Anti-interference-electricity low-voltage electrical circuit

Abstract

The invention relates to the technical field of low-voltage electrical control, and discloses an anti-interference low-voltage electrical circuit which comprises a three-phase power supply, a circuit breaker QF0, a circuit breaker QF1, a circuit breaker QF5, a motor circuit breaker, an alternating current contactor KM1, an auxiliary oil pump motor M1, a change-over switch SA, a stop button SB1, a start button SB2, an intermediate relay KA1, an intermediate relay KA2, an intermediate relay KA3 and a time relay KT. And the time relay KT is used as an anti-interference electricity module, and a power-off delay contact of the time relay KT is connected in series / in parallel with coil control logic of the alternating current contactor KM1 and is used for monitoring voltage, disconnecting the contact according to set delay after power loss and quickly responding when power is on so as to cooperatively realize self-starting. The power-on self-starting function of the motor is realized by utilizing the power-off delay function of the anti-interference electricity module or the time relay, and the power-on self-starting device is suitable for an electrical control loop of important equipment, is simple, reliable and convenient to operate, and greatly improves the power supply reliability of the electrical equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-voltage electrical control, in particular to an anti-flicker low-voltage electrical circuit. BACKGROUND

[0002] In the existing low-voltage electrical control system, for motor-driven equipment, an AC contactor is usually used as a core control element to construct a direct start-up circuit. The coil of the AC contactor is triggered to be powered on by a manual or automatic (such as DCS) signal, thereby controlling the main contact to be closed to realize the start-up operation of the motor and to ensure the equipment to operate under the preset working condition.

[0003] However, flicker faults (such as voltage sag and short-time interruption) occur frequently during the operation of the power system. When the flicker causes the coil voltage of the AC contactor in the control circuit to decrease to the release threshold value of the AC contactor, the moving and static contacts of the AC contactor will be released rapidly, and the motor that is in operation will be automatically tripped and stopped due to the loss of power supply. For Class I electrical equipment, such unplanned shutdown not only directly interrupts the normal production process, but also may cause safety hazards such as damage to key components of the equipment and disorder of the production process, seriously threatening the long-term safe and stable operation of the equipment, and even may cause economic losses.

[0004] The current important low-voltage electrical control circuit generally lacks a targeted flicker protection function. On the one hand, when a flicker fault occurs, the circuit cannot maintain the attraction state of the AC contactor, resulting in the equipment being inevitably stopped; on the other hand, even if the voltage of the power system is restored to normal subsequently, the existing circuit cannot automatically trigger the AC contactor to be attracted again, and the restart of the equipment needs to rely on manual operation. This process not only increases the labor cost, but also prolongs the downtime of the equipment due to the lag of the restart operation, further amplifying the negative impact of the flicker fault on the production operation. Therefore, there is an urgent need for a low-voltage electrical control scheme that can effectively respond to flicker faults and automatically restart the equipment after the voltage is restored, to make up for the defects of the existing technology. SUMMARY

[0005] The present application provides an anti-flicker low-voltage electrical circuit, which uses the power-off delay function of the anti-flicker module or the time relay to realize the self-starting function of the motor, and is suitable for the electrical control circuit of important equipment. It is simple, reliable and easy to operate, and greatly improves the power supply reliability of electrical equipment.

[0006] The present application provides an anti-flicker low-voltage electrical circuit, which includes a three-phase power supply, a circuit breaker QF0, a circuit breaker QF1, a circuit breaker QF5, a motor circuit breaker, an AC contactor KM1, an auxiliary oil pump motor M1, a changeover switch SA, a stop button SB1, a start button SB2, an intermediate relay KA1, an intermediate relay KA2, an intermediate relay KA3, and a time relay KT.

[0007] The three-phase power supply and neutral line N are accessed, the L1, L2, L3 phases of the three-phase power supply are connected to the incoming line end of the circuit breaker QF0, and the outgoing line end of the circuit breaker QF0 is divided into two paths, one of which leads to the main circuit and the other of which leads to the control circuit;

[0008] In the main circuit, the L1, L2, L3 phases of the outgoing line of the circuit breaker QF0 are connected to the incoming line end of the circuit breaker QF1, the outgoing line end of the circuit breaker QF1 is connected to the incoming line end of the motor circuit breaker, the outgoing line end of the motor circuit breaker is connected to the main contact incoming line end of the AC contactor KM1, and the main contact outgoing line end of the AC contactor KM1 is connected to the U1, V1, W1 connection terminals of the auxiliary oil pump motor M1.

