply is confirmed, the power supply cannot be continued even if the main power supply is restored. Therefore, the second AC contactor KM2 includes an auxiliary contact KM2-2 , the auxiliary contact KM2-2 is connected in series with the coil end of the first AC contactor KM1, and the auxiliary contact KM2-2 is a normally closed contact under normal conditions.

When the main power supply starts to work normally, according to the above-mentioned principle, the coil of the AC contactor KM2 cannot be energized, so the auxiliary contact KM2-2 is in a closed state, so that the coil of the AC contactor KM1 can be energized normally, thus ensuring the normal power supply of the main power supply . When the main power supply fails, it can be seen from the above principles that the coil end of the AC contactor KM2 is powered, so its auxiliary contact KM2-2 will be in the disconnected state, and at this time the coil of the AC contactor KM1 will be disconnected from the main power circuit. Therefore, before the maintenance is confirmed, even if the main power supply is restored, the backup power supply is still used, which makes the circuit safer.

In this embodiment, the reliability of the circuit can be further increased, and energy consumption has been saved, because when the backup power supply is normally connected to the user equipment, the delay control circuit is no longer required to work, so it needs to be powered off to save energy and reduce consumption. Therefore, in this embodiment, the second AC contactor KM2 includes an auxiliary contact KM2-3, and the auxiliary contact KM2-3 is connected in series with the coil end of the time relay KT1. The second AC contactor KM2 includes an auxiliary contact KM2-4, and the auxiliary contact KM2-4 is connected in parallel with the contact KA2-1 of the relay KA2. The second AC contactor KM2 includes an auxiliary contact KM2-5, and the auxiliary contact KM2-5 is connected in series with the coil end of the intermediate relay KA1. The auxiliary contacts KM2-3 and KM2-5 are normally closed contacts under normal conditions, and the auxiliary contacts KM2-4 are normally open contacts under normal conditions.

The electrification of the coil of the AC contactor KM2 also makes its auxiliary contact KM2-4 closed, and the auxiliary contacts KM2-3 and KM2-5 open. The closing of the auxiliary contact KM2-4 realizes the self-locking function, so that even if the contact KA2-1 is disconnected, the coil of the AC contactor KM2 still has power, and the backup power supply keeps supplying power to the user. The disconnection of the auxiliary contact KM2-3 makes the coil of the time relay KT1 de-energized. In addition, the disconnection of the auxiliary contact KM2-5 makes the coil of the intermediate relay KA1 de-energized, its auxiliary contact KA1-2 is disconnected, the transformer T is de-energized, and the subsequent relay KA2 is also de-energized, and its contact KA2-1 disconnect. Due to the self-locking function of KM2, KM2 still has power. At this time, in the control circuit, only the coil of the AC contactor KM2 and the circuit of the auxiliary contact KM2-4 have power, and the other lines have no power, thereby achieving the function of power limitation and reducing line loss.

By setting the delay control circuit, there is a corresponding delay in the switching process of the backup power supply, and in the circuit setting, the intermediate relay, the time relay and the relay are set in the middle to control the start of the backup power supply, so that the reliability of the circuit is increased. Simple structure.

By connecting a normally closed auxiliary contact of the AC contactor KM2 to the coil end of the AC contactor KM1, before the maintenance of the main power supply is determined, even if the main power supply is restored, the power supply cannot be continued, and the overall reliability of the circuit is improved. sex.

At the same time, use the other auxiliary contacts of AC contactor KM2 to control the intermediate relay and time relay at the same time, and use the auxiliary contacts of AC contactor KM2 to perform self-locking, so that only the coil of AC contactor KM2 The line with the auxiliary contact KM2-4 has power, and the other lines have no power, thereby achieving the function of power limitation and reducing line loss.

It should be emphasized that the protection scope of the present utility model includes but is not limited to the above-mentioned specific embodiments. It should be pointed out that for those skilled in the art, some modifications and improvements can be made without departing from the principle of the utility model, and these should also be regarded as belonging to the protection scope of the utility model.

Claims (8)

1. a stand-by power supply automatic switch-over circuit, comprise the first A.C. contactor KM1 and the second A.C. contactor KM2, described first A.C. contactor includes main contacts KM1-1, described main contacts KM1-1 is connected between main power source and power consumption equipment, described second A.C. contactor includes main contacts KM2-1, described main contacts KM2-1 is connected between stand-by power supply and power consumption equipment, the coil-end of described first A.C. contactor KM1 is connected to main power circuit, it is characterized in that, described commutation circuit comprises delay control circuit, described delay control circuit includes auxiliary relay KA1, time relay KT1, relay K A2, power module and not gate, described first A.C. contactor includes auxiliary contact KM1-2, coil-end and the described auxiliary contact KM1-2 of described auxiliary relay KA1 are connected on stand-by power supply loop, described relay K A1 comprises the first contact KA1-1, with the second contact KA1-2, the coil-end of described first contact KA1-1 and time relay KT1 is connected on stand-by power supply loop, the input of described second contact KA1-2 and described power module is connected on stand-by power supply loop, the output of described power module connects not gate, the contact KT1-1 of described time relay KT1 is connected between not gate input and the ground of power module, the output of described not gate controls the coil-end of described relay K A2, the contact KA2-1 of described relay K A2 and the coil-end of the second A.C. contactor KM2 are connected on stand-by power supply loop.

2. stand-by power supply automatic switch-over circuit according to claim 1, it is characterized in that, described second A.C. contactor KM2 comprises auxiliary contact KM2-2, and described auxiliary contact KM2-2 connects with the coil-end of the first A.C. contactor KM1, and described auxiliary contact KM2-2 is normally-closed contact under normal conditions.

3. stand-by power supply automatic switch-over circuit according to claim 1, is characterized in that, described second A.C. contactor KM2 comprises auxiliary contact KM2-3, and the coil-end of described auxiliary contact KM2-3 and time relay KT1 is connected in series.

4. stand-by power supply automatic switch-over circuit according to claim 3, is characterized in that, described second A.C. contactor KM2 comprises auxiliary contact KM2-4, and the contact KA2-1 of described auxiliary contact KM2-4 and described relay K A2 is connected in parallel.

5. stand-by power supply automatic switch-over circuit according to claim 4, is characterized in that, described second A.C. contactor KM2 comprises auxiliary contact KM2-5, and the coil-end of described auxiliary contact KM2-5 and auxiliary relay KA1 is connected in series.

6. stand-by power supply automatic switch-over circuit according to claim 5, is characterized in that, described auxiliary contact KM2-3, auxiliary contact KM2-5 are normally-closed contact under normal conditions, and described auxiliary contact KM2-4 is normally opened contact under normal conditions.

7. stand-by power supply automatic switch-over circuit according to claim 1, is characterized in that, described power module comprises transformer, regulator rectifier circuit, and described not gate exports and drives relay K A2 by triode.

8. stand-by power supply automatic switch-over circuit according to claim 1, it is characterized in that, described main contacts KM1-1, main contacts KM2-1, the first contact KA1-1, the second contact KA1-2, contact KT1-1, contact KA2-1 are normally opened contact under normal conditions, and described auxiliary contact KM1-2 is normally-closed contact under normal conditions.