CN209896682U - Low-voltage feed switch - Google Patents

Abstract

The low-voltage feed switch is formed from three portions of main circuit, control circuit and protection circuit, and is characterized by that two ends of under-voltage coil in the control circuit are parallelly-connected with a capacitor, the positive pole of the capacitor is connected with positive pole of under-voltage coil circuit, and the negative pole of the capacitor is connected with negative pole of under-voltage coil circuit. The design is simple and ingenious, and the serious consequences caused by low-voltage power failure due to high-voltage reclosing can be effectively avoided; the reliability of power supply is ensured, if the voltage of the power grid disappears momentarily, the low-voltage feed switch breaker cannot break the brake to interrupt the power supply to the next stage, and the reliability of the power supply is ensured; the power supply safety is ensured, when the voltage of a power grid disappears for a long time, the energy of the capacitor can be naturally exhausted, so that the low-voltage feed switch is tripped separately, the starter with the voltage loss function at the subordinate stage is prevented from being started automatically, various hazards caused by the starter are prevented, and the power utilization safety is guaranteed.

Description

Low-voltage feed switch

Technical Field

The utility model relates to a colliery is low pressure flame-proof type feed switch in pit.

Background

The low-voltage feed switch is used as a main switch for low-voltage local power supply control, plays the roles of connecting a power supply and controlling a load downwards, is mainly used for controlling a lower-level power supply, is convenient for the work of overhauling, installing and the like of the lower-level power supply, and can quickly cut off a fault part once the lower-level load fails, and other fault-free parts can normally operate to reduce the fault influence range.

In order to ensure the power supply reliability of a first-stage power load, the high-voltage power supply feed-out switch is provided with an automatic reclosing function, namely, when a line has a temporary fault, the feed-out switch can be automatically switched on again, operation practice proves and related data show that the success rate of the high-voltage reclosing is generally 70-90%, the automatic reclosing can improve the reliability of a power supply line to a certain extent under high voltage, the low-voltage power supply is not meant to have the same reliability, and the importance of the low-voltage reclosing is not considered at the beginning of the design, so that the current low voltage is difficult to realize the same function as the high voltage. The working principle and practice comprehensively prove that the low-voltage power supply output switch loses power immediately after high-voltage power loss, and the high-voltage power supply output switch cannot be used for even instant recovery, and is mainly based on the following reasons: under normal conditions, a feed under-voltage coil needs to be in a long-term power-on state, the under-voltage coil after power-on is affected by magnetic force, an armature pulls a half shaft to rotate for a certain angle to prepare for maintaining attraction of a closing mechanism, when closing of a feed switch is finished, the closing mechanism drives a connecting rod to deflect, the connecting rod is just clamped on the half shaft, the function of mechanical maintenance is realized, once the under-voltage coil loses power and moves, the under-voltage coil deflects and returns after power loss, the half shaft cannot clamp the connecting rod of the closing mechanism, the switch immediately releases brake, a main power supply loop is disconnected with a power grid, power supply is stopped, the main reason that low-voltage instantaneous power loss is caused by instantaneous power failure of a high-voltage power grid and rapid recovery cannot be realized is how to continue to maintain power supply for the under-voltage coil to.

Disclosure of Invention

The utility model aims at designing a low pressure feed switch, this kind of switch can make the undervoltage coil can maintain the power supply when the high voltage electric network cuts off the power supply in the twinkling of an eye, solves the high voltage electric network and cuts off the power supply in the twinkling of an eye and causes the low pressure to lose the power in the twinkling of an eye and can not the problem of quick recovery.

Realize the utility model discloses the technical scheme that the purpose was taken is: the low-voltage feed switch is composed of three major parts, namely a main loop, a control loop and a protection loop, and is characterized in that two ends of an under-voltage coil in the control loop are connected with a capacitor in parallel, the positive pole of the capacitor is connected with the positive pole of the under-voltage coil circuit, and the negative pole of the capacitor is connected with the negative pole of the under-voltage coil circuit.

The utility model has the advantages that: the design is simple and ingenious, and the serious consequences caused by low-voltage power failure due to high-voltage reclosing can be effectively avoided; the reliability of power supply is ensured, if the voltage of the power grid disappears momentarily, the low-voltage feed switch breaker cannot break the brake to interrupt the power supply to the next stage, and the reliability of the power supply is ensured; the power supply safety is ensured, when the voltage of a power grid disappears for a long time, the energy of the capacitor can be naturally exhausted, so that the low-voltage feed switch is tripped separately, the starter with the voltage loss function at the subordinate stage is prevented from being started automatically, various hazards caused by the starter are prevented, and the power utilization safety is guaranteed.

Drawings

Fig. 1 is an electrical schematic diagram of the present invention.

Detailed Description

The utility model discloses a low pressure feed switch comprises major loop, control circuit and three major parts in protection circuit, and its key lies in, a condenser C of undervoltage coil Q both ends parallel connection in control circuit, and the capacity selection requires that the holding time will be greater than the auto-reclosing time for good, generally selects capacity 4700uF, discharge time 2200ms, and condenser C's positive pole is connected with the positive pole of undervoltage coil Q circuit, and condenser C's negative pole is connected with the negative pole of undervoltage coil Q circuit.

The working principle is as follows:

the charging and discharging characteristics of the capacitor are mainly utilized, and when the power supply is normally supplied, the power supply is used for charging the capacitor C and providing power for the under-voltage coil Q. Once the power grid loses power, the control power supply of the low-voltage feed switch disappears immediately, at the moment, the capacitor C releases energy to the under-voltage coil Q immediately, so that the under-voltage coil Q maintains the original power-on state, the under-voltage coil Q can avoid high-voltage reclosing time, and the fact that the low-voltage power loss cannot be maintained due to the fact that a superior power supply disappears instantly is avoided. If the high-voltage power supply loses power for a long time, the energy of the capacitor C only cannot enter the capacitor C, the energy is slowly exhausted along with the time, after the energy is completely lost, the under-voltage coil Q cannot be maintained and loses power, the armature iron drives the pull rod to enable the half shaft to deflect, the half shaft cannot block the closing mechanism, the closing mechanism can be immediately released, the main loop is disconnected from the power grid, and other faults caused by self-starting are avoided.

Claims (1)

1. The utility model provides a low pressure feed switch comprises three major part in main loop, control circuit and protection circuit, its characterized in that: and two ends of an under-voltage coil in the control loop are connected with a capacitor in parallel, the positive pole of the capacitor is connected with the positive pole of the under-voltage coil circuit, and the negative pole of the capacitor is connected with the negative pole of the under-voltage coil circuit.

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