[0009] In the control circuit, the L1 phase of the outgoing line of the circuit breaker QF0 is connected to the incoming line end of the circuit breaker QF5, the outgoing line end of the circuit breaker QF5 is connected to the incoming common end of the transfer switch SA, one end of the manual gear movable contact of the transfer switch SA is connected to one end of the coil of the intermediate relay KA1, one end of the DCS gear movable contact of the transfer switch SA is connected to one end of the coil of the intermediate relay KA2, and the other ends of the intermediate relays KA1 and KA2 are both connected to the neutral line N.

[0010] The power supply end of the control circuit is connected to one end of the DCS stop contact, the other end of the DCS stop contact is connected to one end of the stop button SB1, the other end of the stop button SB1 is connected to one end of the intermediate relay KA2 contact 1-6, the other end of the intermediate relay KA2 contact 1-6 is connected to node 1-2, node 1-2 is simultaneously connected to one end of the start button SB2 and one end of the intermediate relay KA1 contact 1-3, the other end of the start button SB2 is connected to node 1-4, the other end of the intermediate relay KA1 contact 1-3 is connected to one end of the auxiliary contact of the AC contactor KM1, the other end of the auxiliary contact of the AC contactor KM1 is connected to one end of the coil of the time relay KT, the other end of the coil of the time relay KT is connected to the common end of the circuit, one end of the time relay KT delay contact is connected to the DCS start end, the other end of the time relay KT delay contact is connected to one end of the coil of the AC contactor KM1, one end of the coil of the AC contactor KM1 is connected to one end of the contact of the intermediate relay KA3, and the other end of the contact of the intermediate relay KA3 is connected to the neutral line N.

[0011] Further, the time relay KT serves as an anti-bang module, and its power-off delay contact is connected in series / parallel to the control logic of the coil of the AC contactor KM1, is used to monitor the voltage, and is disconnected after power loss for a set delay, and quickly responds when power is restored, so as to realize self-starting.

[0012] Further, the circuit breaker QF0 is used for main circuit power supply total protection, cutting off L1, L2, L3 three power supplies in overload and short circuit, the circuit breaker QF1 is used for protecting the power supply into the motor circuit breaker circuit, and the circuit breaker QF5 is used for providing overload and short circuit protection for the control circuit L1 phase.

[0013] Further, in the manual mode, the normal starting process is as follows:

[0014] When the change-over switch SA is switched to the manual gear, the current output by the control circuit power supply end reaches the node 1-2 through the DCS stop contact, the stop button SB1 and the intermediate relay KA2 contact 1-6; the operator presses the start button SB2, the current at the node 1-2 flows to the node 1-4 through the start button SB2, and then is divided into two paths, one path triggers the intermediate relay KA1 coil to be powered, and the intermediate relay KA1 coil is powered, and its contact 1-3 is immediately closed after the intermediate relay KA1 coil is powered, to realize self-locking; the other path of the current flows to the 25th end of the time relay KT coil through the intermediate relay KA1 contact 1-3 and the auxiliary contact of the AC contactor KM1, the time relay KT coil is powered after being powered, and starts to delay according to the preset time, and the time relay KT delay contact is closed after the delay is completed; the current flows to the coil 1-4 of the AC contactor KM1 through the closed KT delay contact and the DCS start end, and then flows back to the circuit common end through the coil 1-5 end of the AC contactor KM1 and the contact of the intermediate relay KA3, and the coil of the AC contactor KM1 is powered; the main contact of the AC contactor KM1 is closed, and the three-phase power supply is transmitted to the auxiliary oil pump motor M1 through the circuit breakers QF0, QF1, the motor circuit breaker and the main contact of the AC contactor KM1, and the auxiliary oil pump motor M1 starts to operate;

[0015] The normal stopping process is as follows:

[0016] If the auxiliary oil pump motor M1 needs to be manually stopped, the operator presses the stop button SB1, and after the stop button SB1 is disconnected, the path from the DCS stop contact to the intermediate relay KA2 contact 1-6 in the control circuit is cut off, the intermediate relay KA1 coil loses power, the contact 1-3 thereof resets and is disconnected, and the self-locking circuit is disabled; the time relay KT coil loses power, the delay contact thereof resets and is disconnected, the coil of the AC contactor KM1 loses current supply, the main contact thereof is disconnected after the coil loses power, the auxiliary oil pump motor M1 loses the three-phase power supply, and stops operating.

[0017] Further, in the manual mode, the power swing response process is as follows:

[0018] When the voltage fluctuation occurs, the control circuit voltage instantaneously decreases, the intermediate relay KA1 coil and the time relay KT coil are temporarily de-energized, but the anti-voltage fluctuation module connected in parallel across the AC contactor KM1 coil immediately starts the power-off delay function, and its auxiliary contact remains closed to maintain the power supply loop of the AC contactor KM1 coil; at the same time, the auxiliary contact of the anti-voltage fluctuation module is connected in the self-locking loop of the AC contactor KM1, which also remains closed to avoid the disconnection of the self-locking loop; if the voltage recovers to normal within the set delay time of the anti-voltage fluctuation module, the control circuit voltage rises to the normal attraction voltage value of the AC contactor KM1 coil, the auxiliary contact of the anti-voltage fluctuation module remains closed, the AC contactor KM1 coil continues to be energized, and the main contact remains closed, so the auxiliary oil pump motor M1 does not need to restart and continues to operate stably; if the voltage interruption lasts beyond the delay time, the auxiliary contact of the anti-voltage fluctuation module opens, the AC contactor KM1 coil loses power, the main contact opens, and the auxiliary oil pump motor M1 stops; when the subsequent voltage recovers to normal, the auxiliary contact of the anti-voltage fluctuation module re-closes, the control circuit is connected through node 1-2, KA1 contact 1-3 or start button SB2, the KM1 coil is energized again, the main contact is closed, and the auxiliary oil pump motor M1 is automatically started.

[0019] Further, in the DCS automatic mode, the normal starting process is as follows:

[0020] After the changeover switch SA is switched to the DCS gear, the DCS system sends a DCS start signal, the DCS start terminal in the control circuit is connected, and the current flows back to the common terminal through the DCS start terminal, the time relay KT delay contact, the AC contactor KM1 coil 1-4 terminal, the AC contactor KM1 coil 1-5 terminal, and the intermediate relay KA3 contact, but at this time the time relay KT delay contact is not closed, and the loop is not connected; at the same time, the DCS start signal triggers another current through the related circuit to energize the time relay KT coil No. 25, and the time relay KT starts to delay; after the delay is over, the time relay KT delay contact is closed, the above-mentioned loop through the DCS start terminal is completely connected, the AC contactor KM1 coil is energized, the main contact is closed, and the auxiliary oil pump motor M1 starts to operate; during this period, the AC contactor KM1 auxiliary contact is closed with the coil energized, and if subsequent voltage fluctuation occurs, the auxiliary maintenance loop is stable;

[0021] The normal stopping process is as follows:

[0022] The DCS system sends a DCS stop signal, the DCS stop contact in the control circuit is disconnected, the current cannot pass through the DCS stop contact, the stop button SB1 and the intermediate relay KA2 contact 1-6 to reach the node 1-2, the intermediate relay KA1 and the time relay KT coil lose power, the time relay KT delay contact resets and is disconnected, the AC contactor KM1 coil loses power, the main contact is disconnected, and the auxiliary oil pump motor M1 stops running; if emergency stop is required, the operator presses the stop button SB1 to cut off the control circuit, and the auxiliary oil pump motor M1 is stopped.

[0023] Further, in the DCS automatic mode, the power swing response process is as follows:

[0024] When the power swing occurs, the anti-power swing module starts the power-off delay function, the auxiliary contact in parallel between the AC contactor KM1 coil and the auxiliary contact in the self-locking loop remain closed, maintaining the power supply of the AC contactor KM1 coil or the self-locking loop; after the voltage returns to normal, if the DCS does not send a stop signal, the DCS stop contact remains closed, the control circuit is automatically connected through the anti-power swing module auxiliary contact, the AC contactor KM1 coil is powered, the main contact is closed, the auxiliary oil pump motor M1 continues to run or automatically restarts, and the normal operation of the equipment is ensured.

[0025] The beneficial effects of the present application are as follows:

[0026] The present application configures an anti-power swing module or a time relay in the original low-voltage electrical control circuit, uses the power-off delay function to effectively solve the problem of unplanned motor shutdown and inability to automatically restart caused by power swing failure in the prior art, compared with the original control circuit, only the configuration of the anti-power swing module or the time relay needs to be added, without the need for large-scale modification of the original circuit, and the one-time investment can realize the power-on self-starting function of the motor. When the power swing failure occurs, the anti-power swing module or the time relay can maintain the short circuit of the AC contactor coil power supply circuit or the self-locking circuit, avoid the false release of the AC contactor due to voltage sag, automatically trigger the AC contactor coil to re-attract after the system voltage returns to normal, drive the motor to restart, and ensure the stable operation of the important load such as the class I electrical equipment, greatly improve the power supply reliability of the electrical equipment; not only can be applied to the electrical control circuit of the driving auxiliary oil pump and other specific important equipment, but also can be adapted to all low-voltage electrical control circuit scenes, effectively reducing the labor restart cost, shortening the downtime of the equipment due to power swing, reducing the production loss and equipment damage risk caused by downtime, and providing a powerful guarantee for the safe and stable operation of the low-voltage electrical equipment. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The circuit principle diagram of the anti-power swing low-voltage electrical circuit of the present application.

[0028] The objectives, functional features and advantages of the present application will be further illustrated in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

[0030] The present application utilizes the power-off delay function of the anti-flicker module or time relay to realize the power-on self-starting function of the motor, is suitable for the electrical control circuit of important equipment, has one-time investment, is convenient to install, has a simple and reliable system, is convenient to operate, has wide applicability, and greatly improves the power supply reliability of the electrical equipment.

[0031] As shown in Figure 1 The present application provides an anti-flicker low-voltage electrical circuit, comprising a three-phase power supply, a circuit breaker QF0, a circuit breaker QF1, a circuit breaker QF5, a motor circuit breaker, an alternating current contactor KM1, an auxiliary oil pump motor M1, a change-over switch SA, a stop button SB1, a start button SB2, intermediate relays KA1, KA2 and KA3, and a time relay KT; the time relay KT is used as an anti-flicker module, and its power-off delay contact point is connected in series / parallel to the coil control logic of the alternating current contactor KM1, is used for monitoring the voltage, and is disconnected according to the set delay time after power failure, and quickly responds when power is on, so as to realize self-starting.

[0032] The connection relationship is as follows:

[0033] The three-phase power supply and the neutral line N are connected, the circuit breaker QF0 (IC65N 30P 25A) is used as the total power supply protection, the L1, L2 and L3 phases of the three-phase power supply are connected to the incoming line end of the circuit breaker QF0, and the outgoing line end of the circuit breaker QF0 is divided into two paths, one of which leads to the main circuit, and the other of which leads to the control circuit.

[0034] (1) Main circuit

[0035] In the main circuit, the L1, L2 and L3 phases of the outgoing line of the circuit breaker QF0 are connected to the incoming line end of the circuit breaker QF1 (IC65N type), the outgoing line end of the circuit breaker QF1 is connected to the incoming line end of the motor circuit breaker GV2PM14C, and overload and short-circuit protection is implemented on the power supply entering the main circuit of the auxiliary oil pump motor M1.

[0036] The outgoing line end of the motor circuit breaker GV2PM14C is connected to the main contact incoming line end of the alternating current contactor KM1 (LC1D18M7C), and the electrical safety of the auxiliary oil pump motor M1 circuit is further ensured.

[0037] The main contact outlet end of the AC contactor KM1 is connected to the U1, V1 and W1 terminals of the auxiliary oil pump motor M1 (4KW 8.7A), and controls the on-off of the three-phase power supply of the auxiliary oil pump motor M1. The neutral line of the auxiliary oil pump motor M1 is connected in a normal manner through the main circuit related grounding or the like.

[0038] (2) Control circuit

[0039] ① Mode switching

[0040] In the control circuit, the L1 phase of the outlet of the circuit breaker QF0 is connected to the inlet end of the circuit breaker QF5 (IC65N 1P C6), and the outlet end of the circuit breaker QF5 is connected to the inlet common end of the change-over switch SA, thereby providing the power supply after overload and short-circuit protection for the L1 phase of the control circuit.

[0041] The change-over switch SA is a three-position (manual, stop, DCS) change-over switch, and the three stationary contacts thereof correspond to the manual, stop and DCS functions respectively. The manual position movable contact of the change-over switch SA is connected to one end of the coil of the intermediate relay KA1, the DCS position movable contact of the change-over switch SA is connected to one end of the coil of the intermediate relay KA2, and the other ends of the intermediate relays KA1 and KA2 are both connected to the neutral line N, thereby forming part of the coil power supply circuit.

[0042] ② Start-stop logic

[0043] The control circuit power supply end is connected to one end of the DCS stop contact, and the other end of the DCS stop contact is connected to one end of the stop button SB1. The other end of the stop button SB1 is connected to one end of the intermediate relay KA2 contact 1-6, and the other end of the intermediate relay KA2 contact 1-6 is connected to node 1-2. The node 1-2 is simultaneously connected to one end of the start button SB2 and one end of the intermediate relay KA1 contact 1-3, and the other end of the start button SB2 is connected to node 1-4. The other end of the intermediate relay KA1 contact 1-3 is connected to one end of the auxiliary contact (two groups in parallel) of the AC contactor KM1, and the other end of the auxiliary contact of the AC contactor KM1 is connected to one end of the coil of the time relay KT (No. 25 terminal). The other end of the coil of the time relay KT (No. 28 terminal) is connected to the circuit common end. One end of the time relay KT delay contact is connected to the DCS start end, and the other end of the time relay KT delay contact is connected to one end of the coil of the AC contactor KM1 (1-4 terminal). The other end of the coil of the AC contactor KM1 (1-5 terminal) is connected to one end of the contact of the intermediate relay KA3, and the other end of the contact of the intermediate relay KA3 is connected to the neutral line N.

[0044] The stop button SB1 is a normally closed button, and when SB1 is pressed, the control circuit power is cut off, and the auxiliary oil pump motor M1 is stopped. The start button SB2 is a normally open button, and the middle relay KA1 contact 1-3 is a normally open contact, which is connected in parallel with the start button SB2 to realize self-locking: after the start button SB2 is pressed, the middle relay KA1 coil is powered, the middle relay KA1 contact 1-3 is closed, and after SB2 is released, the middle relay KA1 coil is still powered. The time relay KT delay contact operates with a set time delay, the AC contactor KM1 main contact controls the main circuit auxiliary oil pump motor M1 power, and the auxiliary contact 1-5 participates in the control circuit self-locking and logic interlocking. The middle relay KA2 contact 1-6 participates in the DCS stop signal logic, and when the DCS sends a stop command, it cooperates with SB1 to cut off the circuit. The middle relay KA3 contact 1-5 is controlled by the DCS start signal, and when the DCS sends a start command, the KA3 coil is powered, and the contact 1-5 is closed. The circuit breaker QF0 is used for total protection of the main circuit power, and cuts off L1, L2 and L3 power when overloaded or short-circuited, the circuit breaker QF1 is used for protecting the power entering the motor circuit breaker circuit, and the circuit breaker QF5 is used for providing overload and short-circuit protection for the control circuit L1 phase.

[0045] The workflow of the present application is as follows:

[0046] (1) Manual mode

[0047] ① Normal start

[0048] When the switch SA is switched to the manual position, the current output from the control circuit power supply end flows through the DCS stop contact (the DCS does not send a stop signal at this time, and the contact remains closed), the stop button SB1 (which is in a closed state when not pressed), the intermediate relay KA2 contact 1-6 (which is in a closed state when not actuated) to node 1-2; the operator presses the start button SB2, and the current at node 1-2 flows to node 1-4 through SB2, and then is divided into two paths, one of which triggers the intermediate relay KA1 coil to be powered on, and after the KA1 coil is powered on, its contact 1-3 is immediately closed to achieve self-locking (at this time, SB1 is released, and the current can continue to flow from node 1-2 to node 1-4 through the KA1 contact 1-3); the other path of the current flows through the KA1 contact 1-3, the auxiliary contact of the AC contactor KM1 (the auxiliary contact is initially closed because KM1 has not been actuated), and the 25th end of the time relay KT coil, and after the KT coil is powered on, it starts to delay for a preset time, and after the delay ends, the KT delay contact is closed; the current flows through the closed KT delay contact, the DCS start end (the DCS start end has no signal in the manual mode, which does not affect the path), to the KM1 coil 1-4 end of the AC contactor, and then flows back to the loop common end through the KM1 coil 1-5 end and the intermediate relay KA3 contact (which remains closed in the manual mode), and the KM1 coil is powered on; the main contact of KM1 is closed, and the three-phase power supply is transmitted to the auxiliary oil pump motor M1 through the circuit breakers QF0, QF1, the motor circuit breaker GV2PM14C, and the main contact of KM1, and the auxiliary oil pump motor M1 starts to operate.

[0049] ②Normal stop

[0050] If it is necessary to manually stop the auxiliary oil pump motor M1, the operator presses the stop button SB1, and after SB1 is disconnected, the path from the DCS stop contact to the intermediate relay KA2 contact 1-6 in the control circuit is cut off, the intermediate relay KA1 coil loses power, its contact 1-3 resets and opens, and the self-locking circuit fails; the time relay KT coil loses power, its delay contact resets and opens, the AC contactor KM1 coil loses current supply, the main contact opens after the coil loses power, the auxiliary oil pump motor M1 loses three-phase power supply, and stops operating.

[0051] ③Power swing response

[0052] When the system appears to sway electricity (voltage sag or short interruption), the control loop voltage momentary decrease, intermediate relay KA1 coil, time relay KT coil may be short power failure, but parallel in the KM1 coil both ends of the anti-swing module (or power failure delay time relay) immediately start power failure delay function, its auxiliary contact remains closed, maintain KM1 coil power supply loop access; At the same time, the auxiliary contact of the anti-swing module is connected in the KM1 self-locking loop, which is also closed to avoid the disconnection of the self-locking loop. If the voltage recovers to normal within the delay time set by the anti-swing module, the control loop voltage rises to the normal pull-in voltage value of the KM1 coil, the anti-swing module auxiliary contact remains closed, the KM1 coil continues to be powered, and the main contact remains closed. The auxiliary oil pump motor M1 does not need to restart and continues to operate stably; If the voltage continues to interrupt for more than the delay time, the anti-swing module auxiliary contact opens, the KM1 coil loses power, the main contact opens, and the auxiliary oil pump motor M1 stops; When the voltage recovers to normal, the anti-swing module auxiliary contact re-closes, the control loop is connected through node 1-2, KA1 contact 1-3 (if KA1 has not completely lost power self-locking before) or SB2 (which needs to be pressed again), the KM1 coil is powered again, the main contact is closed, and the auxiliary oil pump motor M1 is automatically started.

[0053] (2) DCS automatic mode

[0054] ① Normal start

[0055] After the switch SA is switched to the DCS gear, the DCS system sends a DCS start signal, the DCS start terminal in the control loop is connected, and the current flows back to the common terminal through the DCS start terminal, the time relay KT delay contact (initially inactive, in the open state, KT coil needs to be powered first), KM1 coil 1-4 terminal, KM1 coil 1-5 terminal, and intermediate relay KA3 contact (DCS start signal also triggers KA3 coil power, its contact is closed). However, at this time, the KT delay contact is not closed, and the loop is not connected. At the same time, the DCS start signal triggers another current through the related circuit (parallel to node 1-2 in manual mode) to power the time relay KT coil 25 terminal, and KT starts to delay. After the delay is over, the KT delay contact is closed, the above-mentioned loop through the DCS start terminal is completely connected, the KM1 coil is powered, the main contact is closed, and the auxiliary oil pump motor M1 starts to operate. During this period, the KM1 auxiliary contact is closed with the coil power, which can assist in maintaining the stability of the loop if a short voltage fluctuation occurs later.

[0056] ② Normal stop

[0057] The DCS system sends a DCS stop signal, the DCS stop contact in the control circuit is disconnected, the current cannot pass through the DCS stop contact, SB1, KA2 contact 1-6 to node 1-2, the intermediate relay KA1 (if associated), the time relay KT coil loses power, the KT delay contact resets and disconnects, the KM1 coil loses power, the main contact disconnects, and the auxiliary oil pump motor M1 stops running; if emergency stop is required, the operator presses the stop button SB1, and the control circuit can also be cut off to stop the auxiliary oil pump motor M1.

[0058] ③Sway power response

[0059] The anti-sway power module is started when the sway power occurs, and the auxiliary contacts in parallel between the KM1 coil and the auxiliary contacts in the self-locking circuit remain closed, maintaining the KM1 coil power supply or the self-locking circuit; after the voltage returns to normal, if the DCS does not send a stop signal, the DCS stop contact remains closed, the control circuit is automatically connected through the anti-sway power module auxiliary contact, the KM1 coil is powered, the main contact is closed, the auxiliary oil pump motor M1 continues to run or automatically restarts, and the normal operation of the equipment is ensured.

[0060] In the original electrical control circuit, the coils of the AC contactor are connected in parallel with the anti-sway power module (or power-off delay time relay) at both ends, to achieve the function of monitoring the system voltage in the running condition; in the original electrical control circuit, the anti-sway power module or time relay (power-off delay) auxiliary contact is connected in parallel in the self-locking circuit of the AC contactor, and when the anti-sway power module (or power-off delay time relay) loses power, the contact remains closed; when the system voltage returns to normal, the control circuit is automatically connected when the normal pull-in voltage value of the AC contactor coil is reached, the motor is automatically started, and the normal operation of the driven equipment is ensured; the anti-sway power module or time relay (power-off delay) installed should be set to the power-off delay time in time, which can ensure the delay release time after the anti-sway power module or time relay loses power.

[0061] Compared with the original control circuit, the anti-sway power module or time relay can realize the power-on self-starting function of the motor, ensure the stable operation of some important loads, greatly improve the reliability of power supply, and has a wide range of applications, and is suitable for all low-voltage electrical control circuits.

[0062] It is to be understood that the terminology "including", "comprising", or any other variation thereof, is intended to cover a non-exclusive inclusion such that process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0063] The above description is merely the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made according to the content of the present application specification and drawings, or directly or indirectly applied to other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An anti-flicker low voltage electrical circuit, characterized in that, Three-phase power supply, circuit breaker QF0, circuit breaker QF1, circuit breaker QF5, motor circuit breaker, AC contactor KM1, auxiliary oil pump motor M1, change-over switch SA, stop button SB1, start button SB2, intermediate relay KA1, intermediate relay KA2, intermediate relay KA3, time relay KT; The three-phase power supply and neutral line N are connected, the L1, L2 and L3 phases of the three-phase power supply are connected to the incoming line end of the circuit breaker QF0, and the outgoing line end of the circuit breaker QF0 is divided into two paths, one of which leads to the main circuit and the other of which leads to the control circuit; In the main circuit, the L1, L2 and L3 phases of the outgoing line end of the circuit breaker QF0 are connected to the incoming line end of the circuit breaker QF1, the outgoing line end of the circuit breaker QF1 is connected to the incoming line end of the motor circuit breaker, the outgoing line end of the motor circuit breaker is connected to the main contact incoming line end of the AC contactor KM1, and the main contact outgoing line end of the AC contactor KM1 is connected to the U1, V1 and W1 connection ends of the auxiliary oil pump motor M1; In the control circuit, the L1 phase of the outgoing line end of the circuit breaker QF0 is connected to the incoming line end of the circuit breaker QF5, the outgoing line end of the circuit breaker QF5 is connected to the incoming common end of the change-over switch SA, one end of the coil of the intermediate relay KA1 is connected to the manual gear movable contact of the change-over switch SA, one end of the coil of the intermediate relay KA2 is connected to the DCS gear movable contact of the change-over switch SA, and the other ends of the intermediate relay KA1 and the intermediate relay KA2 are both connected to the neutral line N; The power supply end of the control circuit is connected to one end of the DCS stop contact, the other end of the DCS stop contact is connected to one end of the stop button SB1, the other end of the stop button SB1 is connected to one end of the intermediate relay KA2 contact 1-6, the other end of the intermediate relay KA2 contact 1-6 is connected to node 1-2, node 1-2 is simultaneously connected to one end of the start button SB2 and one end of the intermediate relay KA1 contact 1-3, the other end of the start button SB2 is connected to node 1-4, the other end of the intermediate relay KA1 contact 1-3 is connected to one end of the auxiliary contact of the AC contactor KM1, the other end of the auxiliary contact of the AC contactor KM1 is connected to one end of the coil of the time relay KT, the other end of the coil of the time relay KT is connected to the common end of the circuit, one end of the time relay KT delay contact is connected to the DCS start end, the other end of the time relay KT delay contact is connected to one end of the coil of the AC contactor KM1, one end of the coil of the AC contactor KM1 is connected to the contact of the intermediate relay KA3, and the other end of the contact of the intermediate relay KA3 is connected to the neutral line N.

2. The anti-flicker low voltage electrical circuit according to claim 1, characterized in that, The time relay KT serves as an anti-bang module, and its power-off delay contact is connected in series / parallel to the coil control logic of the AC contactor KM1, is used for monitoring voltage, and is disconnected after power loss for a set delay, and quickly responds when power is restored, so as to realize self-starting.

3. The low voltage electrical circuit according to claim 1, wherein, The circuit breaker QF0 is used for main circuit power supply total protection, cutting off L1, L2, L3 three power supplies in overload and short circuit, the circuit breaker QF1 is used for protecting the power supply into the motor circuit breaker circuit, the circuit breaker QF5 is used for providing overload and short circuit protection for the control circuit L1 phase.

4. The low voltage electrical circuit according to claim 2, wherein, In the manual mode, the normal starting process is as follows: When the change-over switch SA is switched to the manual gear, the current output by the control circuit power supply end reaches node 1-2 through the DCS stop contact, the stop button SB1 and the intermediate relay KA2 contact 1-6; the operator presses the start button SB2, the current at node 1-2 flows to node 1-4 through the start button SB2, and then is divided into two paths, one path triggers the intermediate relay KA1 coil to be powered on, and the intermediate relay KA1 coil is powered on, and its contact 1-3 is closed immediately to realize self-locking; the other path of current flows to the 25th end of the time relay KT coil through the intermediate relay KA1 contact 1-3 and the auxiliary contact of the AC contactor KM1, and the time relay KT coil is powered on to start the preset time delay, and when the delay is over, the time relay KT delay contact is closed; the current flows to the coil 1-4 of the AC contactor KM1 through the closed KT delay contact and the DCS start end, and then flows back to the circuit common end through the coil 1-5 end of the AC contactor KM1 and the contact of the intermediate relay KA3, and the coil of the AC contactor KM1 is powered on; the main contact of the AC contactor KM1 is closed, and the three-phase power supply is transmitted to the auxiliary oil pump motor M1 through the circuit breakers QF0, QF1, the motor circuit breaker and the main contact of the AC contactor KM1, and the auxiliary oil pump motor M1 starts to run; The normal stopping process is as follows: If the auxiliary oil pump motor M1 needs to be manually stopped, the operator presses the stop button SB1, and after the stop button SB1 is disconnected, the path from the DCS stop contact to the intermediate relay KA2 contact 1-6 in the control circuit is cut off, the intermediate relay KA1 coil loses power, its contact 1-3 resets and is disconnected, and the self-locking circuit is invalid; the time relay KT coil loses power, its delay contact resets and is disconnected, the coil of the AC contactor KM1 loses current supply, the main contact is disconnected after the coil loses power, the auxiliary oil pump motor M1 loses the three-phase power supply, and stops running.

5. The anti-flicker low voltage electrical circuit according to claim 4, characterized in that, In the manual mode, the power swing response process is as follows: When the voltage fluctuation occurs, the control circuit voltage instantaneously decreases, the intermediate relay KA1 coil and the time relay KT coil are temporarily de-energized, but the anti-voltage fluctuation module connected in parallel across the AC contactor KM1 coil immediately starts the power-off delay function, the auxiliary contact thereof remains closed, maintaining the power supply loop of the AC contactor KM1 coil; at the same time, the auxiliary contact of the anti-voltage fluctuation module is connected in the self-locking loop of the AC contactor KM1, which also remains closed to avoid the self-locking loop from being disconnected; if the voltage recovers to normal within the set delay time of the anti-voltage fluctuation module, the control circuit voltage rises to the normal attraction voltage value of the AC contactor KM1 coil, the auxiliary contact of the anti-voltage fluctuation module remains closed, the AC contactor KM1 coil continues to be energized, and the main contact remains closed, so the auxiliary oil pump motor M1 does not need to be restarted and continues to operate stably; if the voltage interruption lasts beyond the delay time, the auxiliary contact of the anti-voltage fluctuation module is opened, the AC contactor KM1 coil is de-energized, the main contact is opened, and the auxiliary oil pump motor M1 stops; when the subsequent voltage recovers to normal, the auxiliary contact of the anti-voltage fluctuation module is closed again, the control circuit is connected through the node 1-2, the KA1 contact 1-3 or the start button SB2, the KM1 coil is energized again, the main contact is closed, and the auxiliary oil pump motor M1 is automatically started.

6. The anti-flicker low voltage electrical circuit according to claim 2, characterized in that, In the DCS automatic mode, the normal starting process is as follows: After the switch SA is switched to the DCS gear, the DCS system sends a DCS start signal, the DCS start terminal in the control circuit is connected, the current flows back to the common terminal through the DCS start terminal, the time relay KT delay contact, the AC contactor KM1 coil 1-4 terminal, the AC contactor KM1 coil 1-5 terminal, and the intermediate relay KA3 contact, but at this time the time relay KT delay contact is not closed, and the loop is not connected; at the same time, the DCS start signal triggers another current through the related circuit to energize the time relay KT coil No. 25, and the time relay KT starts to delay; after the delay is over, the time relay KT delay contact is closed, the above-mentioned loop connected through the DCS start terminal is completely connected, the AC contactor KM1 coil is energized, the main contact is closed, and the auxiliary oil pump motor M1 starts to operate; during this period, the AC contactor KM1 auxiliary contact is closed with the coil energized, and if subsequent voltage fluctuation occurs, the auxiliary maintenance loop is stable; The normal stopping process is as follows: The DCS system sends a DCS stop signal, the DCS stop contact in the control circuit is disconnected, the current cannot pass through the DCS stop contact, the stop button SB1, and the intermediate relay KA2 contact 1-6 to reach the node 1-2, the intermediate relay KA1 and the time relay KT coil are de-energized, the time relay KT delay contact is reset and opened, the AC contactor KM1 coil is de-energized, the main contact is opened, and the auxiliary oil pump motor M1 stops operating; if emergency stop is needed, the operator presses the stop button SB1 to cut off the control circuit, and the auxiliary oil pump motor M1 is stopped.

7. The anti-flicker low voltage electrical circuit according to claim 6, characterized in that, In the DCS automatic mode, the voltage fluctuation response process is as follows: When the power fluctuation occurs, the anti-power fluctuation module starts the power-off delay function, the auxiliary contact in parallel between the two ends of the AC contactor KM1 coil and the auxiliary contact in the self-locking loop remain closed, maintaining the power supply of the AC contactor KM1 coil or the self-locking loop; after the voltage returns to normal, if the DCS does not send a stop signal, the DCS stop contact remains closed, the control circuit is automatically connected through the auxiliary contact of the anti-power fluctuation module, the AC contactor KM1 coil is powered on, the main contact is closed, and the auxiliary oil pump motor M1 continues to operate or automatically restarts, ensuring the normal operation of the equipment.

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